Shareware Overload Trio 2

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Assembly Source File | 1994-10-12 | 140KB | 3,198 lines

; PMODE v3.04 DPMI/VCPI/XMS/raw protected mode interface kernel. ; Copyright (c) 1994, Tran (a.k.a. Thomas Pytel). public _pm_selectors, _pm_pagetables, _pm_rmstacklen, _pm_rmstacks public _pm_callbacks, _pm_pmstacklen, _pm_pmstacks public _pm_info, _pm_init public pmstackbase, pmstacktop, rmstackbase, rmstacktop .386p locals PMODE_TEXT segment para public use16 'CODE' assume cs:PMODE_TEXT, ds:PMODE_TEXT off equ offset ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; DATA ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ SELCODE = 08h ; PMODE_TEXT code selector SELZERO = 10h ; selector of entire memory space SELCALLBACKDS = 18h ; callback DS selector SELREAL = 20h ; real mode attributes selector SELVCPITSS = 28h ; TSS selector for VCPI SELVCPICODE = 30h ; VCPI call code selector SYSSELECTORS = 9 ; number of system selectors in GDT align 4 dpmiepmode dd ? ; DPMI enter pmode addx codebase dd ? ; PMODE_TEXT linear address vcpistrucaddx dd off vcpi_cr3 ; VCPI switch structure linear address vcpiswitchstack dd ? ; VCPI temporary mode switch stack oldint15vector dd ? ; preserved INT 15h vector pmstacklen dd ? ; protected mode stack length in bytes pmstackbase dd ? ; bottom of protected mode stack area pmstacktop dd ? ; top of protected mode stack area callbackbase dd ? ; base of real mode callbacks callbackseg dw ? ; segment of callbacks selzero dw SELZERO ; for immediate segreg loading selcallbackds dw SELCALLBACKDS ; for immediate segreg loading rawextmemused dw 1 ; raw extended memory used in K rawextmembase dd 0ffffffffh ; raw extended memory base rawextmemtop dd 0 ; raw extended memory top rmstackbase dw ? ; bottom of real mode stack area rmstacktop dw ? ; top of real mode stack area rmstackparmtop dw ? ; for functions 0300h, 0301h, 0302h gdtseg dw ? ; segment of GDT gdtlimit dw ? ; GDT limit | gdtbase dd ? ; GDT base | idtlimit dw 7ffh ; IDT limit | idtbase dd ? ; IDT base | rmidtlimit dw 3ffh ; real mode IDT limit | rmidtbase dd 0 ; real mode IDT base | rmtopmswrout dw off v_rmtopmsw ; addx of real to protected routine pmtormswrout dd off v_pmtormsw ; addx of protected to real routine pagetablebase dd ? ; base of page table area pagetabletop dd ? ; top of page table area pagetablenum db ? ; number of page tables _pm_pagetables db 1 ; number of page tables under VCPI _pm_selectors dw 64 ; max selectors under VCPI/XMS/raw _pm_rmstacklen dw 40h ; real mode stack length, in para _pm_pmstacklen dw 80h ; protected mode stack length, in para _pm_rmstacks db 4 ; real mode stack nesting _pm_pmstacks db 2 ; protected mode stack nesting _pm_callbacks db 16 ; number of real mode callbacks db ? ; for alignment processortype db ? ; processor type | pmodetype db 2 ; protected mode type | picslave db 70h ; PIC slave base interrupt | picmaster db 8 ; PIC master base interrupt | tempd0 label dword ; temporary variables | tempw0 label word ; | tempb0 db ? ; | tempb1 db ? ; | tempw1 label word ; | tempb2 db ? ; | tempb3 db ? ; | tempd1 label dword ; | tempw2 label word ; | tempb4 db ? ; | tempb5 db ? ; | tempw3 label word ; | tempb6 db ? ; | tempb7 db ? ; | xms_callip dw ? ; XMS driver offset | xms_callcs dw ? ; XMS driver segment | vcpi_cr3 dd ? ; VCPI CR3 value for protected mode | vcpi_gdtaddx dd off gdtlimit ; linear addx of GDT limit and base | vcpi_idtaddx dd off idtlimit ; linear addx of IDT limit and base | vcpi_selldt dw 0 ; LDT selector for protected mode | vcpi_seltss dw SELVCPITSS ; TSS selector for protected mode | vcpi_eip dd off v_rmtopmswpm; destination EIP in protected mode | vcpi_cs dw SELCODE ; destination CS in protected mode | vcpi_calleip dd ? ; VCPI protected mode call offset | vcpi_callcs dw SELVCPICODE ; VCPI protected mode call selector | initrouttbl dw r_init, x_init, v_init, d_init int31functbl dw 0900h, 0901h, 0902h, 0000h, 0001h, 0003h, 0006h, 0007h dw 0008h, 0009h, 0200h, 0201h, 0204h, 0205h, 0305h, 0306h dw 0400h dw 000ah, 000bh, 000ch, 000eh, 000fh dw 0300h, 0301h, 0302h dw 0303h, 0304h dw 0500h, 0501h, 0502h, 0503h, 050ah INT31FUNCNUM = ($ - int31functbl) / 2 int31routtbl dw int310900, int310901, int310902, int310000 dw int310001, int310003, int310006, int310007 dw int310008, int310009, int310200, int310201 dw int310204, int310205, int310305, int310306 dw int310400 dw int31000a, int31000b, int31000c, int31000e, int31000f dw int310300, int310301, int310302 dw int310303, int310304 int31mrouttbl dw int310500v, int310501v, int310502v, int310503v dw int31050av int31mxrouttbl dw int310500x, int310501x, int310502x, int310503x dw int31050ax int31mrrouttbl dw int310500r, int310501r, int310502r, int310503r dw int31050ar int31mnrouttbl dw int310500rnomem, int31fail8013, int31fail8023 dw int31fail8023, int31fail8023 ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; DETECT/INIT CODE ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ ; Get protected mode info ; Out: ; AX = return code: ; 0000h = successful ; 0001h = no 80386+ detected ; 0002h = system already in protected mode and no VCPI or DPMI found ; 0003h = DPMI - host is not 32bit ; CF = set on error, if no error: ; BX = number of paragraphs needed for protected mode data (may be 0) ; CL = processor type: ; 03h = 80386 ; 04h = 80486 ; 05h = 80586 ; 06h-FFh = reserved for future use ; CH = protected mode type: ; 00h = raw ; 01h = XMS ; 02h = VCPI ; 03h = DPMI ;░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ _pm_info: push dx si di ds es bx cx ; preserve registers push cs ; DS = CS (PMODE_TEXT) pop ds mov ax,1687h ; check for DPMI int 2fh or ax,ax ; DPMI present? jnz short @@infof0 ; if no, go on mov ax,3 ; error code in case DPMI not 32bit test bl,1 ; is DPMI 32bit? jz @@infofail ; if no, fail mov ax,1 ; error code in case no processor 386+ cmp cl,3 ; is processor 386+? jb @@infofail ; if no, fail mov word ptr dpmiepmode[0],di ; store DPMI initial mode switch addx mov word ptr dpmiepmode[2],es mov bx,si ; BX = number of paragraphs needed mov ch,3 ; pmode type is 3 (DPMI) jmp @@infook ; go to done ok ;----------------------------------------------------------------------------- @@infof0: call detect_processor ; get processor type mov ax,1 ; error code in case no processor 386+ cmp cl,3 ; is processor 386+? jb @@infofail ; if no, fail mov processortype,cl ; store processor type ;----------------------------------------------------------------------------- xor ax,ax ; get INT 67h vector mov es,ax mov ax,es:[67h*4] or ax,es:[67h*4+2] ; is vector NULL jz short @@infof2 ; if yes, no VCPI mov ax,0de00h ; call VCPI installation check int 67h or ah,ah ; AH returned as 0? jnz short @@infof2 ; if no, no VCPI movzx bx,_pm_pagetables ; BX = VCPI page table memory needed shl bx,8 ; 100h paragraphs per page table add bx,100h+0ffh+7+80h ; + page dir + align buf + TSS + IDT mov ch,2 ; pmode type is 2 (VCPI) jmp short @@infof1 ; go to figure other memory needed ;----------------------------------------------------------------------------- @@infof2: smsw ax ; AX = machine status word test al,1 ; is system in protected mode? mov ax,2 ; error code in case protected mode jnz short @@infofail ; if in protected mode, fail mov ax,4300h ; chek for XMS int 2fh cmp al,80h ; XMS present? sete ch ; if yes, pmode type is XMS mov bx,80h ; BX = memory requirement (IDT) ;----------------------------------------------------------------------------- @@infof1: movzx ax,_pm_rmstacks ; size of real mode stack area imul ax,_pm_rmstacklen add bx,ax movzx ax,_pm_pmstacks ; size of protected mode stack area imul ax,_pm_pmstacklen add bx,ax movzx ax,_pm_callbacks ; size of callbacks imul ax,25 add ax,0fh shr ax,4 add bx,ax mov ax,_pm_selectors ; size of GDT add ax,1+SYSSELECTORS+5 shr ax,1 add bx,ax jmp short @@infook ; go to done ok ;----------------------------------------------------------------------------- @@infofail: pop cx bx ; restore BX and CX stc ; carry set, failed jmp short @@infodone ;----------------------------------------------------------------------------- @@infook: mov pmodetype,ch ; store pmode type add sp,4 ; skip BX and CX on stack xor ax,ax ; success code, also clear carry flag ;----------------------------------------------------------------------------- @@infodone: pop es ds di si dx ; restore other registers retf ; return ;───────────────────────────────────────────────────────────────────────────── detect_processor: ; get processor: 386, 486, or 586 xor cl,cl ; processor type 0 in case of exit pushf ; transfer FLAGS to BX pop bx mov ax,bx ; try to clear high 4 bits of FLAGS and ah,0fh push ax ; transfer AX to FLAGS popf pushf ; transfer FLAGS back to AX pop ax and ah,0f0h ; isolate high 4 bits cmp ah,0f0h je short @@detect_processordone ; if bits are set, CPU is 8086/8 mov cl,2 ; processor type 2 in case of exit or bh,0f0h ; try to set high 4 bits of FLAGS push bx ; transfer BX to FLAGS popf pushf ; transfer FLAGS to AX pop ax and ah,0f0h ; isolate high 4 bits jz short @@detect_processordone ; if bits are not set, CPU is 80286 inc cx ; processor type 3 in case of exit push eax ebx ; preserve 32bit registers pushfd ; transfer EFLAGS to EBX pop ebx mov eax,ebx ; try to flip AC bit in EFLAGS xor eax,40000h push eax ; transfer EAX to EFLAGS popfd pushfd ; transfer EFLAGS back to EAX pop eax xor eax,ebx ; AC bit fliped? jz short @@detect_processordone2; if no, CPU is 386 inc cx ; processor type 4 in case of exit mov eax,ebx ; try to flip ID bit in EFLAGS xor eax,200000h push eax ; transfer EAX to EFLAGS popfd pushfd ; transfer EFLAGS back to EAX pop eax xor eax,ebx ; ID bit fliped? jz short @@detect_processordone2; if no, CPU is 486 inc cx ; processor type 5, CPU is 586 @@detect_processordone2: pop ebx eax ; restore 32bit registers @@detect_processordone: ret ; return ;░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ ; Initialize protected mode ; In: ; ES = real mode segment for protected mode data (ignored if not needed) ; Out: ; AX = return code: ; 0000h = successful ; 0001h = no 80386+ detected ; 0002h = system already in protected mode and no VCPI or DPMI found ; 0003h = DPMI - host is not 32bit ; 0004h = could not enable A20 gate ; 0005h = DPMI - could not enter 32bit protected mode ; 0006h = DPMI - could not allocate needed selectors ; CF = set on error, if no error: ; ESP = high word clear ; CS = 16bit selector for real mode CS with limit of 64k ; SS = selector for real mode SS with limit of 64k ; DS = selector for real mode DS with limit of 64k ; ES = selector for PSP with limit of 100h ; FS = 0 (NULL selector) ; GS = 0 (NULL selector) ;░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ _pm_init: push bx cx ; get initial info on protected mode call far ptr _pm_info pop cx bx jnc short @@initf0 ; error? retf ; yup, abort @@initf0: ; no error, init protected mode pushad push ds mov bp,sp push cs ; DS = PMODE_TEXT pop ds cld mov eax,PMODE_TEXT ; set base addx of PMODE_TEXT shl eax,4 mov codebase,eax movzx bx,pmodetype ; jump to appropriate init code shl bx,1 jmp initrouttbl[bx] ;═════════════════════════════════════════════════════════════════════════════ d_init: ; DPMI protected mode init pop ds ; get original caller DS from stack mov ax,1 ; enter DPMI protected mode call cs:dpmiepmode push ds ; put DS back onto stack jnc short dvxr_init ; error? if not, go on with init mov bx,6 ; error entering protected mode, set cmp ax,8011h ; error code and abort stc je short init_done mov bl,5 ; error code 5, not 6 ;----------------------------------------------------------------------------- init_done: ; return with return code mov [bp+30],bx pop ds popad retf ;───────────────────────────────────────────────────────────────────────────── dvxr_init: ; DPMI/VCPI/XMS/raw common init tail mov bx,cs ; BX = CS if needed for same seg exit cmp word ptr [bp+36],PMODE_TEXT ; call came from same segment? je short @@dvxr_initdone ; if yes, done now xor ax,ax ; allocate selector for return code mov cx,1 int 31h jnc short @@dvxr_initf0 mov ah,4ch ; could not allocate selector int 21h ; terminate immediately @@dvxr_initf0: mov bx,ax ; new code descriptor for return mov ax,0007h ; set base address of calling segment xor cx,cx mov dx,[bp+36] shld cx,dx,4 shl dx,4 int 31h mov ax,0008h ; set selector limit of 64k xor cx,cx mov dx,0ffffh int 31h mov ax,0009h ; set selector type and access rights mov dx,cs ; get DPL from current CPL, and access lar cx,dx ; rights and type from current CS shr cx,8 ; type is already 16bit code segment int 31h @@dvxr_initdone: mov [bp+36],bx ; store selector in return address xor bx,bx ; init successful, carry clear jmp init_done ;═════════════════════════════════════════════════════════════════════════════ v_init: ; VCPI protected mode init mov ax,0de0ah ; get PIC mappings int 67h mov picmaster,bl mov picslave,cl mov eax,codebase ; adjust addresses for VCPI structure add vcpi_gdtaddx,eax add vcpi_idtaddx,eax add vcpistrucaddx,eax mov dx,es ; align data area on page add dx,0ffh xor dl,dl mov es,dx movzx eax,dx ; set base and top of page table area shl eax,4 add eax,1000h mov pagetablebase,eax movzx ecx,_pm_pagetables shl ecx,12 add eax,ecx mov pagetabletop,eax xor di,di ; clear page dir and first page table mov cx,1000h xor ax,ax rep stosw mov gs,dx ; FS = segment of page directory lea eax,[edx+100h] mov es,ax ; ES = segment of first page table mov fs,ax ; GS = segment of first page table push ss ; stack space for VCPI descriptors pop ds sub sp,8*3 mov si,sp xor di,di ; get VCPI protected mode interface mov ax,0de01h int 67h push cs ; DS = PMODE_TEXT pop ds mov vcpi_calleip,ebx ; store protected mode VCPI call EIP movzx si,dh ; get physical address of page dir shl si,2 ; from first page table for CR3 lods dword ptr fs:[si] mov vcpi_cr3,eax @@v_initl0: and byte ptr es:[di+1],0f1h ; clear bits 9-11 in copied page table sub di,4 jnc @@v_initl0 mov dx,es ; DX = current page table segment xor ebx,ebx ; index in page dir, also loop counter jmp short @@v_initl1f0 @@v_initl1: xor di,di ; clear page table mov cx,800h xor ax,ax rep stosw @@v_initl1f0: add dx,100h ; increment page table segment mov es,dx lods dword ptr fs:[si] ; set physical address of page table mov gs:[ebx*4],eax ; in page directory inc bx ; increment index in page directory cmp bl,_pm_pagetables ; at end of page tables? jb @@v_initl1 ; if no, loop ;----------------------------------------------------------------------------- push dx ; preserve seg of TSS for later use xor di,di ; clear TSS with all 0, not really mov cx,34h ; needed, but just to be safe xor ax,ax rep stosw mov eax,vcpi_cr3 ; set CR3 in TSS mov es:[1ch],eax mov dword ptr es:[64h],680000h ; set offset of I/O permission bitmap ; and clear T bit add dx,7 ; increment next data area ptr mov es,dx ;───────────────────────────────────────────────────────────────────────────── vxr_init: ; VCPI/XMS/raw common init tail mov ax,es ; set IDT base address movzx ebx,ax shl ebx,4 mov idtbase,ebx movzx bx,_pm_rmstacks ; set top and base of real mode stack imul bx,_pm_rmstacklen ; area for interrupt redirection add ax,80h ; from protected mode mov rmstackbase,ax add ax,bx mov rmstacktop,ax xor di,di ; set up IDT mov dx,word ptr picslave xor ecx,ecx @@vxr_initl0: lea eax,[SELCODE*10000h+ecx*4+off intrmatrix] stosd mov eax,8e00h ; interrupt gate type mov bl,cl ; isolate high 5 bits of int num and bl,0f8h test cl,0f8h ; one of the low 8 interrupts? jz short @@vxr_initl0f0 ; if yes, store as interrupt gate cmp bl,dl ; one of the high IRQs? je short @@vxr_initl0f0 ; if yes, store as interrupt gate cmp bl,dh ; one of the low IRQs? je short @@vxr_initl0f0 ; if yes, store as interrupt gate or ah,1 ; set to trap gate type @@vxr_initl0f0: stosd inc cl ; increment interrupt number jnz @@vxr_initl0 ; loop if more interrupts to go mov word ptr es:[8*31h],off int31 ; protected mode INT 31h mov word ptr es:[8*21h],off int21 ; protected mode INT 21h mov es,rmstacktop ; set next data area ptr to end of ; real mode stack area ;----------------------------------------------------------------------------- mov ax,es ; set protected mode stack area base movzx eax,ax ; for callbacks shl eax,4 mov pmstackbase,eax movzx ecx,_pm_pmstacklen ; set protected mode stack area top movzx ebx,_pm_pmstacks ; for callbacks shl ecx,4 mov pmstacklen,ecx ; protected mode stack size in bytes imul ebx,ecx add ebx,eax mov pmstacktop,ebx ; protected mode stack area top mov cl,_pm_callbacks ; CL = number of callbacks or cl,cl ; any callbacks? jz short @@vxr_initf3 ; if no, done with this part mov callbackbase,ebx ; top of stacks is base of callbacks shr ebx,4 ; BX = seg of callback area mov callbackseg,bx mov es,bx ; ES = seg of callback area xor di,di ; location within callback seg @@vxr_initl1: mov word ptr es:[di],6066h ; PUSHAD instruction mov byte ptr es:[di+2],068h ; PUSH WORD instruction mov word ptr es:[di+3],0 ; immediate 0 used as free flag mov word ptr es:[di+5],06866h ; PUSH DWORD instruction mov byte ptr es:[di+11],0b9h ; MOV CX,? instruction mov word ptr es:[di+14],06866h ; PUSH DWORD instruction mov byte ptr es:[di+20],0eah ; JMP FAR PTR ?:? intruction mov word ptr es:[di+21],off callback mov word ptr es:[di+23],PMODE_TEXT add di,25 ; increment ptr to callback dec cl ; decrement loop counter jnz @@vxr_initl1 ; if more callbacks to do, loop add di,0fh ; align next data area on paragraph shr di,4 add bx,di mov es,bx ; set ES to base of next data area @@vxr_initf3: ;----------------------------------------------------------------------------- mov gdtseg,es ; store segment of GDT mov ax,es ; set GDT base address movzx eax,ax shl eax,4 mov gdtbase,eax mov cx,_pm_selectors ; set GDT limit lea ecx,[8*ecx+8*5+8*SYSSELECTORS-1] mov gdtlimit,cx xor di,di ; clear GDT with all 0 inc cx shr cx,1 xor ax,ax rep stosw cmp pmodetype,2 ; if under VCPI, do VCPI GDT set up jne short @@vxr_initf1 pop ax ; restore TSS seg from stack movzx eax,ax ; set up TSS selector in GDT shl eax,4 mov dword ptr es:[SELVCPITSS+2],eax mov byte ptr es:[SELVCPITSS],67h mov byte ptr es:[SELVCPITSS+5],89h add eax,64h-4*9 ; unused part of TSS is also mov vcpiswitchstack,eax ; temporary switch stack mov di,SELVCPICODE ; copy 3 VCPI descriptors from stack mov si,sp ; to GDT mov cx,4*3 rep movs word ptr es:[di],word ptr ss:[si] add sp,8*3 ; adjust stack @@vxr_initf1: mov word ptr es:[SELZERO],0ffffh; set SELZERO descriptor mov word ptr es:[SELZERO+5],0df92h mov word ptr es:[SELCALLBACKDS],0ffffh ; set callback DS descriptor mov word ptr es:[SELCALLBACKDS+5],0df92h mov word ptr es:[SELREAL],0ffffh; set real mode attributes descriptor mov word ptr es:[SELREAL+5],01092h mov ax,cs ; set SELCODE descriptor (PMODE_TEXT) mov bx,SELCODE ; BX = index to SELCODE descriptor mov cx,0ffffh ; CX = limit (64k) mov dx,109ah ; DX = access rights call vxr_initsetdsc mov bx,8*SYSSELECTORS ; BX = base of free descriptors push bx ; store selector mov ax,ss ; set caller SS descriptor mov dx,5092h call vxr_initsetdsc mov ax,[bp] ; set caller DS descriptor mov [bp],bx ; put DS selector on stack for exit call vxr_initsetdsc push bx ; get PSP segment mov ah,51h int 21h mov si,bx pop bx mov fs,si ; set caller environment descriptor mov ax,fs:[2ch] or ax,ax ; is environment seg 0? jz short @@vxr_initf0 ; if yes, dont convert to descriptor mov fs:[2ch],bx ; store selector value in PSP call vxr_initsetdsc @@vxr_initf0: mov ax,si ; set caller PSP descriptor mov cx,0ffh ; limit is 100h bytes call vxr_initsetdsc ;----------------------------------------------------------------------------- lea ecx,[ebx-8] ; CX = ES descriptor, just set pop dx ; DX = SS descriptor, from stack mov ax,SELZERO ; AX = DS descriptor, SELZERO movzx ebx,sp ; EBX = SP, current SP - same stack mov si,SELCODE ; target CS is SELCODE, same segment mov edi,off @@vxr_initf2 ; target EIP jmp rmtopmswrout ; jump to mode switch routine @@vxr_initf2: mov edi,cs:codebase ; EDI = offset of PMODE_TEXT from 0 mov eax,ds:[4*15h] ; get INT 15h vector mov ds:oldint15vector[edi],eax ; store INT 15h vector mov esi,cs:rawextmembase ; ESI = raw base of extended memory cmp esi,cs:rawextmemtop ; is there any raw extended memory? jae dvxr_init ; if no, go DPMI/VCPI/XMS/raw init dw 0b866h,off int15,PMODE_TEXT ; MOV EAX,PMODE_TEXT:offset int15 mov ds:[4*15h],eax ; set new INT 15h handler mov edi,cs:rawextmemtop ; EDI = raw top of extended memory mov eax,edi ; EAX = size of extended memory sub eax,esi sub eax,10h ; subtract memory control block size mov [edi-16],eax ; store size in memory control block xor eax,eax mov [edi-12],eax ; no next memory control block mov [edi-8],eax ; no previous memory control block mov [edi-4],al ; memory block is free jmp dvxr_init ; go to DPMI/VCPI/XMS/raw init tail ;───────────────────────────────────────────────────────────────────────────── vxr_initsetdsc: ; set descriptor for VCPI/XMS/raw init movzx eax,ax ; EAX = base of segment shl eax,4 mov word ptr es:[bx],cx ; limit = CX mov dword ptr es:[bx+2],eax ; base address = EAX mov word ptr es:[bx+5],dx ; access rights = DX add bx,8 ; increment descriptor index ret ;═════════════════════════════════════════════════════════════════════════════ x_init: ; XMS protected mode init push es ; preserve ES, INT 2Fh destroys it mov ax,4310h ; get XMS driver address int 2fh mov xms_callip,bx ; store XMS driver address mov xms_callcs,es pop es ; restore ES (buffer segment) mov ah,3 ; enable A20 call dword ptr xms_callip mov bx,4 ; error code 0004h in case of error cmp ax,1 ; error enabling A20? jc init_done ; if yes, exit with error 0004h mov si,off int31mxrouttbl ; set XMS memory allocation functions ;───────────────────────────────────────────────────────────────────────────── xr_init: ; XMS/raw common init tail push es ; preserve ES, INT 2Fh destroys it push ds ; ES = DS for table copy pop es mov di,off int31mrouttbl ; copy memory allocation function mov cx,5 ; addresses to table rep movsw pop es ; restore ES (buffer segment) mov rmtopmswrout,off xr_rmtopmsw; set XMS/raw mode switch addresses mov pmtormswrout,off xr_pmtormsw jmp vxr_init ; go to VCPI/XMS/raw continue init ;═════════════════════════════════════════════════════════════════════════════ r_init: ; raw protected mode init mov ah,88h ; how much extended memory free int 15h mov si,off int31mnrouttbl ; SI -> no memory allocation functions or ax,ax ; if none, done with raw init jz xr_init movzx eax,ax ; convert AX K to ptr to top of mem shl eax,10 add eax,100000h mov cs:rawextmemtop,eax call enablea20 ; enable A20 push es ; preserve ES (buffer segment) xor cx,cx ; ES -> 0 (interrupt vector table) mov es,cx les bx,dword ptr es:[4*19h] ; ES:BX -> int vector table mov eax,100000h ; initial free extended memory base cmp dword ptr es:[bx+12h],'SIDV'; VDISK memory allocation? jne short @@r_initf0 ; if present, get base of free mem mov eax,dword ptr es:[bx+2ch] ; get first free byte of extended mem add eax,0fh ; align on paragraph and eax,0fffff0h ; address is only 24bit @@r_initf0: dec cx ; ES -> 0ffffh for ext mem addressing mov es,cx cmp dword ptr es:[13h],'SIDV' ; VDISK memory allocation? jne short @@r_initf1 ; if present, get base of free mem movzx ebx,word ptr es:[2eh] ; get first free K of extended memory shl ebx,10 ; adjust K to bytes cmp eax,ebx ; pick larger of 2 addresses ja short @@r_initf1 mov eax,ebx @@r_initf1: pop es ; restore ES (buffer segment) mov si,off int31mnrouttbl ; SI -> no memory allocation functions cmp eax,cs:rawextmemtop ; any valid free extended memory jae xr_init ; if none, done with raw init mov cs:rawextmembase,eax mov si,off int31mrrouttbl ; set raw memory allocation functions jmp xr_init ; go to XMS/raw continue init ;───────────────────────────────────────────────────────────────────────────── enablea20: ; hardware enable gate A20 pushf push fs gs cli xor ax,ax ; set A20 test segments 0 and 0ffffh mov fs,ax dec ax mov gs,ax call enablea20test ; is A20 already enabled? jz short @@enablea20done ; if yes, done in al,92h ; PS/2 A20 enable or al,2 jmp short $+2 jmp short $+2 jmp short $+2 out 92h,al call enablea20test ; is A20 enabled? jz short @@enablea20done ; if yes, done call enablea20kbwait ; AT A20 enable jnz short @@enablea20f0 mov al,0d1h out 64h,al call enablea20kbwait jnz short @@enablea20f0 mov al,0dfh out 60h,al call enablea20kbwait @@enablea20f0: ; wait for A20 to enable mov cx,800h ; do 800h tries @@enablea20l0: call enablea20test ; is A20 enabled? jz @@enablea20done ; if yes, done in al,40h ; get current tick counter jmp short $+2 jmp short $+2 jmp short $+2 in al,40h mov ah,al @@enablea20l1: ; wait a single tick in al,40h jmp short $+2 jmp short $+2 jmp short $+2 in al,40h cmp al,ah je @@enablea20l1 loop @@enablea20l0 ; loop for another try mov bp,sp ; error, A20 did not enable mov ax,4 ; error code 4 mov word ptr [bp+6],off init_done ; set init_done return address @@enablea20done: pop gs fs popf ret ;----------------------------------------------------------------------------- enablea20kbwait: ; wait for safe to write to 8042 xor cx,cx @@enablea20kbwaitl0: jmp short $+2 jmp short $+2 jmp short $+2 in al,64h ; read 8042 status test al,2 ; buffer full? loopnz @@enablea20kbwaitl0 ; if yes, loop ret ;----------------------------------------------------------------------------- enablea20test: ; test for enabled A20 mov al,fs:[0] ; get byte from 0:0 mov ah,al ; preserve old byte not al ; modify byte xchg al,gs:[10h] ; put modified byte to 0ffffh:10h cmp ah,fs:[0] ; set zero if byte at 0:0 not modified mov gs:[10h],al ; put back old byte at 0ffffh:10h ret ; return, zero if A20 enabled ;═════════════════════════════════════════════════════════════════════════════ int15: ; real mode INT 15h handler cmp ah,88h ; function 88h? je short @@int15f0 ; if yes, need to process jmp cs:oldint15vector ; no, go on to old INT 15h handler @@int15f0: pushf ; call old int 15h handler call cs:oldint15vector sub ax,cs:rawextmemused ; adjust AX by extended memory used push bp ; clear carry flag on stack for IRET mov bp,sp and byte ptr [bp+6],0feh pop bp iret ; return with new AX extended memory ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; PROTECTED MODE KERNEL CODE ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;═════════════════════════════════════════════════════════════════════════════ v_rmtopmsw: ; VCPI real to protected switch pushf ; store FLAGS cli push cs ; DS = PMODE_TEXT pop ds pop tempw0 ; move FLAGS from stack to temp mov tempw1,ax ; store AX (protected mode DS) mov tempw2,si ; store SI (protected mode CS) mov esi,vcpistrucaddx ; ESI = linear addx of VCPI structure mov ax,0de0ch ; VCPI switch to protected mode int 67h v_rmtopmswpm: mov ss,dx ; load protected mode SS:ESP mov esp,ebx mov ds,cs:tempw1 ; load protected mode DS mov es,cx ; load protected mode ES xor ax,ax mov fs,ax ; load protected mode FS with NULL mov gs,ax ; load protected mode GS with NULL pushfd ; store EFLAGS mov ax,cs:tempw0 ; move bits 0-11 of old FLAGS onto and ah,0fh ; stack for IRETD mov [esp],ax push cs:tempd1 ; store protected mode target CS push edi ; store protected mode target EIP iretd ; go to targed addx in protected mode ;═════════════════════════════════════════════════════════════════════════════ v_pmtormsw: ; VCPI protected to real switch pushf ; store FLAGS cli push ax ; store AX (real mode DS) mov ds,cs:selzero ; DS -> 0 (beginning of memory) movzx ebx,bx ; clear high word of EBX, real mode SP movzx edx,dx ; clear high word of EDX, real mode SS mov eax,cs:vcpiswitchstack ; EAX -> top of temporary switch stack mov dword ptr ds:[eax+32],0 ; store real mode GS mov dword ptr ds:[eax+28],0 ; store real mode FS movzx ecx,cx ; clear high word of ECX, real mode ES mov ds:[eax+20],ecx ; store real mode ES pop cx ; move real mode DS from protected mov ds:[eax+24],ecx ; mode stack to VCPI call stack mov ds:[eax+16],edx ; store real mode SS mov ds:[eax+12],ebx ; store real mode SP mov dword ptr ds:[eax+4],PMODE_TEXT ; store real mode CS mov dword ptr ds:[eax+0],off @@v_pmtormswf0 ; store real mode IP pop bx ; restore FLAGS from stack mov ss,cs:selzero ; SS -> 0 (beginning of memory) mov esp,eax ; ESP = stack ptr for VCPI call mov ax,0de0ch ; VCPI switch to real mode (V86) call fword ptr cs:vcpi_calleip @@v_pmtormswf0: push bx ; store old FLAGS push si ; store target CS in real mode push di ; store target IP in real mode iret ; go to target addx in real mode ;═════════════════════════════════════════════════════════════════════════════ xr_rmtopmsw: ; XMS/raw real to protected switch pushfd ; store EFLAGS cli push ax ; store AX (protected mode DS) lidt fword ptr cs:idtlimit ; load protected mode IDT lgdt fword ptr cs:gdtlimit ; load protected mode GDT mov eax,cr0 ; switch to protected mode or al,1 mov cr0,eax db 0eah ; JMP FAR PTR SELCODE:$+4 dw $+4,SELCODE ; (clear prefetch que) pop ds ; load protected mode DS mov es,cx ; load protected mode ES xor ax,ax mov fs,ax ; load protected mode FS with NULL mov gs,ax ; load protected mode GS with NULL pop eax mov ss,dx ; load protected mode SS:ESP mov esp,ebx and ah,0bfh ; set NT=0 in old EFLAGS push ax ; set current FLAGS popf push eax ; store old EFLAGS push esi ; store protected mode target CS push edi ; store protected mode target EIP iretd ; go to targed addx in protected mode ;═════════════════════════════════════════════════════════════════════════════ xr_pmtormsw: ; XMS/raw protected to real switch push cx ; store CX (real mode ES) pushf ; store FLAGS cli push ax ; store AX (real mode DS) mov ds,cs:selzero ; DS -> 0 (beginning of memory) mov ecx,cs:codebase ; get offset of PMODE_TEXT from 0 pop ds:tempw0[ecx] ; move real mode DS from stack to temp pop ds:tempw1[ecx] ; move FLAGS from stack to temp pop cx ; restore CX (real mode ES) mov ax,SELREAL ; load descriptors with real mode seg mov ds,ax ; attributes mov es,ax mov fs,ax mov gs,ax mov ss,ax ; load descriptor with real mode attr movzx esp,bx ; load real mode SP, high word 0 lidt fword ptr cs:rmidtlimit ; load real mode IDT mov eax,cr0 ; switch to real mode and al,0feh mov cr0,eax db 0eah ; JMP FAR PTR PMODE_TEXT:$+4 dw $+4,PMODE_TEXT ; (clear prefetch que) mov ss,dx ; load real mode SS mov ds,cs:tempw0 ; load real mode DS mov es,cx ; load real mode ES xor ax,ax mov fs,ax ; load real mode FS with NULL mov gs,ax ; load real mode GS with NULL push cs:tempw1 ; store old FLAGS push si ; store real mode target CS push di ; store real mode target IP iret ; go to target addx in real mode ;═════════════════════════════════════════════════════════════════════════════ vxr_saverestorerm: ; VCPI/XMS/raw save/restore status retf ; no save/restore needed, 16bit RETF ;═════════════════════════════════════════════════════════════════════════════ vxr_saverestorepm: ; VCPI/XMS/raw save/restore status db 66h,0cbh ; no save/restore needed, 32bit RETF ;═════════════════════════════════════════════════════════════════════════════ critical_error: ; some unrecoverable error cli ; make sure we are not interrupted in al,61h ; beep or al,3 out 61h,al jmp $ ; now hang ;═════════════════════════════════════════════════════════════════════════════ callback: ; real mode callback handler mov ax,sp ; preserve SS:SP for callback push ss push ax push gs fs ds es ; preserve real mode regs for callback pushf ; preserve FLAGS for callback cli cld mov ebp,cs:pmstacktop ; EBP = ESP for protected mode mov ebx,ebp ; set EBX to next stack location sub ebx,cs:pmstacklen mov cs:pmstacktop,ebx ; update ptr for possible reenterancy cmp ebx,cs:pmstackbase ; exceeded protected mode stack space? jb critical_error ; if yes, critical error (hang) xor eax,eax ; EAX = base address of SS mov ax,ss shl eax,4 movzx ebx,sp ; EBX = current linear SS:SP add ebx,eax mov es,cs:gdtseg ; set for protected mode callback DS or eax,92000000h ; base address in GDT mov es:[SELCALLBACKDS+2],eax mov ax,SELZERO ; DS selector for protected mode mov dx,ax ; SS selector = DS selector mov si,SELCODE ; target protected mode CS:EIP mov edi,offset @@callbackf0 jmp cs:rmtopmswrout ; go to protected mode @@callbackf0: mov edi,[esp+14] ; EDI -> register structure from stack lea esi,[esp+24] ; copy general registers from stack mov ecx,8 ; to register structure rep movs dword ptr es:[edi],dword ptr ds:[esi] mov esi,esp ; copy FLAGS, ES, DS, FG, and GS movs word ptr es:[edi],word ptr ds:[esi] movs dword ptr es:[edi],dword ptr ds:[esi] movs dword ptr es:[edi],dword ptr ds:[esi] lods dword ptr ds:[esi] ; EAX = real mode SS:SP from stack add ax,42 ; adjust SP for stuff on stack mov es:[edi+4],eax ; put in register structure mov ds,cs:selcallbackds ; DS = callback DS selector sub edi,42 ; EDI -> register structure movzx esi,ax ; ESI = old real mode SP xchg esp,ebp ; ESP = protected mode stack pushfd ; push flags for IRETD from callback db 66h ; push 32bit CS for IRETD push cs dw 6866h,@@callbackf1,0 ; push 32bit EIP for IRETD movzx eax,word ptr [ebp+22] ; EAX = target CS of callback push eax ; push 32bit CS for RETF to callback push dword ptr [ebp+18] ; push 32bit EIP for retf db 66h ; 32bit RETF to callback retf @@callbackf1: cli cld push es ; DS:ESI = register structure pop ds mov esi,edi mov es,cs:selzero ; ES -> 0 (beginning of memory) movzx ebx,word ptr [esi+2eh] ; EBX = real mode SP from structure movzx edx,word ptr [esi+30h] ; EDX = real mode SS from structure sub bx,42 ; subtract size of vars to be put mov ebp,[esi+0ch] ; EBP = pushed ESP from real mode mov bp,bx ; EBP = old high & new low word of ESP lea edi,[edx*4] ; EDI -> real mode base of stack lea edi,[edi*4+ebx] ; of vars to be stored mov ecx,8 ; copy general registers to stack rep movs dword ptr es:[edi],dword ptr ds:[esi] mov eax,[esi+6] ; EAX = return FS and GS for real mode mov es:[edi],eax ; store on real mode stack for return mov ax,[esi] ; AX = return FLAGS for real mode mov es:[edi+8],ax ; store on real mode stack for return mov eax,[esi+10] ; EAX = return CS:IP for real mode mov es:[edi+4],eax ; store on real mode stack for return mov ax,[esi+4] ; AX = return DS for real mode mov cx,[esi+2] ; CX = return ES for real mode mov si,PMODE_TEXT ; real mode target CS:IP mov di,off @@callbackf2 db 66h ; JMP DWORD PTR, as in 32bit offset, jmp word ptr cs:pmtormswrout ; not seg:16bit offset @@callbackf2: mov esp,ebp ; restore total ESP, old high word mov eax,cs:pmstacklen ; restore top of protected mode stack add cs:pmstacktop,eax popad ; get callback return general regs pop fs gs ; get callback return FS and GS values iret ; go to callback return CS:IP ;═════════════════════════════════════════════════════════════════════════════ intrmatrix: ; INT redirectors for all INTs rept 100h call near ptr intr ; 3 byte CALL nop ; 1 byte NOP to align on 4 endm ;═════════════════════════════════════════════════════════════════════════════ intr: ; general interrupt redirector cli sub esp,2 xchg eax,[esp] ; store EAX, also get CALL address push ecx edx ebx esp ebp esi edi; store rest of registers for POPAD push ds es fs gs mov ds,cs:selzero ; DS -> 0 (beginning of memory) mov edi,cs:codebase ; EDI = offset of PMODE_TEXT from 0 mov dx,cs:rmstacktop ; DX = SS for real mode redirection movzx ebp,dx ; EBP -> top of real mode stack shl ebp,4 mov bx,cs:_pm_rmstacklen ; get size of real mode stack sub dx,bx ; adjust DX to next stack location mov ds:rmstacktop[edi],dx ; update ptr for possible reenterancy shl bx,4 ; set real mode SP to top of stack cmp dx,cs:rmstackbase ; exceeded real mode stack space? jb critical_error ; if yes, critical error (hang) mov ds:[ebp-2],ss ; store SS:ESP on real mode stack mov ds:[ebp-6],esp shr eax,16 ; move CALL address to AX sub ax,off intrmatrix ; AX = int number, since AX is: shr ax,2 ; intrmatrix + (int number * 4) mov ah,al ; AH = high 5 bits of int number and ah,0f8h cmp ah,cs:picslave ; high IRQ? je short intrirq ; if yes, do IRQ cmp ah,cs:picmaster ; low IRQ? jne short intrint ; if no, do INT (with general regs) ;----------------------------------------------------------------------------- intrirq: ; an IRQ redirection mov ds:@@intrirqintnum[edi],al ; modify code with interrupt number mov si,PMODE_TEXT ; real mode target CS:IP mov di,off @@intrirqf0 sub bx,6 ; adjust real mode SP for stored vars db 66h ; JMP DWORD PTR, as in 32bit offset, jmp word ptr cs:pmtormswrout ; not seg:16bit offset @@intrirqf0: db 0cdh ; INT @@intrirqintnum @@intrirqintnum db ? mov ax,SELZERO ; DS selector value for protected mode mov cx,ax ; ES selector value for protected mode pop ebx ; get protected mode SS:ESP from stack pop dx mov si,SELCODE ; target CS:EIP in protected mode mov edi,off @@intrirqf1 jmp cs:rmtopmswrout ; go back to protected mode @@intrirqf1: mov edi,cs:codebase ; restore top of real mode stack mov ax,cs:_pm_rmstacklen add ds:rmstacktop[edi],ax pop gs fs es ds ; restore all registers popad iretd ;----------------------------------------------------------------------------- intrint: ; an INT redirection mov ds:@@intrintintnum[edi],al ; modify code with interrupt number mov es,cs:selzero ; copy registers from protected mode lea edi,[ebp-26h] ; stack to real mode stack lea esi,[esp+8] mov ecx,8 cld rep movs dword ptr es:[edi],dword ptr ss:[esi] mov si,PMODE_TEXT ; real mode target CS:IP mov di,off @@intrintf0 sub bx,26h ; adjust real mode SP for stored vars db 66h ; JMP DWORD PTR, as in 32bit offset, jmp word ptr cs:pmtormswrout ; not seg:16bit offset @@intrintf0: popad ; load regs with int call values db 0cdh ; INT @@intrirqintnum @@intrintintnum db ? pushad ; store registers on stack pushf ; store flags on stack cli xor eax,eax ; EAX = linear ptr to SS mov ax,ss shl eax,4 movzx ebp,sp ; EBP = SP mov ebx,[bp+22h] ; get protected mode SS:ESP from stack mov dx,[bp+26h] add ebp,eax ; EBP -> stored regs on stack mov ax,SELZERO ; DS selector value for protected mode mov cx,ax ; ES selector value for protected mode mov si,SELCODE ; target CS:EIP in protected mode mov edi,off @@intrintf1 jmp cs:rmtopmswrout ; go back to protected mode @@intrintf1: mov edi,cs:codebase ; restore top of real mode stack mov ax,cs:_pm_rmstacklen add ds:rmstacktop[edi],ax mov ax,ds:[ebp] ; move return FLAGS from real mode and ax,8d5h ; stack to protected mode stack mov bx,[esp+30h] and bx,not 8d5h or ax,bx mov [esp+30h],ax mov edi,ds:[ebp+2] ; restore return registers from real mov esi,ds:[ebp+6] ; mode stack mov ebx,ds:[ebp+18] mov edx,ds:[ebp+22] mov ecx,ds:[ebp+26] mov eax,ds:[ebp+30] mov ebp,ds:[ebp+10] pop gs fs es ds ; restore segment regs add esp,20h ; skip old general registers on stack iretd ;═════════════════════════════════════════════════════════════════════════════ int21: ; watch for INT 21h AH=4Ch cmp ah,4ch ; AH = 4Ch? jne intrmatrix+4*21h ; if no, go to INT 21h redirection mov ds,cs:selzero ; DS -> 0 (beginning of memory) mov edi,cs:codebase ; EDI = offset of PMODE_TEXT from 0 mov ebx,cs:oldint15vector ; put back old INT 15h handler mov ds:[4*15h],ebx jmp intrmatrix+4*21h ; go to INT 21h redirection ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; INT 31h INTERFACE ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;═════════════════════════════════════════════════════════════════════════════ int31: ; protected mode INT 31h handler cli cld push ds es fs gs ; push regs needed pushad mov ds,cs:selzero ; DS -> 0 (beginning of memory) push bx mov bx,(INT31FUNCNUM - 1) * 2 ; number of functions to check @@int31l0: cmp ax,cs:int31functbl[bx] ; found function value? jne short @@int31l0c mov bx,cs:int31routtbl[bx] ; yes, go to appropriate handler xchg bx,[esp] ret @@int31l0c: sub bx,2 ; no, continue loop jnc @@int31l0 pop bx ; no function found jmp int31fail8001 ; error 8001h ;----------------------------------------------------------------------------- int31fail8024: ; INT 31h return fail with error 8024h mov word ptr [esp+28],8024h ; set AX on stack to 8024h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8023: ; INT 31h return fail with error 8023h mov word ptr [esp+28],8023h ; set AX on stack to 8023h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8022: ; INT 31h return fail with error 8022h mov word ptr [esp+28],8022h ; set AX on stack to 8022h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8021: ; INT 31h return fail with error 8021h mov word ptr [esp+28],8021h ; set AX on stack to 8021h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8016: ; INT 31h return fail with error 8016h mov word ptr [esp+28],8016h ; set AX on stack to 8016h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8015: ; INT 31h return fail with error 8015h mov word ptr [esp+28],8015h ; set AX on stack to 8015h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8013: ; INT 31h return fail with error 8013h mov word ptr [esp+28],8013h ; set AX on stack to 8013h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8012: ; INT 31h return fail with error 8012h mov word ptr [esp+28],8012h ; set AX on stack to 8012h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8011: ; INT 31h return fail with error 8011h mov word ptr [esp+28],8011h ; set AX on stack to 8011h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8010: ; INT 31h return fail with error 8010h mov word ptr [esp+28],8010h ; set AX on stack to 8010h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31fail8001: ; INT 31h return fail with error 8001h mov word ptr [esp+28],8001h ; set AX on stack to 8001h for POPAD jmp short int31fail ;----------------------------------------------------------------------------- int31failcx: ; INT 31h return fail with CX,AX mov word ptr [esp+24],cx ; put CX onto stack for POPAD ;----------------------------------------------------------------------------- int31failax: ; INT 31h return fail with AX mov word ptr [esp+28],ax ; put AX onto stack for POPAD ;----------------------------------------------------------------------------- int31fail: ; INT 31h return fail, pop all regs popad pop gs fs es ds ;----------------------------------------------------------------------------- int31failnopop: ; INT 31h return fail with carry set or byte ptr [esp+8],1 ; set carry in EFLAGS on stack iretd ;----------------------------------------------------------------------------- int31okdx: ; INT 31h return ok with DX,CX,AX mov [esp+20],dx ; put CX onto stack for POPAD jmp short int31okcx ;----------------------------------------------------------------------------- int31oksinoax: ; INT 31h return ok SI,DI,BX,CX mov ax,[esp+28] ; get old value of AX for restore ;----------------------------------------------------------------------------- int31oksi: ; INT 31h return ok SI,DI,BX,CX,AX mov [esp+4],si ; put SI onto stack for POPAD mov [esp],di ; put DI onto stack for POPAD mov [esp+16],bx ; put BX onto stack for POPAD ;----------------------------------------------------------------------------- int31okcx: ; INT 31h return ok with CX,AX mov [esp+24],cx ; put CX onto stack for POPAD ;----------------------------------------------------------------------------- int31okax: ; INT 31h return ok with AX mov [esp+28],ax ; put AX onto stack for POPAD ;----------------------------------------------------------------------------- int31ok: ; INT 31h return ok, pop all regs popad pop gs fs es ds ;----------------------------------------------------------------------------- int31oknopop: ; INT 31h return ok with carry clear and byte ptr [esp+8],0feh ; clear carry in EFLAGS on stack iretd ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; DESCRIPTOR FUNCTIONS ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;----------------------------------------------------------------------------- int31testsel: ; test for valid selector BX pop bp ; pop return address cmp bx,cs:gdtlimit ; selector BX out of range? ja int31fail8022 ; if yes, fail with error 8022h mov edi,cs:gdtbase ; get base of GDT and bl,0f8h ; mask offset table index and RPL movzx ebx,bx ; EBX = selector index test byte ptr ds:[edi+ebx+6],10h; is descriptor used? jz int31fail8022 ; if descriptor not used, fail 8022h jmp bp ; return ok ;----------------------------------------------------------------------------- int31testaccess: ; test access bits in CX pop bp ; pop return address test ch,20h ; test MUST BE 0 bit in CH jnz int31fail8021 ; if not 0, error 8021h test cl,90h ; test present and MUST BE 1 bits jz int31fail8021 ; if both 0, error 8021h jpo int31fail8021 ; if unequal, error 8021h test cl,60h ; test DPL jnz int31fail8021 ; if not 0, error 8021h test cl,8 ; if code, more tests needed jz short @@int31testselok ; if data, skip code tests test cl,6 ; test conforming and readable bits jz int31fail8021 ; if both 0, error 8021h jpe int31fail8021 ; if equal, error 8021h @@int31testselok: jmp bp ; return ok ;───────────────────────────────────────────────────────────────────────────── int310000: ; allocate descriptors or cx,cx ; if CX = 0, error 8021h jz int31fail8021 mov edx,cs:gdtbase ; get base of GDT movzx eax,cs:gdtlimit ; EAX = last selector index and al,0f8h mov bx,cx ; BX = number of selectors to find @@int310000l0: test byte ptr ds:[edx+eax+6],10h; is descriptor used? jnz short @@int310000l0f0 dec bx ; found free descriptor, dec counter jnz short @@int310000l0f1 ; continue if need to find more mov ebx,eax ; found all descriptors requested @@int310000l1: mov dword ptr ds:[edx+ebx],0 ; set entire new descriptor mov dword ptr ds:[edx+ebx+4],109200h add bx,8 ; increment selector index dec cx ; dec counter of descriptors to mark jnz @@int310000l1 ; loop if more to mark jmp int31okax ; return ok, with AX @@int310000l0f0: mov bx,cx ; reset number of selectors to find @@int310000l0f1: sub ax,8 ; dec current selector counter cmp ax,8*SYSSELECTORS ; more descriptors to go? jae @@int310000l0 ; if yes, loop jmp int31fail8011 ; did not find descriptors ;───────────────────────────────────────────────────────────────────────────── int310001: ; free descriptor call int31testsel ; test for valid selector BX and byte ptr ds:[edi+ebx+6],0efh; mark descriptor as free mov cx,4 ; zero any segregs loaded with BX lea ebp,[esp+32] ; EBP -> selectors on stack @@int310001l0: cmp word ptr [ebp],bx ; selector = BX? jne short @@int310001l0f0 ; if no, continue loop mov word ptr [ebp],0 ; zero selector on stack @@int310001l0f0: add ebp,2 ; increment selector ptr loop @@int310001l0 ; loop jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310003: ; get selector increment value mov ax,8 ; selector increment value is 8 jmp int31okax ; return ok, with AX ;───────────────────────────────────────────────────────────────────────────── int310006: ; get segment base address call int31testsel ; test for valid selector BX mov dx,word ptr ds:[edi+ebx+2] ; low word of 32bit linear address mov cl,byte ptr ds:[edi+ebx+4] ; high word of 32bit linear address mov ch,byte ptr ds:[edi+ebx+7] jmp int31okdx ; return ok, with DX, CX, AX ;───────────────────────────────────────────────────────────────────────────── int310007: ; set segment base address call int31testsel ; test for valid selector BX mov word ptr ds:[edi+ebx+2],dx ; low word of 32bit linear address mov byte ptr ds:[edi+ebx+4],cl ; high word of 32bit linear address mov byte ptr ds:[edi+ebx+7],ch jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310008: ; set segment limit call int31testsel ; test for valid selector BX cmp cx,0fh ; limit greater than 1M? jbe short @@int310008f0 mov ax,dx ; yup, limit greater than 1M and ax,0fffh cmp ax,0fffh ; low 12 bits set? jne int31fail8021 ; if no, error 8021h shrd dx,cx,12 ; DX = low 16 bits of page limit shr cx,12 ; CL = high 4 bits of page limit or cl,80h ; set granularity bit in CL @@int310008f0: mov word ptr ds:[edi+ebx],dx ; put low word of limit and byte ptr ds:[edi+ebx+6],70h ; mask off G and high nybble of limit or byte ptr ds:[edi+ebx+6],cl ; put high nybble of limit jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310009: ; set descriptor access rights call int31testsel ; test for valid selector BX call int31testaccess ; test access bits in CX or ch,10h ; set AVL bit, descriptor used and ch,0f0h ; mask off low nybble of CH and byte ptr ds:[edi+ebx+6],0fh ; mask off high nybble access rights or byte ptr ds:[edi+ebx+6],ch ; or in high access rights byte mov byte ptr ds:[edi+ebx+5],cl ; put low access rights byte jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int31000a: ; create alias descriptor call int31testsel ; test for valid selector BX mov ax,0000h ; allocate descriptor mov cx,1 int 31h jc int31fail8011 ; if failed, descriptor unavailable push ax ; preserve allocated selector push ds ; copy descriptor and set type data pop es movzx edi,ax ; EDI = target selector mov esi,cs:gdtbase ; ESI -> GDT add edi,esi ; adjust to target descriptor in GDT add esi,ebx ; adjust to source descriptor in GDT movs dword ptr es:[edi],dword ptr ds:[esi] ; copy descriptor lods dword ptr ds:[esi] mov ah,92h ; set descriptor type - R/W up data stos dword ptr es:[edi] pop ax ; restore allocated selector jmp int31okax ; return ok, with AX ;───────────────────────────────────────────────────────────────────────────── int31000b: ; get descriptor call int31testsel ; test for valid selector BX lea esi,[edi+ebx] ; ESI -> descriptor in GDT mov edi,[esp] ; get EDI buffer ptr from stack movs dword ptr es:[edi],dword ptr ds:[esi] ; copy descriptor movs dword ptr es:[edi],dword ptr ds:[esi] jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int31000c: ; set descriptor call int31testsel ; test for valid selector BX mov esi,[esp] ; ESI = EDI buffer ptr from stack mov cx,es:[esi+5] ; get access rights from descriptor call int31testaccess ; test access bits in CX push ds ; swap DS and ES, target and source push es pop ds pop es add edi,ebx ; adjust EDI to descriptor in GDT movs dword ptr es:[edi],dword ptr ds:[esi] ; copy descriptor lods dword ptr ds:[esi] or eax,100000h ; set descriptor AVL bit stos dword ptr es:[edi] jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int31000e: ; get multiple descriptors mov ax,000bh ; function 000bh, get descriptor ;----------------------------------------------------------------------------- int31000ef: ; common to funcions 000eh and 000fh or cx,cx ; if CX = 0, return ok immediately jz int31ok mov dx,cx ; DX = number of descriptors xor cx,cx ; CX = successful counter @@int31000efl0: mov bx,es:[edi] ; BX = selector to get add edi,2 int 31h ; get/set descriptor jc int31failcx ; if error, fail with AX and CX add edi,8 ; increment descriptor ptr inc cx ; increment successful copy counter dec dx ; decrement loop counter jnz @@int31000efl0 ; if more descriptors to go, loop jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int31000f: ; set multiple descriptors mov ax,000ch ; function 000ch, set descriptor jmp int31000ef ; go to common function ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; INTERRUPT FUNCTIONS ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;───────────────────────────────────────────────────────────────────────────── int310200: ; get real mode interrupt vector movzx ebx,bl ; EBX = BL (interrupt number) mov dx,ds:[ebx*4] ; load real mode vector offset mov cx,ds:[ebx*4+2] ; load real mode vector segment jmp int31okdx ; return ok, with AX, CX, DX ;───────────────────────────────────────────────────────────────────────────── int310201: ; set real mode interrupt vector movzx ebx,bl ; EBX = BL (interrupt number) mov ds:[ebx*4],dx ; set real mode vector offset mov ds:[ebx*4+2],cx ; set real mode vector segment jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310204: ; get protected mode interrupt vector movzx ebx,bl ; EBX = BL (interrupt number) shl ebx,3 ; adjust for location in IDT add ebx,cs:idtbase ; add base of IDT mov edx,dword ptr ds:[ebx+4] ; get high word of offset mov dx,word ptr ds:[ebx] ; get low word of offset mov cx,word ptr ds:[ebx+2] ; get selector jmp int31okdx ; return ok, with AX, CX, DX ;───────────────────────────────────────────────────────────────────────────── int310205: ; set protected mode interrupt vector xchg bx,cx ; swap int number with int selector call int31testsel ; test for valid selector BX movzx ecx,cl ; ECX = CL (interrupt number) shl ecx,3 ; adjust for location in IDT add ecx,cs:idtbase ; add base of IDT mov word ptr ds:[ecx],dx ; set low word of offset shr edx,16 mov word ptr ds:[ecx+6],dx ; set high word of offset mov word ptr ds:[ecx+2],bx ; set selector jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310900: ; get and disable interrupt state add esp,26h ; adjust stack pop ds ; restore DS btc word ptr [esp+8],9 ; test and clear IF bit in EFLAGS setc al ; set AL = carry (IF flag from EFLAGS) jmp int31oknopop ; return ok, dont pop registers ;───────────────────────────────────────────────────────────────────────────── int310901: ; get and enable interrupt state add esp,26h ; adjust stack pop ds ; restore DS bts word ptr [esp+8],9 ; test and set IF bit in EFLAGS setc al ; set AL = carry (IF flag from EFLAGS) jmp int31oknopop ; return ok, dont pop registers ;───────────────────────────────────────────────────────────────────────────── int310902: ; get interrupt state add esp,26h ; adjust stack pop ds ; restore DS bt word ptr [esp+8],9 ; just test IF bit in EFLAGS setc al ; set AL = carry (IF flag from EFLAGS) jmp int31oknopop ; return ok, dont pop registers ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; REAL/PROTECTED MODE TRANSLATION FUNCTIONS ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;───────────────────────────────────────────────────────────────────────────── int310300: ; simulate real mode interrupt movzx ebx,bl ; get real mode INT CS:IP mov ebp,dword ptr ds:[ebx*4] ;----------------------------------------------------------------------------- int31030012: ; common to 0300h, 0301h, and 0302h mov esi,cs:codebase ; ESI = offset of PMODE_TEXT from 0 movzx ebx,word ptr es:[edi+2eh] ; EBX = SP from register structure movzx edx,word ptr es:[edi+30h] ; EDX = SS from register structure mov ax,bx ; check if caller provided stack or ax,dx jnz short @@int31030012f3 ; if yes, go on to set stack mov dx,cs:rmstacktop ; DX = SS for real mode redirection mov bx,cs:_pm_rmstacklen ; get size of real mode stack sub dx,bx ; adjust DX to next stack location cmp dx,cs:rmstackbase ; exceeded real mode stack space? jb int31fail8012 ; if yes, error 8012h mov ds:rmstacktop[esi],dx ; update ptr for possible reenterancy shl bx,4 ; adjust BX from paragraphs to bytes @@int31030012f3: lea edi,[edx*4] ; EDI -> top of real mode stack lea edi,[edi*4+ebx] lea ax,[bx-8] ; AX = top of stack parms xchg ax,ds:rmstackparmtop[esi] ; preserve and set new top of stack push ax ; parms for possible reenterancy movzx ax,byte ptr [esp+28] ; AX = AL of original INT 31h call and al,1 ; if function 0301h, AL=0, else, AL=2 xor al,1 shl al,1 sub bx,ax ; adjust BX for possible FLAGS movzx eax,cx ; EAX = length of stack parms shl eax,1 sub bx,36h ; adjust real mode SP for needed vars sub bx,ax ; adjust real mode SP for stack parms mov ds:[edi-2],ss ; store SS:ESP on real mode stack mov ds:[edi-6],esp mov ds:[edi-8],es ; store ES on real mode stack push ds ; swap DS and ES push es pop ds pop es std ; string copy backwards sub edi,10 ; copy stack parms from protected mode movzx ecx,cx ; stack to real mode stack lea esi,[esp+ecx*2+36h-2] rep movs word ptr es:[edi],word ptr ss:[esi] mov esi,[esp+2] ; ESI = offset of structure from stack mov ax,[esi+20h] ; AX = FLAGS from register structure mov es:[edi],ax ; store data for real mode return IRET cmp byte ptr [esp+30],1 ; check AL on stack for function code je short @@int31030012f4 ; if function 0301h, go on and ah,0fch ; 0300h or 0302h, clear IF and TF flag @@int31030012f4: cld ; string copy forward lea edi,[edx*4] ; EDI -> bottom of stack lea edi,[edi*4+ebx] mov ecx,8 ; copy general regs to real mode stack rep movs dword ptr es:[edi],dword ptr ds:[esi] add esi,6 ; copy FS and GS to real mode stack movs dword ptr es:[edi],dword ptr ds:[esi] mov word ptr es:[edi+8],PMODE_TEXT ; return address from call mov word ptr es:[edi+6],off @@int31030012f1 mov es:[edi+4],ax ; store FLAGS for real mode IRET maybe mov dword ptr es:[edi],ebp ; put call address to real mode stack mov ax,[esi-6] ; real mode DS from register structure mov cx,[esi-8] ; real mode ES from register structure mov si,PMODE_TEXT ; real mode target CS:IP mov di,off @@int31030012f0 db 66h ; JMP DWORD PTR, as in 32bit offset, jmp word ptr cs:pmtormswrout ; not seg:16bit offset @@int31030012f0: ; real mode INT, FAR, or IRET call popad ; load regs with call values pop fs gs iret ; go to call address @@int31030012f1: mov sp,cs:rmstackparmtop ; remove stack parameters push gs fs ds es ; store registers on stack pushf ; store flags on stack pushad cli mov ax,ss ; EAX = linear ptr to SS movzx eax,ax shl eax,4 movzx ebp,sp ; EBP = SP mov cx,[bp+2ah] ; get protected mode ES from stack mov ebx,[bp+2ch] ; get protected mode SS:ESP from stack mov dx,[bp+30h] add ebp,eax ; EBP -> stored regs on stack mov ax,SELZERO ; DS selector value for protected mode mov si,SELCODE ; target CS:EIP in protected mode mov edi,off @@int31030012f2 jmp cs:rmtopmswrout ; go back to protected mode @@int31030012f2: mov edi,cs:codebase ; restore old stack parameter length pop ds:rmstackparmtop[edi] mov edi,[esp] ; get structure offset from stack mov esi,ebp ; copy return regs from real mode mov ecx,15h ; stack to register structure cld rep movs word ptr es:[edi],word ptr ds:[esi] cmp dword ptr es:[edi+4],0 ; stack provided by caller? jne int31ok ; if yes, done now mov edi,cs:codebase ; restore top of real mode stack mov ax,cs:_pm_rmstacklen add ds:rmstacktop[edi],ax jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310301: ; call real mode FAR procedure ; same start as function 0302h ;───────────────────────────────────────────────────────────────────────────── int310302: ; call real mode IRET procedure mov ebp,dword ptr es:[edi+2ah] ; get target CS:IP from structure jmp int31030012 ; go to common code ;───────────────────────────────────────────────────────────────────────────── int310303: ; allocate real mode callback address mov bl,cs:_pm_callbacks ; CL = total number of callbacks or bl,bl ; are there any? jz int31fail8015 ; if no, error 8015h mov edx,cs:callbackbase ; EDX -> base of callbacks mov ecx,edx ; for later use @@int310303l0: cmp word ptr [edx+3],0 ; is this callback free? jz short @@int310303f0 ; if yes, allocate add edx,25 ; increment ptr to callback dec bl ; decrement loop counter jnz @@int310303l0 ; if more callbacks to check, loop jmp int31fail8015 ; no free callback, error 8015h @@int310303f0: mov bx,[esp+38] ; BX = caller DS from stack mov [edx+3],bx ; store callback parms in callback mov [edx+7],esi mov [edx+12],es mov [edx+16],edi sub edx,ecx ; DX = offset of callback shr ecx,4 ; CX = segment of callback jmp int31okdx ; return ok, with DX, CX, AX ;───────────────────────────────────────────────────────────────────────────── int310304: ; free real mode callback address cmp cx,cs:callbackseg ; valid callback segment? jne int31fail8024 ; if no, error 8024h movzx ebx,dx ; EBX = offset of callback xor ax,ax ; check if valid offset xchg dx,ax mov cx,25 div cx or dx,dx ; is there a remainder jnz int31fail8024 ; if yes, not valid, error 8024h or ah,ah ; callback index too big? jnz int31fail8024 ; if yes, not valid, error 8024h cmp al,cs:_pm_callbacks ; callback index out of range? jae int31fail8024 ; if yes, not valid, error 8024h add ebx,cs:callbackbase ; EBX -> callback mov word ptr [ebx+3],0 ; set callback as free jmp int31ok ; return ok ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; MISC FUNCTIONS ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;───────────────────────────────────────────────────────────────────────────── int310305: ; get state save/restore addresses add esp,26h ; adjust stack pop ds ; restore DS xor ax,ax ; size needed is none mov bx,PMODE_TEXT ; real mode seg of same RETF mov cx,off vxr_saverestorerm ; same offset of 16bit RETF mov si,cs ; selector of routine is this one mov edi,off vxr_saverestorepm ; offset of simple 32bit RETF jmp int31oknopop ; return ok, dont pop registers ;───────────────────────────────────────────────────────────────────────────── int310306: ; get raw mode switch addresses add esp,26h ; adjust stack pop ds ; restore DS mov si,cs ; selector of pmtorm rout is this one mov edi,cs:pmtormswrout ; offset in this seg of rout mov bx,PMODE_TEXT ; real mode seg of rmtopm rout mov cx,cs:rmtopmswrout ; offset of rout in real mode jmp int31oknopop ; return ok, dont pop registers ;───────────────────────────────────────────────────────────────────────────── int310400: ; get version add esp,26h ; adjust stack pop ds ; restore DS mov ax,100h ; return version 1.0 mov bx,3 ; capabilities mov cl,cs:processortype ; processor type mov dx,word ptr cs:picslave ; master and slave PIC values jmp int31oknopop ; return ok, dont pop registers ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; VCPI EXTENDED MEMORY FUNCTIONS ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;----------------------------------------------------------------------------- int310500vsiditoesi: ; convert handle SI:DI to ptr ESI pop bp ; pop return address test di,3 ; is handle (ptr) aligned on dword? jnz int31fail8023 ; if no, error 8023h shl esi,16 ; ESI = SI:DI mov si,di cmp esi,cs:pagetablebase ; handle too low? jb int31fail8023 ; if yes, error 8023h cmp esi,cs:pagetabletop ; handle too high? jae int31fail8023 ; if yes, error 8023h test byte ptr [esi+1],2 ; is page first in allocated block? jz int31fail8023 ; if no, error 8023h jmp bp ; return ok ;----------------------------------------------------------------------------- int310500vbxcxtoebx: ; convert BX:CX bytes to EBX pages pop bp ; pop return address shl ebx,16 ; EBX = BX:CX mov bx,cx or ebx,ebx ; check for invalid value jz int31fail8021 ; if invalid value, error 8021h add ebx,0fffh ; convert EBX to page count shr ebx,12 jmp bp ; return ok ;----------------------------------------------------------------------------- int310500vpmalloc: ; allocate physical memory block mov edi,esi ; EDI = ESI, ptr to linear block start xor ebp,ebp ; EBP = running allocated page count @@int310500vpmallocl0: mov ax,0de04h ; VCPI allocate a page call fword ptr cs:vcpi_calleip or ah,ah ; got a page? jz short @@int310500vpmallocl0f0; if yes, go on cmp ebp,1 ; allocated any pages? jc short @@int310500vpmallocdone; if no, fail immediately or byte ptr [edi-3],4 ; set last allocated page as last call int310500vfree ; free what was allocated stc ; carry set, failed jmp short @@int310500vpmallocdone ; go to done @@int310500vpmallocl0f0: or dl,7 ; set page as user/writeable/present mov [edi],edx ; store page in page table add edi,4 ; increment page table ptr inc ebp ; increment allocated page count cmp ebp,ebx ; allocated all needed pages? jb @@int310500vpmallocl0 ; if no, loop or byte ptr [esi+1],2 ; set first allocated page as first or byte ptr [edi-3],4 ; set last allocated page as last clc ; carry clear, success @@int310500vpmallocdone: mov eax,ebp ; EAX = number of pages allocated ret ; return ;----------------------------------------------------------------------------- int310500vlmalloc: ; check for linear memory block mov edi,cs:pagetablebase ; EDI = search ptr in page table mov ecx,cs:pagetabletop ; ECX = count of pages to search sub ecx,edi shr ecx,2 xor edx,edx ; EDX = largest linear block found xor eax,eax ; EAX = search unit, free entry (0) push ebx ; preserve EBX, memory requested @@int310500vlmallocl0: jecxz short @@int310500vlmallocdone ; if no more entries, done repne scas dword ptr es:[edi] ; search for first next free entry jne short @@int310500vlmallocdone ; if no more free, go on mov ebp,ecx ; EBP = current count lea ebx,[edi-4] ; EBX = start of free block repe scas dword ptr es:[edi] ; search for end of free linear block jne short @@int310500vlmallocl0f0; if previous entry not free, go on inc ebp ; previous entry free, extra one @@int310500vlmallocl0f0: sub ebp,ecx ; EBP = number of free pages in block cmp ebp,edx ; new block larger than last largest? jb @@int310500vlmallocl0 ; if no, loop mov esi,ebx ; ESI = ptr to largest block found mov edx,ebp ; size of new largest block found cmp ebp,[esp] ; block sufficient for memory request? jb @@int310500vlmallocl0 ; if no, loop @@int310500vlmallocdone: pop ebx ; restore EBX, memory requested ret ; return ;----------------------------------------------------------------------------- int310500vmalloc: ; allocate linear+physical mem block call int310500vlmalloc ; try to allocate linear memory block cmp edx,1 ; found ANY free linear area? jc short @@int310500vmallocdone ; if no, done cmp edx,ebx ; linear block enough for request? jb short @@int310500vmallocf0 ; if no, go to physical memory check call int310500vpmalloc ; try to allocate physical mem mov cl,1 ; error is not enough physical memory jmp short @@int310500vmallocdone; go to done @@int310500vmallocf0: mov ebx,edx ; only linear block size physical mem call int310500vpmalloc ; try to allocate physical memory jc short @@int310500vmallocfaillinear ; if failed, done call int310500vfree ; success, so must free block mov eax,ebx ; can allocate this much total memory stc ; carry set, failed @@int310500vmallocfaillinear: mov cl,0 ; error is not enough linear memory @@int310500vmallocdone: ret ; return ;----------------------------------------------------------------------------- int310500vfree: ; free linear+physical memory block mov edi,esi ; EDI = ESI, ptr to linear block start @@int310500vfreel0: xor ecx,ecx ; new page table entry is free (0) xchg ecx,[edi] ; swap ECX with page table entry add edi,4 ; increment page table ptr mov edx,ecx ; EDX = page table entry and dx,0f000h ; mask off low 12 bits mov ax,0de05h ; VCPI free a page call fword ptr cs:vcpi_calleip test ch,4 ; last page of block? jz @@int310500vfreel0 ; if no, loop ret ; return ;───────────────────────────────────────────────────────────────────────────── int310500v: ; VCPI get free memory information push ds ; ES = DS for VCPI malloc functions pop es mov ebx,0ffffffffh ; try to allocate an impossible amount call int310500vmalloc shl eax,12 ; returned EAX is highest possible jmp int310500xsetbuf ; put memory information in buffer ;───────────────────────────────────────────────────────────────────────────── int310501v: ; VCPI allocate memory block push ds ; ES = DS for VCPI malloc functions pop es call int310500vbxcxtoebx ; convert BX:CX bytes to EBX pages call int310500vmalloc ; try to allocate requested amount jnc short int310501vaddxnhandle ; if successful, go to done or cl,cl ; error is not enough linear memory? jz int31fail8012 ; if yes, error 8013h jmp int31fail8013 ; error is physical, error 8013h int310501vaddxnhandle: mov ecx,esi ; figure address of block from handle sub ecx,cs:pagetablebase shl ecx,10 shld ebx,ecx,16 mov di,si ; SI:DI = ESI, handle shr esi,16 mov eax,cs:vcpi_cr3 ; reload CR3 to clear TLB mov cr3,eax jmp int31oksinoax ; return ok, with SI, DI, BX, CX ;───────────────────────────────────────────────────────────────────────────── int310502v: ; VCPI free memory block call int310500vsiditoesi ; convert handle SI:DI to ptr ESI call int310500vfree ; free memory block mov eax,cs:vcpi_cr3 ; reload CR3 to clear TLB mov cr3,eax jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310503v: ; VCPI resize memory block push ds ; ES = DS for VCPI malloc functions pop es call int310500vbxcxtoebx ; convert BX:CX bytes to EBX pages call int310500vsiditoesi ; convert handle SI:DI to ptr ESI mov edi,esi ; EDI = ESI, ptr to linear block start xor ebp,ebp ; EBP = running block size in pages @@int310503vl0: add edi,4 ; increment page table ptr inc ebp ; increment block size test byte ptr [edi-3],4 ; last page of block? jz @@int310503vl0 ; if no, loop sub ebx,ebp ; EBX = change in block size jz int310501vaddxnhandle ; if no change, done jc @@int310503vf0 ; if block made smaller, just free top mov ecx,cs:pagetabletop ; ECX = count of pages to search sub ecx,edi shr ecx,2 mov edx,ecx ; EDX = current count xor eax,eax ; EAX = search unit, free entry (0) jecxz short @@int310503vf3 ; if no entries above, try below repe scas dword ptr es:[edi] ; check for free entries above block je short @@int310503vf2 ; if previous entry free, go on dec edx ; previous entry not free, minus one @@int310503vf2: sub edx,ecx ; EDX = number of free pages in block cmp edx,ebx ; enough linear memory? jb short @@int310503vf3 ; if no, try below in linear memory push esi ; preserve start of block lea esi,[esi+ebp*4] ; ESI -> start of new block for alloc call int310500vpmalloc ; try to allocate physical memory mov edi,esi ; EDI -> start of new block pop esi ; restore start of old block jc int31fail8013 ; if alloc failed, error 8013h and byte ptr [edi-3],0fbh ; clear last bit in old block end and byte ptr [edi+1],0fdh ; clear first bit in new block start jmp int310501vaddxnhandle ; go to done @@int310503vf3: mov ecx,esi ; ECX = count of pages to search up sub ecx,cs:pagetablebase shr ecx,2 or ecx,ecx ; any linear memory below? jz @@int310503vf1 ; if no, try to allocate push ebp ; preserve size of original block lea edi,[esi-4] ; EDI = ESI, ptr to linear block start mov ebp,ecx ; EBP = current count std ; search is up repe scas dword ptr es:[edi] ; check for free entries after block cld je short @@int310503vf4 ; if previous entry free, go on dec ebp ; previous entry not free, minus one @@int310503vf4: sub ebp,ecx ; EBP = number of free pages in block lea eax,[ebp+edx] ; free size below + free size above pop ebp ; restore original block size cmp eax,ebx ; enough linear memory? jb @@int310503vf1 ; if no, try to allocate push esi ; preserve original block address sub ebx,edx ; EBX = number of pages needed below lea eax,[ebx*4] ; get base of block below sub esi,eax push edx ebp ; preserve some vars call int310500vpmalloc ; try to allocate physical memory pop ebp edx ; restore some vars mov edi,esi ; EDI -> base of block below pop esi ; restore base of original block jc int31fail8013 ; if alloc failed, error 8013h or edx,edx ; any pages needed above? jz short @@int310503vf6 ; if no, go on push esi edi ebp ; preserve some vars mov ebx,edx ; EBX = size of block below lea esi,[esi+ebp*4] ; ESI -> start of block above call int310500vpmalloc ; try to allocate physical memory pop ebp edi esi ; restore some vars jnc short @@int310503vf5 ; if allocated ok, go on mov esi,edi ; ESI -> allocated block below call int310500vfree ; free allocated block below jmp int31fail8013 ; fail, error 8013h @@int310503vf5: and byte ptr [esi-3],0fbh ; clear last bit in below block end and byte ptr [esi+ebp*4+1],0fdh ; clear first bit in above block start @@int310503vf6: and byte ptr [edi+1],0fdh ; clear first bit in below block start and byte ptr [esi+ebp*4-3],0fbh ; clear last bit in old block end push edi ; preserve new block start mov edx,edi ; EDX = base of move area lea ebx,[esi-4] ; EBX = current location in move area @@int310503vl1: mov edi,ebx ; set up to shift up a page mov esi,ebx mov ecx,ebp lods dword ptr ds:[esi] ; shift old pages a page down in table rep movs dword ptr es:[edi],dword ptr ds:[esi] stos dword ptr es:[edi] sub ebx,4 ; decrement to next page to shift cmp ebx,edx ; more pages to shift? jae @@int310503vl1 ; if yes, loop pop esi ; restore new block start address jmp int310501vaddxnhandle ; go to done @@int310503vf1: add ebx,ebp ; restore EBX as requested size push esi ebp ; preserve some vars call int310500vlmalloc ; check for linear memory block pop ebp edi ; restore some vars cmp edx,ebx ; enough linear memory? jb int31fail8012 ; if no, error 8012h sub ebx,ebp ; EBX = extra pages needed push esi ; preserve for later copy lea esi,[esi+ebp*4] ; ESI -> start of extra space needed push edi ebp ; preserve some vars call int310500vpmalloc ; try to allocate physical memory pop ecx esi edi ; restore some vars jc int31fail8013 ; if not enough mem, error 8013h push edi esi ecx ; preserve, new and old block, size rep movs dword ptr es:[edi],dword ptr ds:[esi] ; copy old block pages and byte ptr [edi-3],0fbh ; clear last bit in old block end and byte ptr [edi+1],0fdh ; clear first bit in new block start pop ecx edi ; restore to clear old block xor eax,eax ; new page table entry is free (0) rep stos dword ptr es:[edi] ; clear old page table block pop esi ; restore new block address jmp int310501vaddxnhandle ; go to done @@int310503vf0: sub edi,4 ; decrement page table ptr xor edx,edx ; new page table entry is free (0) xchg edx,[edi] ; swap EDX with page table entry and dx,0f000h ; mask off low 12 bits mov ax,0de05h ; VCPI free a page call fword ptr cs:vcpi_calleip inc ebx ; increment negative change counter jnz @@int310503vf0 ; if more pages to free, loop or byte ptr [edi-3],4 ; set next page up as last of block jmp int310501vaddxnhandle ; go to done ;───────────────────────────────────────────────────────────────────────────── int31050av: ; VCPI get memory block size and base shrd ecx,esi,16 ; figure address of block from handle mov cx,di sub ecx,cs:pagetablebase shl ecx,10 shld ebx,ecx,16 call int310500vsiditoesi ; convert handle SI:DI to ptr ESI xor edi,edi ; EDI = running page count @@int31050avl0: inc edi ; increment page count lods dword ptr ds:[esi] ; EAX = page table entry test ah,4 ; is this the last page of the block? jz @@int31050avl0 ; if no, loop shl edi,12 ; convert EDI pages to bytes shld esi,edi,16 ; SI:DI = EDI, size in bytes jmp int31oksinoax ; return ok, with SI, DI, BX, CX ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; XMS EXTENDED MEMORY FUNCTIONS ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;----------------------------------------------------------------------------- int310500xsetbuf: mov es,[esp+24h] ; get ES:EDI buffer ptr from stack mov edi,[esp] stos dword ptr es:[edi] ; store block size in output buffer mov ecx,0bh ; fill rest of buffer with 0ffffffffh mov eax,0ffffffffh rep stos dword ptr es:[edi] jmp int31ok ; return ok ;----------------------------------------------------------------------------- int310500xcallxms: ; make a all to real mode XMS driver pop bp ; pop return address sub esp,32h ; stack space for register structure mov [esp+1ch],ax ; put AX in register structure mov [esp+10h],bx ; put BX in register structure mov [esp+18h],cx ; put CX in register structure mov [esp+14h],dx ; put DX in register structure mov word ptr [esp+20h],0 ; zero FLAGS in register structure mov dword ptr [esp+2eh],0 ; zero SS:SP in register structure mov eax,dword ptr cs:xms_callip ; put XMS driver address in CS:IP in mov [esp+2ah],eax ; regis]er structure push ss ; ES:EDI -> register structure pop es mov edi,esp xor cx,cx ; copy 0 words as stack parameters xor bh,bh ; doesnt really need to be here mov ax,301h ; call real mode FAR procedure int 31h mov ax,[esp+1ch] ; get AX from register structure mov bx,[esp+10h] ; get BX from register structure mov cx,[esp+18h] ; get CX from register structure mov dx,[esp+14h] ; get DX from register structure lea esp,[esp+32h] ; adjust ESP without changing FLAGS jc int31fail8010 ; if INT 31h failed, error 8010h jmp bp ; return ok ;----------------------------------------------------------------------------- int310500xbxcxtodx: ; convert BX:CX bytes to DX K pop bp ; pop return address mov dx,cx ; check for invalid value, BX=CX=0 or dx,bx jz int31fail8021 ; if invalid value, error 8021h add cx,1023+15 ; adjust for size in K and align adc bx,0 test bh,0fch ; memory request too high jnz int31fail8013 ; if yes, error 8013h shrd cx,bx,10 ; CX = memory in K mov dx,cx jmp bp ; return ok ;----------------------------------------------------------------------------- int310500xerror: ; XMS error, return with DPMI error cmp bl,0a0h ; out of memory? je int31fail8013 ; if yes, error 8013h cmp bl,0a1h ; handles exhausted? je int31fail8016 ; if yes, error 8016h cmp bl,0a2h ; invalid handle? je int31fail8023 ; if yes, error 8023h jmp int31fail8010 ; else, error 8010h ;───────────────────────────────────────────────────────────────────────────── int310500x: ; XMS get free memory information mov ah,8 ; get largest free memory block in K call int310500xcallxms movzx eax,ax ; EAX = free memory in bytes shl eax,10 sub eax,15 ; adjust by extra alignment size jnc int310500xsetbuf ; if no overflow, put info to buffer xor eax,eax ; overflow, so no memory available jmp int310500xsetbuf ; put memory information in buffer ;───────────────────────────────────────────────────────────────────────────── int310501x: ; XMS allocate memory block call int310500xbxcxtodx ; convert BX:CX bytes to DX K mov cx,dx ; preserve size of block in K mov ah,9 ; allocate DX K of XMS memory call int310500xcallxms or ax,ax ; error? jz int310500xerror ; if yes, convert XMS error to DPMI mov si,dx ; get DPMI handle from XMS handle int310501xgotmem: mov ah,0ch ; lock memory block call int310500xcallxms or ax,ax ; error? jnz short @@int310501xf0 ; if no, go on push bx ; yup, preserve error number mov ah,0ah ; free block causing lock error call int310500xcallxms pop bx ; restore error number jmp int310500xerror ; XMS error, return with DPMI error @@int310501xf0: mov di,cx ; low word of DPMI handle is size in K mov cx,bx ; XMS linear address to DPMI regs mov bx,dx add cx,0fh ; align linear address on paragraph adc bx,0 and cl,0f0h jmp int31oksinoax ; return ok, with SI, DI, BX, CX ;───────────────────────────────────────────────────────────────────────────── int310502x: ; XMS free memory block mov dx,si ; get XMS handle from DPMI handle mov ah,0dh ; unlock memory block call int310500xcallxms or ax,ax ; error? jz int310500xerror ; if XMS error, return with DPMI error mov ah,0ah ; free memory block call int310500xcallxms or ax,ax ; error? jz int310500xerror ; if yes, convert XMS error to DPMI jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310503x: ; XMS resize memory block call int310500xbxcxtodx ; convert BX:CX bytes to DX K mov cx,dx ; preserve size of block in K mov dx,si ; get XMS handle from DPMI handle mov ah,0dh ; unlock memory block call int310500xcallxms or ax,ax ; error? jz int310500xerror ; if XMS error, return with DPMI error mov bx,cx ; BX = new size in K mov ah,0fh ; resize memory block call int310500xcallxms mov dx,si ; get XMS handle again or ax,ax ; error in resize? jnz int310501xgotmem ; if no, go to memory block code push bx ; yup, preserve error number mov ah,0ch ; lock memory block call int310500xcallxms pop bx ; restore error number jmp int310500xerror ; XMS error, return with DPMI error ;───────────────────────────────────────────────────────────────────────────── int31050ax: ; XMS get memory block size and base mov dx,si ; get XMS handle from DPMI handle mov si,di ; SI = size of block in K mov ah,0dh ; unlock memory block call int310500xcallxms or ax,ax ; error? jz int310500xerror ; if XMS error, return with DPMI error mov ah,0ch ; lock memory block call int310500xcallxms or ax,ax ; error? jz int310500xerror ; if XMS error, return with DPMI error xor di,di ; convert size in K to size in bytes shrd di,si,6 shr si,6 mov cx,bx ; XMS linear address to DPMI regs mov bx,dx mov ax,cx ; figure out alignment stub dec ax and ax,0fh xor al,0fh sub di,ax ; subtract alignment stub from size sbb si,0 add cx,0fh ; align linear address on paragraph adc bx,0 and cl,0f0h jmp int31oksinoax ; return ok, with SI, DI, BX, CX ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ; RAW EXTENDED MEMORY FUNCTIONS ;▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒▒ ;----------------------------------------------------------------------------- int310500rnomem: ; no free extended memory present xor eax,eax ; 0 available extended memory jmp int310500xsetbuf ; put memory information in buffer ;----------------------------------------------------------------------------- int310500rbxcxtoebx: ; convert BX:CX bytes to EBX bytes pop bp ; pop return address shl ebx,16 ; EBX = BX:CX mov bx,cx or ebx,ebx ; check for invalid value jz int31fail8021 ; if invalid value, error 8021h add ebx,0fh ; align EBX on paragraph and bl,0f0h jmp bp ; return ok ;----------------------------------------------------------------------------- int310500rfindmcb: ; find MCB for handle SI:DI pop bp ; pop return address shl esi,16 ; ESI = handle SI:DI = address of MCB mov si,di mov edi,cs:rawextmemtop ; EDI -> first memory control block @@int310500rfindmcbl0: cmp edi,esi ; found MCB? jne short @@int310500rfindmcbl0f0 ; if no, keep looking cmp byte ptr [edi-4],0 ; memory block free? je int31fail8023 ; if yes, error 8023h jmp bp ; return ok, found MCB @@int310500rfindmcbl0f0: mov edi,[edi-12] ; EDI -> next memory control block or edi,edi ; is there another MCB? jnz @@int310500rfindmcbl0 ; if yes, loop jmp int31fail8023 ; fail, error 8023h ;----------------------------------------------------------------------------- int310500radjustused: ; adjust INT 15h extended memory used mov eax,cs:rawextmemtop ; EAX -> first memory control block @@int310500radjustusedl0: cmp dword ptr [eax-12],0 ; last memory control block? jz short @@int310500radjustusedf0 ; if yes, go to set new used K mov eax,[eax-12] ; EAX -> next memory control block jmp @@int310500radjustusedl0 ; loop @@int310500radjustusedf0: cmp byte ptr [eax-4],0 ; memory block free? je short @@int310500radjustusedf1 ; if no, go on sub eax,[eax-16] ; used, adjust by size of block @@int310500radjustusedf1: sub eax,10h ; adjust by size of MCB and eax,0fffffc00h ; align on K sub eax,cs:rawextmemtop ; size of extended memory used neg eax shr eax,10 ; convert from bytes to K mov ebp,cs:codebase ; EBP = offset of PMODE_TEXT from 0 mov ds:rawextmemused[ebp],ax ; adjust INT 15h extended memory used @@int310500radjustuseddone: ret ; return ;----------------------------------------------------------------------------- int310500rlinkmcb: ; link memory blocks at ESI and EDI mov eax,[esi-16] ; combine two block sizes add eax,10h add [edi-16],eax ; add size of next block to this one mov ecx,[esi-12] ; copy next MCB field mov [edi-12],ecx jecxz short @@int310500rlinkmcbf0 ; if no next MCB, done mov [ecx-8],edi ; set prev MCB in next MCB to this MCB @@int310500rlinkmcbf0: ret ; return ;───────────────────────────────────────────────────────────────────────────── int310500r: ; raw get free memory information mov edi,cs:rawextmemtop ; EDI -> first memory control block xor eax,eax ; running highest free memory block @@int310500rl0: cmp byte ptr [edi-4],0 ; is block free? jne short @@int310500rl0f0 ; if no, loop mov ebx,[edi-16] ; EBX = size of block cmp eax,ebx ; last free block larger? ja short @@int310500rl0f0 ; if yes, loop mov eax,ebx ; found larger block, new largest @@int310500rl0f0: mov edi,[edi-12] ; EDI -> next memory control block or edi,edi ; is there another MCB? jnz @@int310500rl0 ; if yes, loop jmp int310500xsetbuf ; put memory information in buffer ;───────────────────────────────────────────────────────────────────────────── int310501r: ; raw allocate memory block call int310500rbxcxtoebx ; convert BX:CX bytes to EBX bytes mov edi,cs:rawextmemtop ; EDI -> first memory control block @@int310501rl0: cmp byte ptr ds:[edi-4],0 ; is block free? je short @@int310501rl0f2 ; if yes, check block @@int310501rl0f0: mov edi,[edi-12] ; EDI -> next memory control block or edi,edi ; is there another MCB? jnz @@int310501rl0 ; if yes, loop jmp int31fail8013 ; fail, error 8013h @@int310501rl0f2: lea ecx,[edi-10h] ; ECX -> possible new MCB sub ecx,ebx mov eax,[edi-16] ; EAX = size of block sub eax,ebx ; enough free memory in block? jc short @@int310501rl0f0 ; if no, loop jz short @@int310501rl0f1 ; if exactly same size, continue sub eax,10h ; adjust for size of new created MCB mov [ecx-16],eax ; put size of new block in new MCB mov eax,ecx ; set next MCB in old MCB as new one xchg [edi-12],eax ; copy next MCB from old to new MCB mov [ecx-12],eax or eax,eax ; is there a next MCB? jz short @@int310501rl0f3 ; if no, go on mov [eax-8],ecx ; set prev MCB in next MCB to new MCB @@int310501rl0f3: mov [ecx-8],edi ; set prev MCB in new MCB as old one mov byte ptr [ecx-4],0 ; set new MCB as free mov [edi-16],ebx ; set size of allocated block @@int310501rl0f1: mov byte ptr [edi-4],1 ; set block as allocated int310501raddxnhandle: shld ebx,ecx,16 ; BX:CX = ECX, address of block shld esi,edi,16 ; SI:DI = EDI, handle (address of MCB) call int310500radjustused ; adjust INT 15h extended memory used jmp int31oksinoax ; return ok, with SI, DI, BX, CX ;───────────────────────────────────────────────────────────────────────────── int310502r: ; raw free memory block call int310500rfindmcb ; find MCB for handle SI:DI mov byte ptr [edi-4],0 ; set this memory block as free mov esi,[edi-12] ; ESI -> next memory control block or esi,esi ; is there next MCB? jz short @@int310502rf0 ; if no, go on cmp byte ptr [esi-4],0 ; is next memory block free? jne short @@int310502rf0 ; if no, go on call int310500rlinkmcb ; link two memory blocks @@int310502rf0: mov esi,[edi-8] ; ESI -> previous memory control block or esi,esi ; is there previous MCB? jz short @@int310502rf1 ; if no, go on cmp byte ptr [esi-4],0 ; is previous memory block free? jne short @@int310502rf1 ; if no, go on xchg esi,edi ; change mcb order for function call int310500rlinkmcb ; link two memory blocks @@int310502rf1: call int310500radjustused ; adjust INT 15h extended memory used jmp int31ok ; return ok ;───────────────────────────────────────────────────────────────────────────── int310503r: ; raw resize memory block call int310500rbxcxtoebx ; convert BX:CX bytes to EBX bytes mov edx,ebx ; EDX = size of new block call int310500rfindmcb ; find MCB for handle SI:DI push ds ; ES = DS for possible block copy pop es sub ebx,[esi-16] ; EBX = change in block size jz @@int310503rf0 ; if no change, done jc @@int310503rf1 ; if block made smaller, just free top xor eax,eax ; running memory counter mov ecx,[esi-12] ; ECX -> next MCB jecxz short @@int310503rf4 ; if no next MCB, check previous MCB cmp byte ptr [ecx-4],0 ; next MCB free? jne short @@int310503rf4 ; if not, check previous MCB mov eax,[ecx-16] ; EAX = amount of free memory in block add eax,10h ; including memory control block @@int310503rf4: mov ecx,[esi-8] ; ECX -> previous MCB jecxz short @@int310503rf5 ; if no previous MCB, check memory cmp byte ptr [ecx-4],0 ; previous MCB free? jne short @@int310503rf5 ; if not, check memory add eax,[ecx-16] ; add amount of free memory in block add eax,10h ; including memory control block @@int310503rf5: cmp eax,ebx ; enough to resize within area jb @@int310503rf3 ; if no, try to allocate or ecx,ecx ; is there a previous MCB? jz @@int310503rf6 ; if no, resize to next cmp byte ptr [ecx-4],0 ; previous MCB free? jne short @@int310503rf6 ; if not, resize to next mov ebp,[ecx-16] ; EBP = size of previous block, try to add ebp,10h ; resize within previous block sub ebp,ebx ; EBP = prev block size - needed size jbe short @@int310503rf7 ; if prev block too small, go on mov edi,ecx ; EDI -> new MCB for new memory block sub edi,ebp ; resize will fit entirely lea eax,[ebp-10h] ; EAX = new size of free block mov [ecx-16],eax ; store mew free size in prev MCB mov [edi-16],edx ; store new size in new MCB mov [ecx-12],edi ; set next MCB in prev MCB to new MCB mov [edi-8],ecx ; set prev MCB in new MCB to prev MCB mov byte ptr [edi-4],1 ; set new MCB as used mov ecx,[esi-12] ; copy next MCB field mov [edi-12],ecx or ecx,ecx ; is there a next MCB jz @@int310503rf0 ; if no, go to block readjust mov [ecx-8],edi ; set prev MCB in next MCB to new MCB jmp @@int310503rf0 ; go to block readjust @@int310503rf7: mov edi,ecx ; EDI -> new MCB for new memory block lea eax,[edx+ebp] ; EAX = size of new block mov [edi-16],eax ; store mew free size in new MCB mov byte ptr [edi-4],1 ; set new MCB as used mov ecx,[esi-12] ; copy next MCB field mov [edi-12],ecx jecxz short @@int310503rf8 ; if no next MCB, go on mov [ecx-8],edi ; set prev MCB in next MCB to new MCB @@int310503rf8: add ebp,ebx ; EBP = size of block just acquired sub ebx,ebp ; EBX = new size still needed jz @@int310503rf0 ; if no more space needed, done mov esi,edi ; ESI -> new MCB @@int310503rf6: mov edi,[esi-12] ; EDI -> next MCB mov ecx,[edi-12] ; copy next MCB field mov [esi-12],ecx jecxz short @@int310503rf9 ; if no next MCB, go on mov [ecx-8],esi ; set prev MCB in next MCB to this MCB @@int310503rf9: mov eax,[edi-16] ; EAX = size of next memory block add eax,10h sub edi,eax ; EDI -> start of next memory block sub eax,ebx ; EAX = amount of free space left mov ecx,[esi-16] ; ECX = old size of this memory block mov [esi-16],edx ; store new size in this MCB mov byte ptr [esi-4],1 ; set this MCB as used sub esi,ecx ; ESI -> start of this memory block sub esi,10h shr ecx,2 ; copy this memory block down in mem rep movs dword ptr es:[edi],dword ptr ds:[esi] add esi,10h ; adjust ESI to top MCB mov edi,esi ; EDI -> top MCB mov ebx,eax ; EBX = negative of space free at top neg ebx jz @@int310503rf0 ; in no space free, go to done jmp short @@int310503rf1 ; set new MCBs for moved block @@int310503rf3: mov ebp,edi ; preserve old block MCB address sub edx,ebx ; EDX = size of old block mov bx,[esp+16] ; BX:CX = new block size from stack mov cx,[esp+24] mov ax,501h ; try to allocate new block int 31h jc int31failax ; if could not, fail with error AX shrd eax,esi,16 ; EAX -> new block MCB mov ax,di shrd edi,ebx,16 ; EDI -> start of new block mov di,cx lea esi,[ebp-10h] ; ESI -> start of old block sub esi,edx mov ecx,edx ; copy memory from old block to new shr ecx,2 rep movs dword ptr es:[edi],dword ptr ds:[esi] mov edx,eax ; EDX -> new block MCB shld esi,ebp,16 ; SI:DI = handle of old block mov di,bp mov ax,0502h ; free old block int 31h mov edi,edx ; EDI -> new block MCB for done jmp short @@int310503rf0 ; go to done @@int310503rf1: lea edi,[esi+ebx] ; EDI -> new MCB for new memory block lea eax,[ebx+10h] ; EAX = size of freed block neg eax mov [esi-16],eax ; store freed size in old MCB mov [edi-16],edx ; store new size in new MCB mov ecx,[esi-12] ; copy next MCB field mov [edi-12],ecx jecxz short @@int310503rf2 ; if no next MCB, go on mov [ecx-8],edi ; set prev MCB in next MCB to new MCB @@int310503rf2: mov [esi-12],edi ; set next MCB in old MCB as new MCB mov [edi-8],esi ; set prev MCB in new MCB as old MCB mov byte ptr [edi-4],1 ; set new MCB as used mov byte ptr [esi-4],0 ; set old MCB as free mov ecx,[esi-8] ; ECX -> prev MCB of old MCB jecxz short @@int310503rf0 ; if no prev MCB, done cmp byte ptr [ecx-4],0 ; is previous MCB free? jne short @@int310503rf0 ; if no, dont link push edi ; preserve new MCB mov edi,ecx ; top MCB = prev MCB for link function call int310500rlinkmcb ; link two memory blocks pop edi ; restore new MCB @@int310503rf0: mov ecx,[edi-16] ; ECX = base address of new block neg ecx lea ecx,[ecx+edi-10h] jmp int310501raddxnhandle ; return address and handle ;───────────────────────────────────────────────────────────────────────────── int31050ar: ; raw get memory block size and base call int310500rfindmcb ; find MCB for handle SI:DI mov edi,[esi-16] ; EDI = size of memory block lea ecx,[esi-10h] ; get base address of memory block sub ecx,edi shld ebx,ecx,16 ; BX:CX = ECX, address of block shld esi,edi,16 ; SI:DI = EDI, size of memory block jmp int31oksinoax ; return ok, with SI, DI, BX, CX PMODE_TEXT ends end