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Assembly Source File | 1993-10-17 | 47.2 KB | 1,710 lines

COMMENT $ DOS32 Version 1.2 A 32 bit MSDOS extender for assembly programmers supporting Dos Protected Mode Interrupt Specification and System BIOS extended memory copy service (INT 15h AH = 87h) for without DPMI. Unlike Version 1.0 this uses the only one protected mode segment. i.e Does not have a seperate code ,data and stack descriptor base addresses. A much better way to program Written by Adam Seychell SEP-1993 email s921880@minyos.xx.rmit.oz.au $ .SEQ .386p ; Enable "REAL" CPU instuctions. V86_stack_size equ 200h ; Size of stack for V86 interrupt calls PIC_Base equ 80h ; Base interrupt address for the 8259s ; ; Format of a 386DX TSS (Task State Segment) ; TSS struc tss_prev dw 0 ,0 ; back link to previous TSS tss_esp0 dd 0 ; Priv. 0 ESP tss_ss0 dw 0 ; Priv. 0 SS dw 0 ; unused tss_esp1 dd 0 ; Priv. 1 ESP tss_ss1 dw 0 ; Priv. 1 SS dw 0 ; unused tss_esp2 dd 0 ; Priv. 2 ESP tss_ss2 dw 0 ; Priv. 2 SS dw 0 ; unused tss_cr3 dd 0 ; PDBR tss_eip dd 0 tss_eflags dd 0 tss_eax dd 0 tss_ecx dd 0 tss_edx dd 0 tss_ebx dd 0 tss_esp dd 0 tss_ebp dd 0 tss_esi dd 0 tss_edi dd 0 tss_es dw 0,0 tss_cs dw 0,0 tss_ss dw 0,0 tss_ds dw 0,0 tss_fs dw 0,0 tss_gs dw 0,0 tss_ldt dw 0,0 tss_t dw 0 ; if bit 0 set, exception on tsk switch tss_iobase dw 068h ; points to beg. of I/O permissions map tss_iomap db 2000h dup (0) ; I/O permissions bit map tss_ioend db 11111111b ; I/O map trailer TSS_ENDS equ $ - TSS tss ends Data_sruct struc C_EDI dd 0 C_ESI dd 0 C_EBP dd 0 C_resrved dd 0 C_EBX dd 0 C_EDX dd 0 C_ECX dd 0 C_EAX dd 0 C_FLAGS dw 0 C_ES dw 0 C_DS dw 0 C_FS dw 0 C_GS dw 0 C_IP dw 0 C_CS dw 0 C_SP dw 0 C_SS dw 0 ends DOS_CODE SEGMENT PUBLIC 'CODE' USE16 assume CS:DOS_CODE , DS:DOS_CODE , FS:CODE32 s_ACCESS record d_P:1,d_DPL:2,s_S:1,d_TYPE:4 s_INFO record d_G:1,d_D:1,d_nul:1,d_avl:1,d_lim:4 align 8 GDT dd 0,0 ; First descriptor is always NULL. ; Data DESCRIPTOR for a FLAT memory model Flat_Data_Desc dw 0ffffh ; Limit[15..0] db 0,0,0 ; Base[23..0] s_ACCESS <1,00b,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <1,1,0,0,0fh> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] ; Code DESCRIPTOR for a FLAT memory model Flat_CODE32_Desc dw 0ffffh ; Limit[15..0] db 0,0,0 ; Base[23..0] s_ACCESS <1,00,1,1010b> ; P,DPL,1,type[E=1,C,R,A ] s_INFO <1,1,0,0,0fh> ; G,D,0,avl,Limit[19..16] db 0 ; Base[31..24] ; Data DESCRIPTOR for the free extented memory block XMS_Desc dw 0000h ; Limit[15..0] db 00,00,10h ; Base[23..0] s_ACCESS <1,00b,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <1,1,0,0,00h> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] ; Data DESCRIPTOR with base = start of free base memory BASE_Desc dw 0ffffh ; Limit[15..0] db ?,?,? ; Base[23..0] s_ACCESS <1,00,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <0,1,0,0,0fh> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] ; Data DESCRIPTOR with base = 0A0000h Video_Desc dw 0ffffh ; Limit[15..0] db 00,00,0Ah ; Base[23..0] s_ACCESS <1,00,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <0,1,0,0,01h> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] ; 16bit data and code DESCRIPTORS for real mode ( DOS ) DOS_Code_Desc dw 0ffffh ; Limit[15..0] db ?,?,? ; Base[23..0] s_ACCESS <1,00,1,1010b> ; P,DPL,1,type[E=1,C,R,A ] s_INFO <0,0,0,0,00h> ; G,D,0,avl,Limit[19..16] db 0 ; Base[31..24] Dos_Data_Desc dw 0ffffh ; Limit[15..0] db ?,?,? ; Base[23..0] s_ACCESS <1,00,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <0,0,0,0,0h> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] ; Data PSP Descr with base = PSP , limit = 100h PSP_desc dw 0ffh ; Limit[15..0] db 00,00,00h ; Base[23..0] s_ACCESS <1,00,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <0,0,0,0,00h> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] ; Data Descr for program ENVIRONMENT ENVIRONMENT_desc dw 0ffh ; Limit[15..0] db 00,00,00h ; Base[23..0] s_ACCESS <1,00,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <0,0,0,0,0h> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] ; DATA and CODE DESCRIPTORS for your dos extender CODE32_Desc dw 0ffffh ; Limit[15..0] db ?,?,? ; Base[23..0] s_ACCESS <1,00,1,1010b> ; P,DPL,1,type[E=1,C,R,A ] s_INFO <0,1,0,0,0fh> ; G,D,0,avl,Limit[19..16] db 0 ; Base[31..24] Data_Desc dw 0ffffh ; Limit[15..0] db ?,?,? ; Base[23..0] s_ACCESS <1,00b,1,0010b> ; P,DPL,1,type[E=0,ED,W,A ] s_INFO <0,1,0,0,0fh> ; G,B,0,avl,Limit[19..16] db 0 ; Base[31..24] MyMain_TSS_Desc dw TSS_ends ; Limit[15..0] db ?,?,? ; Base[23..0] s_ACCESS <1,00,0,09h> ; P,DPL,0,(type = avalible 386 TSS ) s_INFO <0,0,0,0,00h> ; G,0,0,0,Limit[19..16] db 0 ; Base[31..24] GDT_ends equ $ - GDT ;======== ERROR MESSAGES FOR PROGRAM TERMINATION IN NON-DPMI =============== unknown_int_exit_mesg db 'Exited from Unhandled protected mode interrupt',10,13,36 _V86_illigal_err db 10,13,' Invalid Instuction in V86 mode ',10,13,36 _exit_errror db 10,10,' PROGRAM TERMINATED ',10,13,7,36 e_0 db '0 Divide error',10,13,36 e_1 db '1 Debug exception',10,13,36 e_2 db '2 Non-Maskable interrupt',10,13,36 e_3 db '3 Breakpoint',10,13,36 e_4 db '4 Overflow',10,13,36 e_5 db '5 Range Exceeded',10,13,36 e_6 db '6 Invalid opcode',10,13,36 e_7 db '7 No math unit avalible',10,13,36 e_8 db '8 Reserved',10,13,36 e_9 db '9 Reserved',10,13,36 e_10 db '10 Invalid TSS',10,13,36 e_11 db '11 Segment Not Present',10,13,36 e_12 db '12 Stack exception',10,13,36 e_13 db '13 General Protection Exception',10,13,36 e_14 db '14 Page fault',10,13,36 e_15 db '14 Reserved',10,13,36 DOS_IDT_value dw 03ffh,0,0,0 DPMI_entry dw 0,0 xms_usage_tmp dd 0 _tmpL_xms_base dw 0 _tmpH_xms_base dw 0 xms_driver dd 0 XMS_handle dw 0,0 oirqMask db 0,0 DPMI_Selector dw 0 PIC1_Base db 0 PIC2_Base db 0 ;---------------------------------------------------------------------------- ;───────────────────── INTERNALY USED ROUTINES ─────────────────────────────────── ;---------------------------------------------------------------------------- ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· Exit_Error: mov ah,9 ; Prints error mesage and terminates int 21h call free_XMS_memory mov ah,4ch int 21h ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· free_XMS_memory proc near cmp [xms_driver],0 jz No_xms_driver ; UNLOCK THE ALLOCATED EXTENDED MEMORY BLOCK mov ah,0Dh mov dx,[XMS_handle] call [XMS_Driver] ; FREE ALLOCATED BLOCK MOV AH,0Ah mov dx,[XMS_handle] call [xms_driver] No_xms_driver: RET free_XMS_memory endp ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;───────────────────────────────────────────────────────────────────────────── ; Set new IRQ vector numbers set_8259intvec proc ; Set IRQ vectors 0..7 to bl ; and IRQ vectors 8..15 to bh CLI ;∙·∙·∙·∙·∙·∙· set first 8259A PIC ∙·∙·∙·∙·∙·∙· mov al,00010001b ;ICW1 out 20h,al ;icw4 is needed call Delay8259 mov al,bl ;ICW2 out 21h,al ;( Set PIC 1 Base interrupt number ) call Delay8259 mov al,4h ;ICW3 out 21h,al call Delay8259 mov al,1h ;ICW4 out 21h,al call Delay8259 ;∙·∙·∙·∙·∙·∙· set second 8259A PIC ∙·∙·∙·∙·∙·∙· mov al,00010001b ;ICW1 out 0a0h,al ;icw4 is needed call Delay8259 mov al,bh ;ICW2 out 0a1h,al ;( Set PIC 2 Base interrupt number ) call Delay8259 mov al,00000010b ;ICW3 out 0a1h,al call Delay8259 mov al,0000001b ;ICW4 out 0a1h,al call Delay8259 ret delay8259: mov ax,1000h @3del: dec ax jnz @3del ret ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;───────────────────────────────────────────────────────────────────────────── endp Go_REAL_MODE proc near ;───────────────────────────────────────────────────────────────────────────── ; Entry point to exit protected mode and restore hardware configeration. ; Then exits back to MSDOS. ( only for non-DPMI ) ;───────────────────────────────────────────────────────────────────────────── cli mov al,00110100b ; SLOW DOWN TIMER FOR POOR OLD DOS out 43h,al XOR AL,AL out 40h,al out 40h,al ; Exit protected mode and return to DOS ; Load Data registers with 8086 SEGMENTs (Fields B=0 and D=0 of descriptors) mov ax,DOS_Data_Desc - GDT mov ss,ax mov es,ax mov ds,ax mov fs,ax mov gs,ax lidt qword ptr DOS_IDT_value ; Set IDT to how DOS want's it ; Exit protecded mode mov eax,CR0 and al,NOT 1 ;Clear PE bit mov CR0,eax db 0eah dw To_MSDOS , Dos_CODE ; reload CS:IP with real mode values To_MSDOS: ;-- remap IRQ int vectors --- mov bl,008h mov bh,070h call set_8259intvec assume ds:dos_code mov ax,dos_code mov ds,ax mov ax,V86_STACK ; Set up a bit of stack just to exit mov ss,ax mov esp,100h mov al,oirqMask ; return origonal values of the IRQ mask bits out 21h,al mov al,oirqMask+1 out 0A1h,al mov al,20h ; Send PIC acknoledge out 20h,al out 0a0h,al in al,60h ; do a keyboard read to get out of buffer ; just in case program exits without so cmp ebp,'ERRA' jnz normal_terminate ; Print error message if need to push dx mov ax,3 ; Want to exit in text mode int 10h pop dx mov ah,9 int 21h mov dx,offset _exit_errror int 21h normal_terminate: call free_XMS_memory ; deallocated XMS Exit_To_MSDOS: mov ax,4C00h ; Finaly get back to MSDOS in real mode. int 21h assume ds:dos_code endp ;---------------- finished exiting routine ------------------------- align 16 NON_DPMI_initalize_start: GDTR_value dw GDT_ends - 1 dd offset GDT IDTR_value dq 0000000007ffh Label InterruptGATE_a dword dw offset exception ; Offset[15..0] dw CODE32_Desc - GDT ; Selector Label InterruptGATE_b dword db 00000000b ; 0,0,0,WordCnt[4..0] s_ACCESS <1,00b,0,0Eh> ; P,DPL,0,type = 386 interrupt Gate dw 0 ; Offset[31..16] ;═════════════════ INITALIZATION ERROR MESSAGES ════════════════════════════ _inV86_err db ' Unable to enter protected mode because another protected mode ',10,13 db 'application is operating and does not support Dos Protected Mode Interface',10,13 db 'specifiaction.',10,13,10 db ' Disable the protected mode sofware and try again.',10,13,36 mesg_TimeOut8042 db 'Time out error in the keyboard controller (8042) failing to ',10,13 db ' respond on enabling the A20 gate.',10,13 all_DPMI_err db 'Encountered DPMI error: ',36 pmiERr db 'Switching to protecded mode.',10,13,36 No_Mem_err db 'Not Enough Base memory. 6000 bytes needed.',10,13,36 erralc_mesg db 'Can''t allocate descriptors.',10,13,36 errset_mesg db 'Can''t Set descriptors.',10,13,36 dpmi_aloc_err db 'Can''t allocate extended memory.',10,13,36 dpmi_lock_err db 'Unable to lock allocated memory.',10,13,36 dpmi_free_err db 'Unable to get free memory information.',10,13,36 mesgA20_err db 'ERROR: Physical A20 gate test failed.',10,13,36 xms_mesgA20_err db 'ERROR: XMS enabling the A20 gate.',10,13,36 ;xms_vers_err db 'Need XMS v3.0 or greater.',10,13,36 xms_alloc_Err db 'Can''t allocate XMS memory.',10,13,36 xms_lock_err db 'Can''t lock allocated XMS memory.',10,13,36 wrongCPU_mseg db ' CPU was found but sorry to say, a 386 or higher needed',10,13,36 got_286_mesg db '80286$' got_8086_mesg db '8086$' CALL_DATA Data_sruct <> .8086 ;========================================================================= ; START OF THE DOS EXTENDER ;========================================================================= DosStart proc mov ax,DOS_CODE mov ds,ax ;========= make sure we running on a 386 or higher ============= ; ; Bits 12-15 are always set on the 8086 ; pushf ; save flags pop bx ; into BX mov ax,0fffh ;clear bits 12-15 and ax,bx push ax ; put new flags value onto stack popf pushf pop ax and ax,0f000h cmp ax,0f000h ; if ax = 0f000h then it's a 8086 mov dx,offset got_8086_mesg jz Not_a_386 ; ; Bits 12-15 are always clear on the 80286 ; or bx,0f000h ; try setting bits 12-15 push bx popf pushf pop ax and ax,0f000h mov dx,offset got_286_mesg jnz Have_a_386_and_above Not_a_386: mov ah,9 int 21H mov dx,offset wrongCPU_mseg jmp exit_error .386p Have_a_386_and_above: mov ax,CODE32 mov fs,ax mov fs:[psp_segment],ES ; store psp_segment ; DOS loads from bottom to top, thus the end location of this program ; up to 9ffffh is free memory.) ; Get end of program address segment from the stack segment addrress mov bx,SP shr bx,4 inc bx mov ax,SS add bx,ax mov FS:Base_Segment,bx ; store this ending address ; SET GLOBAL DISCRIPTOR TABLE BASE ADDRESSES ; ===== Set the 32bit CODE & DATA descriptor base address ========== mov eax,CODE32 shl eax,4 mov word ptr [CODE32_desc +2 ],ax mov word ptr [DATA_desc +2 ],ax shr eax,16 mov byte ptr [CODE32_desc +4 ],al mov byte ptr [DATA_desc + 4 ],al ; ===== Set the DOS CODE & DATA descriptor base address ========== mov eax,DOS_CODE shl eax,4 mov word ptr [DOS_CODE_desc +2 ],ax mov word ptr [DOS_DATA_desc +2 ],ax shr eax,16 mov byte ptr [DOS_CODE_desc +4 ],al mov byte ptr [DOS_DATA_desc + 4 ],al ; ===== Set the program segment prefix base address ========== xor eax,eax mov ax,fs:[psp_segment] shl eax,4 mov word ptr [PSP_desc +2 ],ax shr eax,16 mov byte ptr [PSP_desc+ 4 ],al ; ===== Set the PROGRAM ENVIRONMENT base address ========== xor eax,eax mov ax,es:[2Ch] shl eax,4 mov word ptr [ENVIRONMENT_desc +2 ],ax shr eax,16 mov byte ptr [ENVIRONMENT_desc+ 4 ],al ;------------------------- A 2 0 G A T E ------------------------------- ; ENABLE THE A20 GATE ; If a XMS Driver is installed then use the Driver to enable the A20 ; If it's done directly (with 8042) ,the XMS Driver will not have ; track of the A20 state and usualy ends up hanging the system. ; ;----------------------------------------------------------------------------- ; Look for XMS driver installation mov ax,4300h int 2fh cmp al,80h jnz No_XMS ; ELSE A XMS Driver is installed push ES mov ax,4310h ; get Driver entry point int 2fh mov word ptr xms_Driver,bx mov word ptr xms_Driver+2,es POP ES ; LOCAL ENABLE A20 GATE mov ah,05h call xms_Driver cmp ax,1 Jz A20_Controlled ; OK to go protecded mode mov dx,offset xms_mesgA20_err jmp Exit_Error ;-- Waiting procedures for enabling the A20 directly -- Wait_until_status_bit0_is_1 proc st0_clear: xor cx,cx in al,64h test al,1 jnz st0_set loop st0_clear jmp A20_8042_timeout st0_set: ret endp wait_until_status_bit1_is_0 proc st1set: xor cx,cx in al,64h test al,2 jz st1_clear loop st1set jmp A20_8042_timeout st1_clear: ret endp ;----- jumps here if a time out error in enableing the A20 line --- A20_8042_timeout: mov dx,offset mesg_TimeOut8042 jmp Exit_Error No_XMS: ;------- Jumps here if no XMS driver is installed --------------- ;--- Must enable A20 directly through the 8042 ( keyboard controller)---- ; It does this by setting bit 1 of the 8042's output port wich is ; inaccessable to the CPU Bus. cli call wait_until_status_bit1_is_0 mov al,0adh ;send disable keyboard command out 64h,al ; viar 8042 call wait_until_status_bit1_is_0 mov al,0d0h ;Send read 8042 output port cmd out 64h,al call wait_until_status_bit0_is_1 in al,60h ; read the output port and save it push ax call wait_until_status_bit1_is_0 mov al,0d1h ; write output port cmd out 64h,al call wait_until_status_bit1_is_0 pop ax ; write data to the output port or al,2 ; and al,not 2 out 60h,al ; seting bit 1 > enables A20 call wait_until_status_bit1_is_0 mov al,0aeh ;enable keyboard again out 64h,al call wait_until_status_bit1_is_0 ; wait a bit more ; Don't really know if need to wait so many times ;----- check if A20 really is enabled ------------- mov ax,0FFFFh mov es,ax mov ax,0 mov gs,ax mov bl,gs:[0] ;Compare location 00000000 to 100000h cmp es:[10h],bl ; Check if the same jnz A20_enabled ; if not equal then A20 *MUST* be on. not byte ptr es:[10h] ; Cange byte at adreess 100000h. mov bl,es:[10h] ; And compare again mov al,gs:[00] not byte ptr es:[10h] ; Put back value cmp al,bl ; Now see if the same jnz A20_enabled ;--- EXIT on A20 error ---- mov dx , offset mesgA20_err jmp Exit_Error ; print error mesg and exit ; --- A20 is deffently enabled --- A20_enabled: A20_Controlled: ; The A20 line should be enabled at this point ;-------------------------- A20 ACTIVE ------------------------------------ ;----------------------------------------------------------------------------- align 4 init_P_mode_Stack: ;════════════════════════════════════════════════════════════════════════ ;══════════════════ SEE IF NEED TO USE DPMI OR NOT ═════════════════════ ;════════════════════════════════════════════════════════════════════════ ; USE DPMI TO ENTER PROTECTED MODE ; Obtain the Real Mode (acually V86) to Protected Mode Switch Entry Point mov ax,1687h int 2Fh and ax,ax jnz No_DPMI ; ax = 0 if DPMI is installed mov [DPMI_entry],di ; save entry point mov [DPMI_entry+2],es mov fs:[Base_Segment],SS mov ax,DOS_CODE ;set Tempery Protected Mode stack area mov ss,ax mov sp,offset init_P_mode_Stack ; Use memory for the DPMI OS private data area mov es,fs:[Base_Segment] add fs:Base_Segment,si cmp fs:Base_Segment,09900h ; See if enough base memory mov dx,offset No_Mem_err jae Exit_Error call Allocate_Base ; Set descriptor base to here mov eax,fs:[xms_usage] mov xms_usage_tmp,eax mov gs,fs:[psp_segment] ;Save environment pointer push word ptr gs:[2Ch] ; Call the V86 To Protected Mode Switch Entry Point mov ax,1 ; use 32 DPMI ( big stack ) call dword ptr [DPMI_entry] mov dx,offset pmiERr Jc Exit_Error ;************** NOW IN DPMI PROTECTED MODE ****************** ; as a 16 bit but want 32 bit push ds ; load ES to data segment pop es cmp xms_usage_tmp,0 jz No_DPMI_MEMORY ; Get Free memory info mov ax,0500h mov edi,offset Call_data int 31h mov word ptr Call_data.c_edx,offset dpmi_free_err jc print_error mov eax,dword ptr Call_data+00h ; first get total avalible. mov ebx,dword ptr Call_data+08h ; get lockable size (pages) cmp ebx,-1 ; if 0ffffffffh then has invalid info jz _lesslck shl ebx,12 ; convert limit pages into Bytes cmp eax,ebx ; get the lowest of the two jb _lesslck mov eax,ebx _lesslck: ; Only Allocate memory defined in xms_usage cmp eax,xms_usage_tmp jbe LvDmpiSize mov eax,xms_usage_tmp LvDmpiSize: mov xms_usage_tmp,eax mov ebx,eax shr ebx,12 dec ebx mov word ptr [XMS_desc+0],bx ; Set xms descriptor Limit shr ebx,16 and bl,0fh or byte ptr [XMS_desc+6],bl ; Allocate memory Block mov cx,ax ; Olny allocate the Lockable memory shr eax,16 mov bx,ax mov ax,0501h int 31h mov word ptr Call_data.c_edx,offset dpmi_aloc_err jc print_error ; Returns BX:CX with the linear address mov word ptr [XMS_Desc+2],cx ; Set Desciptor base mov byte ptr [XMS_Desc+4],bl mov byte ptr [XMS_desc+7],bh mov _tmpL_xms_base,CX ; store base address mov _tmpH_xms_base,BX No_DPMI_MEMORY: ; Set DPL for all descriptors to CPL mov si,offset GDT+8 + 5 setDPL: or byte ptr [si],01100000b add si,8 cmp si, 11*8 +5 jbe setDPL ; Allocate 11 descriptors mov AX,0000h mov CX,11 int 31h mov word ptr Call_data.c_edx,offset erralc_mesg jc print_error mov DPMI_Selector,ax ;---- Set Descriptors ----- xor esi,esi set_Descr: mov ax,000Ch ; Set Descriptor mov bx,DPMI_Selector push bx mov edi,offset GDT +8 mov edx,esi shl edx,3 add edi,edx int 31h mov word ptr Call_data.c_edx,offset errset_mesg jc print_error mov ax,0003h ; Get Next Selector incremental value int 31h add DPMI_Selector,ax inc esi cmp esi,11 ; must set 11 descriptors jb set_Descr pop DS ; Pop all the selector values that were pushed. ASSUME DS:CODE32 MOV DATA_sel,DS POP CODE32_sel POP ENVIRONMENT_sel POP PSP_sel POP DOS_DATA_sel POP DOS_CODE_sel POP VIDEO_sel POP BASE_sel POP XMS_sel POP FLAT_CODE32_sel POP FLAT_DATA_sel mov es,[PSP_Sel] ; Restore environment pointer pop word ptr es:[02Ch] mov es,DOS_data_sel ASSUME ES:DOS_CODE mov eax,ES:xms_usage_tmp mov xms_usage,eax ; return store the acual amout allocted mov eax,dword ptr ES:_tmpL_xms_base mov xms_base,eax ; store the base address ; Get the base interrupt values of the PIC's mov ax,0400h int 31h mov ES:PIC1_base,dh mov ES:PIC2_base,dl cli mov ax,0205h mov cx,CODE32_sel ; set int vector setdmpiInts macro in mov edx,offset irq&in int 31h inc bl endm mov bl,es:PIC1_base setdmpiInts 0 x=0 rept 8 ; setdmpiInts %x x=x+1 endm mov bl,es:PIC2_base x=8 rept 8 ; setdmpiInts %x x=x+1 endm mov edx,offset DPMI_EmulateRealInterupt mov bl,20h int 31h mov es:DPMI_entry,offset Start32 mov ax,CODE32_sel mov es:DPMI_entry+2,ax ;----- Jump to 32bit mode through CODE 32 descriptor ----- jmp dword ptr es:DPMI_entry ASSUME DS:DOS_CODE print_error: push Call_data.c_edx mov Call_data.c_edx,offset all_DPMI_err call print pop Call_data.c_edx call print dpmi_exit: mov ah,4ch int 21h print proc near mov Call_data.c_eax,0900h mov Call_data.c_DS,DOS_CODE mov ax,0300h ; sim real int mov bl,21h mov bh,0 mov edi,offset call_data xor cx,cx int 31h ret endp ;================================================== ; FINISHED SETTING PROTECTED MODE FOR DPMI ;=================================================== No_DPMI: ;════════════════════════════════════════════════════════════════════════════ ; Jups here if the operating system dos not support DPMI. ; Must enter protected mode directly. ; ;════════════════════════════════════════════════════════════════════════════ ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ; See if in V86 mode Because if so we can't go any further smsw ax ; Not allowed to use, MOV EAX,CR0 test al,1 mov dx,offset _inV86_err jnz Exit_Error ; See if enough base memory for TSS, IDT that get build below. ; cmp fs:Base_Segment,09A00h ; ja no_mem cmp xms_driver,00 ; Can't use XMS sevices if got no XMS dirver. jz No_XMS_MEMORY ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ; Use the XMS services to allocate extended memoey cmp fs:xms_usage,0 ; if no memory is requested then jz Extended_mem_set ; don't bother allocating memory ; Must have XMS V3.0 to work ; mov ah,00 ; Get XMS Version number ; call XMS_Driver ; cmp ah,3 ; mov dx,offset xms_vers_err ; jnae Exit_Error ; QUERY FREE EXTENDED MEMORY MOV AH,08h call XMS_Driver ; returns eax with KB free and eax,0ffffh and al,0FCh ; want page granular shl eax,10 ; put KB -> bytes ;Only Allocate memory defined in xms_usage cmp eax,fs:xms_usage jbe LvXmsSize mov eax,fs:xms_usage LvXmsSize: mov fs:xms_usage,eax mov edx,eax shr edx,10 and dl,0FCh ; want page granular call set_xms_limit ; set limit to eax ; ALLOCATE ANY EXTENDED MEMORY BLOCK ( size in eDX ) mov ah,09h call XMS_Driver cmp ax,1 jz xms_alloc_OK mov dx,offset xms_alloc_err jmp Exit_Error xms_alloc_OK: mov XMS_handle,dx ; Save XMS block handle ; LOCK THE ALLOCATED EXTENDED MEMORY BLOCK mov ah,0ch call XMS_Driver cmp ax,1 jz XMS_locked_OK mov dx,offset xms_lock_err jmp Exit_Error XMS_locked_OK: ; DX:BX has "PHYSICAL" address. mov word ptr [XMS_Desc+2],bx ;set xms descriptor mov byte ptr [XMS_Desc+4],dl ; Base. mov byte ptr [XMS_Desc+7],dh mov word ptr fs:xms_base,BX ; set base of block mov word ptr fs:xms_base+2,DX jmp Extended_mem_set No_XMS_MEMORY: ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ; ALLOCATE EVERY SINGLE BYTE OF EXTENDED MEMORY IF NO XMS DRIVER IS INSTALLED ; GET EXTENDED MEMORY SIZE FROM CMOS RAM - mov al,24 ; get MSB out 70h,al in al,71h shl ax,8 mov al,23 ; get LSB out 70h,al in al,71h and eax,0ffffh shl eax,10 ; Kbytes -> bytes mov fs:xms_usage,eax call set_xms_limit ; set limit to eax mov fs:xms_base,100000h ;Always start block at 1MB Extended_mem_set: ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ; Extended memory is allocated at this point CLI in al,21h mov oirqMask,al in al,0a1h mov oirqMask+1,al ;-- remap IRQ int vectors --- mov bl,Pic_Base mov bh,Pic_Base+8 call set_8259intvec mov al,oirqMask out 21h,al mov al,oirqMask+1 out 0A1h,al ; THE INTERRUPT DESCRIPTOR TABLE ; Use memory for the Interrupt Descriptor Table and the TSS mov ax,fs:Base_Segment ; Set IDT Reg base mov es,ax and eax,0ffffh shl eax,4 mov dword ptr IDTR_value+2,eax mov fs:[IDT_base],eax xor eax,eax ; Clear all the new memory xor edi,edi mov ecx,(8*256 +TSS_Ends+16)/4 cld rep stosd ;--- Build the Interrupt Descriptor Table --- mov eax,InterruptGATE_a mov edx,InterruptGATE_B xor cl,cl xor si,si @MakeIDT: mov es:[si],eax ; Put into memory mov es:[si+4],edx ; Put into memory add si,8 dec cl jnz @MakeIDT ;---- Set interrupt vector 31h ------ mov word ptr es:[31h*8],offset MyDPMI_services ;---- Set interrupt vector 21h ------ mov word ptr es:[21h*8],offset Go_REAL_MODE mov word ptr es:[21h*8+2], Dos_Code_desc - GDT ; ---- Set the 16 hardware and 16 exception interrupt handlers -------- setexecp macro n mov word ptr es:[n*8],offset _386exception_&n mov word ptr es:[(Pic_Base+n)*8],offset firstIRQ&n endm x=0 rept 16 setexecp %x x=x+1 endm ; ---- Set general protection exception handler interrupt -------- mov word ptr es:[13*8],offset General_Exeption_Handler ; ---- Set real mode interrupt emulation handler interrupt -------- mov word ptr es:[20h*8],offset My_EmulateRealInterupt ;-- Build the Task State Segment -- add fs:Base_Segment,80h mov es,fs:Base_Segment xor eax,eax ; Get TSS base address mov ax,es shl eax,4 mov fs:tss_Level0ESP,eax ;Save address of level0 ESP TSS field add fs:tss_Level0ESP,offset tss_esp0 ;Need to use it latter mov MyMain_TSS_Desc+2,ax ; Load Base address of TSS descriptor shr eax,16 mov byte ptr MyMain_TSS_Desc+4,al ;Load important TSS fields ; ; NOTE: The level0 stack field is set when real mode interrupt emulation ; is called mov es:tss_iobase, 068h mov es:tss_ioend,11111111b ; TSS is now built . Time to set the base descriptor base address just ; after the TSS and IDT are located. add fs:Base_Segment,(TSS_Ends+15)/16 ;add to Base_Segment call Allocate_Base CLI ; Can't have interrupts anymore ; Load the Interrupt descriptor table register lidt qword ptr IDTR_value ; Load the Global descriptor table register mov EAX,DOS_CODE shl EAX,4 add dword ptr GDTR_value+2 , EAX lgdt qword ptr GDTR_value ; Enter Protected Mode mov eax,CR0 or al,1 ; Set PE bit of CR0 mov CR0,eax db 0EAh ; Jump to 32bit mode through CODE 32 descr dw offset Setup_Pmode , CODE32_Desc - GDT ;-------------------------------------------------------------------------- ; END OF PROTECTED MODE INITALIZATION ;-------------------------------------------------------------------------- ;---------------------------------------------------------------------------- ;───────────────────── INTERNAL ROUTINES ─────────────────────────────────── ;---------------------------------------------------------------------------- assume ds:dos_code ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· set_xms_limit proc ; Set the xms descriptor limit. shr eax,12 dec eax mov word ptr [XMS_Desc+0],ax ; set limit [0..15] shr eax,16 or byte ptr [XMS_desc+6],al ; limit [16..19] ret endp ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· Allocate_Base proc mov ax,fs:Base_Segment ; Set BASE data descriptor to this and eax,0ffffh shl eax,4 mov word ptr [Base_Desc +2 ],ax shr eax,16 mov byte ptr [Base_Desc +4 ],al ret ENDP ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· dosstart endp DOS_CODE ENDS CODE32 SEGMENT PARA PUBLIC USE32 assume DS:CODE32 , CS:CODE32 , ES:CODE32 ; Flat memory model segment align 4 CODE32_sel dw CODE32_desc - gdt public CODE32_sel DATA_sel dw data_desc - gdt public DATA_sel VIDEO_sel dw video_desc - gdt public VIDEO_sel FLAT_DATA_sel dw FLAT_DATA_desc - gdt public FLAT_DATA_sel FLAT_CODE32_sel dw FLAT_CODE32_desc - gdt public FLAT_CODE32_sel XMS_sel dw XMS_desc - gdt public XMS_sel BASE_sel dw BASE_desc - gdt public BASE_sel PSP_sel dw PSP_desc - gdt public PSP_sel ENVIRONMENT_sel dw ENVIRONMENT_desc - gdt public ENVIRONMENT_sel align 4 Real_GS dd 0 public Real_GS Real_FS dd 0 public Real_FS Real_DS dd 0 public Real_DS Real_ES dd 0 public Real_ES Real_SS dd V86_Stack ; Setup initial V86 stack public Real_SS Real_SP dd V86_stack_size public Real_SP global xms_usage :dword global xms_base :dword global Base_Segment :word global PSP_segment :word global START32 :near global IRQ0 :near global IRQ1 :near global IRQ2 :near global IRQ3 :near global IRQ4 :near global IRQ5 :near global IRQ6 :near global IRQ7 :near global IRQ8 :near global IRQ9 :near global IRQ10 :near global IRQ11 :near global IRQ12 :near global IRQ13 :near global IRQ14 :near global IRQ15 :near align 4 tss_Level0ESP dd 0 V86_Lv0_ESPSave dd 10h dup (0) ; TSS level 0 ESP save for V86 calls. V86_Lv0_SSSave dw 10h dup (0) ; TSS level 0 SS save for V86 calls. IDT_base dd 0 _tmp0_ dd 0 _tmp1_ dd 0 _tmp2_ dd 0 tmp_Real_Flags dw 0 V86_irq_Count db 0 DOS_CODE_sel dw DOS_CODE_Desc - GDT DOS_DATA_sel dw DOS_DATA_Desc - GDT ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· Setup_Pmode: ; first 32bit protected mode point ;!! MUST LOAD SEGMENT REGISTERS VALID SELECTORS !! mov ax,cs:[Data_SEL] mov es,ax mov fs,ax mov gs,ax mov ds,ax mov ax,MyMain_TSS_Desc - GDT ; Set TR to any valid TSS ltr ax mov ss,[flat_data_sel] ; Setup initial Protected mode stack mov esp,seg init_P_mode_Stack shl esp,4 add esp,offset init_P_mode_Stack db 0eah ; jump to start of main program dd offset start32 , CODE32_desc - gdt ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;************** EXCEPTION HANDLERS ... ********************* Exception: mov ax,DATA_desc - gdt mov ds,ax mov es,Flat_data_sel mov ss,DATA_sel mov fs,FLAT_data_sel mov gs,FLAT_data_sel mov esp,100h mov dx,offset unknown_int_exit_mesg mov ebp,'ERRA' ; Exit with error code int 21h getexeec macro n _386exception_&n&: mov dx,offset e_&n jmp All_exceptions endm x=0 rept 16 getexeec %x x=x+1 endm ;═══════════════════════════════════════════════════════════════════════════ All_exceptions: ; jmp _Pmode_exit_error ;∙·∙·∙·∙·∙·∙·∙·∙∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· _Pmode_exit_error: cli mov ss,CS:[DATA_SEL] ; set up some stack to exit mov esp,offset CODE32_end_of + 100h mov ebp,'ERRA' int 21h ; Exit with error set1STirqm macro nt local not_v86_irq_ firstIRQ&nt: push offset irq&nt jmp check_HardwareINT endm x = 0 rept 16 set1STirqm %x x=x+1 endm ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;═══════════════════════════════════════════════════════════════════════════ check_HardwareINT proc near test dword ptr [esp+3*4],020000h jz not_v86_irq ; jump if IRQ was from P.mode push eax ; IRQ was from V86 mode. mov ds,cs:DATA_sel mov eax,[esp+5*4] ; Put new V86 stack pointer mov [Real_SP],eax mov eax,[esp+6*4] ; Put new V86 stack segment mov [real_SS],eax ; we Don't care about ES,DS,FS & GS pop eax mov fs,[esp+10*4] ; return segment reg selectors mov ds,[esp+11*4] ; as they were before entering V86 mov gs,[esp+12*4] mov es,[esp+13*4] not_v86_irq: ret ; Go to IRQ handler endp ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;═══════════════════════════════════════════════════════════════════════════ ;------- The General Exception Handler ( Int 13 ) --------------- ;═══════════════════════════════════════════════════════════════════════════ General_Exeption_Handler: test dword ptr [esp+4*3],0020000h ; Test VM bit jnz V86_Monitor mov dx,offset e_13 ; if exception from p.mode then terminate. jmp All_Exceptions ;***************************************** ;********* Virtual 8086 exception handler ********* ;***************************************** V86_Monitor proc add esp,4 ; delete the undocumented pushed error code ?? pushad mov fs,CS:Flat_DATA_SEL ;;; Find what instruction caused the exception ;;;; movzx ebx,word ptr [esp+36] ; Get CS from stack shl ebx,4 add ebx,[esp+32] ; Get EIP form stack inc dword ptr [esp+32] mov dl,fs:[ebx] ; Get opcode mov al,3 cmp dl,0cch ; see if INT 3 Breakpoint je short DO_v86int ; if so do it's int mov al,4 cmp dl,0ceh ; See if INTO je short Do_v86int ; if so do it's int cmp dl,0cdh ; see if INT n jne V86exc ; if not then exception inc dword ptr [esp+32] ; It must be a INT n instruction mov al,fs:[ebx+1] ; get INT n number cmp al,0FFh ; If int 0ffh and Then jz Exit_V86 ; return to main Program cmp al,15h jnz NoXmsToCopy cmp byte ptr ss:[esp+7*4+1],87h ; Detect if v86 application jz Emulate_XMS_COPY ; wants to copy extended mem ; i.e ah = 87h NoXmsToCopy: public DO_v86int ;****; Emulate V86 interrupt ;****; DO_v86int: ; Do interrupt "AL" for V86 task movzx ebx,al shl ebx,2 ; Get 8086 Int Vector movzx edx,word ptr [esp+(8+4)*4] ; Get SS stored on stack shl edx,4 sub word ptr [esp+(8+3)*4],6 ; Sub ESP stored on stack by 6 add edx,[esp+(8+3)*4] ; edx = Phyical Address of V86 stack mov ax,[esp+(8+2)*4] ;Put FLAGS from Prev.0 Stack to V86 stack mov fs:[edx+4],ax mov ax,[esp+(8+1)*4] ;Put CS from Prev.0 Stack to V86 stack mov fs:[edx+2],ax mov ax,[esp+(8+0)*4] ;Put IP from Prev.0 Stack to V86 stack mov fs:[edx],ax mov eax,fs:[ebx] ; Get real mode int vector (CS:IP) mov [esp+(8+0)*4],ax ; Store it on prev. 0 Stack shr eax,16 mov [esp+(8+1)*4],ax ret86: and word ptr [esp+(8+2)*4],0fcffh ; Clear DF & IF flags on prev. 0 Stack popad iretd ; Return to V86 mode ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ; Stop emulating V86 mode interrupts and return to main program. ; Jumps here when v86 code causes an exception from the Int 0FFh instuction Exit_V86: mov DS,CS:DATA_SEL ; Need to use data segment popad mov [_tmp0_],eax mov [_tmp1_],ebx mov [_tmp2_],ecx ; Pop off all the stuff pushed from V86 exception. add esp,8 ; ignore EIP & CS pop eax ; Get Efplags and eax,NOT 23000h ; Clear VM bit mov [esp+13*4],eax ; Put onto stack pop [Real_SP] pop [Real_SS] pop [Real_ES] pop [Real_DS] pop [Real_FS] pop [Real_GS] ;Must return the TSS Level 0 ESP to the previous V86 call's Level 0 ESP value. dec V86_irq_Count movzx eax,V86_irq_Count sub al,1 jl jH98_V86 ; Only do it if a V86 call inside a call. mov bx,[V86_Lv0_SSSave +EAX*2] ; Get previous TSS Lv0 SS mov eax,[V86_Lv0_ESPSave+EAX*4] ; Get previous TSS Lv0 ESP mov ecx,[tss_Level0ESP] ; Get address of TSS Lv0 ESP mov fs:[ecx],eax ; Load ESP. mov fs:[ecx+4],bx ; Load SS. jH98_V86: mov eax,[_tmp0_] ;Return temperaly saved registers mov ebx,[_tmp1_] mov ecx,[_tmp2_] pop fs ds ; pop seg reg from the entering V86 pop gs es ; call; see My_EmulateRealInterupt proc iretd ; Return to main program and continue. ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;═══════════════════════════════════════════════════════════════════════════ ; Emulate the SYSTEM BIOS - COPY EXTENDED MEMORY Srevice for V86 application ; INT 15 & AH = 87h ;═══════════════════════════════════════════════════════════════════════════ Emulate_XMS_COPY: ; A20 gate always seems to be on ? mov ecx,[esp+(6)*4] ; Get Number of words to copy and ecx,0ffffh cmp cx,8000h ja _error_1587 shr ecx,1 ; CALCULATE THE LOCATION OF THE GDT. xor eax,eax mov ax,[esp+(8+5)*4] ; Get ES shl eax,4 movzx ebx,word ptr [esp+(1)*4] ; Get SI add eax,ebx ;EAX has location of GDT mov esi,fs:[eax+7h+10h] shl esi,24 mov edx,fs:[eax+2h+10h] ; Get 32bit Source address and edx,0ffffffh add esi,edx mov edi,fs:[eax+7h+18h] shl edi,24 mov edx,fs:[eax+2h+18h] ; Get 32bit Destination address and edx,0ffffffh add edi,edx push fs pop es cld rep movs dword ptr es:[edi],es:[esi] ; do the transfer mov byte ptr [esp+(7*4)+1],00 ;return AH = 0 and byte ptr [esp+(8+2)*4],NOT 01 ; Clear Carry flag on prev. 0 Stack jmp ret86 _error_1587: or byte ptr [esp+(8+2)*4],01 ; Set Carry flag on prev. 0 Stack mov byte ptr [esp+(7*4)+1],03 ;return AH jmp ret86 ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;═══════════════════════════════════════════════════════════════════════════ V86exc: mov dx,offset _V86_illigal_err jmp _Pmode_exit_error ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· ;¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ endp ;********************************** MyDPMI_services:;********************* ;********************************** cmp ax,0205h jz SetPmodeintVector cmp ax,0204h jz GetPmodeintVector cmp ax,0400h jz GetVersion iretd SetPmodeintVector: push edi ebx fs ds mov ax,data_desc - gdt mov ds,ax mov fs,[flat_DATA_sel] movzx ebx,bl mov edi,ebx sub edi,Pic_Base ; No allowed to set the hardware int vectors cmp edi,15 jbe Set_irq_vec mov edi,[idt_base] mov fs:[ebx*8+edi],dx ; offset 0..15 SHR EDX,16 mov fs:[ebx*8+edi+6],dx ; offset 16..32 mov fs:[ebx*8+edi+2],cx ; Code Selector pop ds fs ebx edi iretd GetPmodeintVector: push edi ebx fs ds mov ax,data_desc - gdt mov ds,ax mov fs,[flat_DATA_sel] movzx ebx,bl shl ebx,3 add ebx,[idt_base] mov edi,[idt_base] mov dx,fs:[ebx+6] ; Get offset 16..32 SHL EDX,16 mov dx,fs:[ebx] ; Get offset 0..15 mov cx,fs:[ebx+2] ; Get Code Selector ivec22: pop ds fs ebx edi iretd Set_irq_vec: stc jmp ivec22 GetVersion: ; Emulate DPMI service Get Version ; only need to emulate the returned values of PIC bases mov dh,PIC_base mov dl,PIC_base+8 iretd ;═══════════════════════════════════════════════════════════════════════════ ; PROCEDURES TO EMULATE REAL MODE INTERRUPT ; FOR BOTH DPMI AND MY VERSIONS ;═══════════════════════════════════════════════════════════════════════════ DPMI_EmulateRealInterupt proc far push ES DS ; save used seg registers mov DS, CS:[data_sel] ; Load DS data seg regs. push ax ; Push a 2 bytes to keep stack dword aligned for speed. push 0 ; Push the real mode SS:SP. If zero, DPMI set it up. push 0 ; ignore CS:IP not used by DPMI push word ptr [Real_GS] push word ptr [Real_FS] push word ptr [Real_DS] push word ptr [Real_ES] push word ptr [esp+4*6+2] ; get the flag register from INT 20h pushad mov edi,esp push ss pop es mov ax,0300h mov bl,[esp+4*18] ; get the V86 int number that was pushed xor ecx,ecx xor bh,bh int 31h ; Use the DPMI service popad pop word ptr [esp+14+6*4] ; return eflags pop word ptr [Real_ES] pop word ptr [Real_DS] pop word ptr [Real_FS] pop word ptr [Real_GS] add esp,10 ; Ignore CS:IP ,SS:SP and 2 bytes. pop DS ES ; Restore used seg registers. iretd ; Return from INT 20h ENDP ;∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙·∙· My_EmulateRealInterupt proc far push es gs ds fs ; save segment registers. mov ds,cs:[data_sel] ; Load seg regs. mov fs,[flat_data_sel] mov _tmp0_,eax ; temperly save eax. mov eax,[esp+4*6] ; Get flags from stack. mov [tmp_Real_Flags],ax ; Temperaly saved them. mov eax,[tss_Level0esp] ; Set Level 0 stack to current SS:ESP mov fs:[eax],esp mov fs:[eax+4],SS movzx eax,V86_irq_Count ; Save the TSS LV0 Stack mov [V86_Lv0_ESPSave+EAX*4], ESP mov [V86_Lv0_SSSave+EAX*2], SS inc V86_irq_Count pushfd ; Clear Nested Task, ( bit 14 ) pop eax ; If set then the 386 will and ah,10111101b ; use the back link field in the TSS push eax ; to switch tasks. A no no. popfd mov al,[esp+4*7] ; Get the V86 interrupt number mov byte ptr [ V86Int_instuction+1],AL ; put it push [Real_GS] ; GS push [Real_FS] ; FS push [Real_DS] ; DS push [Real_ES] ; ES push [Real_SS] ; SS push [Real_SP] ; ESP mov eax,00023000h ; IOPL = 3 , VM = 1 or ax,[tmp_Real_Flags] push eax ; EFLAGS mov eax,seg TASK0_V86 push eax ; CS mov eax,offset TASK0_V86 push eax ; EIP mov eax,_tmp0_ ; Return origonal EAX value IRETD ; Enter V86 mode !!!!! endp ;¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡¡ TASK0_V86: V86Int_instuction: int 000h int 0ffh ; Tell V86 exception handler to exit. CODE32_end_of: CODE32 ENDS V86_STACK SEGMENT public stack 'stack' USE16 db V86_stack_size dup (?) V86_STACK ENDS END DosStart