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Assembly Source File | 1994-09-05 | 50.3 KB | 1,571 lines

; >>> this is file LOADLIN.ASM ;============================================================================ ; LOADLIN v1.5 (C) 1994 Hans Lermen (lermen@elserv.ffm.fgan.de) ; ; This program is free software; you can redistribute it and/or modify ; it under the terms of the GNU General Public License as published by ; the Free Software Foundation; either version 2 of the License, or ; (at your option) any later version. ; ; This program is distributed in the hope that it will be useful, ; but WITHOUT ANY WARRANTY; without even the implied warranty of ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ; GNU General Public License for more details. ; ; You should have received a copy of the GNU General Public License ; along with this program; if not, write to the Free Software ; Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. ; ;---------------------------------------------------------------------------- ; Comments and bug reports are welcome and may be sent to: ; E-Mail: lermen@elserv.ffm.fgan.de ; SnailMail: Hans Lermen ; Am Muehlenweg 38 ; D53424 REMAGEN-Unkelbach ; GERMANY ; ;============================================================================ ; ; NOTE: ; ; This program could not have been written as quickly without ; the information found in the source code of F.Coutant's BOOTLIN ; ; This program contains some modified source code from ; my protected mode extender (LDOSX (C) 1991..1994 H.Lermen), ; which was written as a fast multitasking alternative ; to DJ.Delorie's extender (it runs DJ-GCC compiled binaries under DOS). ; ; I was too lazy to reprogram the subroutines completely, so, ; if You wonder what nonsense they are doing, keep in mind that they ; were written for an other purpose. ; ;============================================================================ ; ; Contributions and bug fixes for 1.5: ; ; ; Javier Achirica <javier@autom.uva.es> ; ; invented the switch-out-of-setup method (Javier's method), ; which makes the BIOSINTV and REALBIOS method superfluous on nearly ; all machines. The trick is: let setup run in V86 and intercept ; just before going to protected mode. ; (Thank you Javier for this very good work). ; ;============================================================================ name load_linux .386 locals jumps REALBIOS_FILE equ 'C:\REALBIOS.INT' SIGNATURE = 'SrdH' ; "HdrS" space4k = 1000h space2k = 800h space1k = 400h our_stacksize = space2k kernel_start_ equ 01000h ; here the kernel must go kernel_end equ 09000h standard_setup_sects equ 4 ; number of setup sectors, older kernels maximum_setup_sects equ (32-1) ; max number of setup sectors for newer kernels High_Seg equ kernel_end ; here first 512 + 4*512 + n*512 bytes of image must go High_Addr equ (High_Seg*16) setup_intercept_int equ 7fh debug_stop macro marker mov ax,0b800h mov ds,ax mov byte ptr ds:[1],70h mov byte ptr ds:[0],marker jmp short $ endm align_ macro start,val org (((($-start)+(val-1))/val)*val) endm psp_seg segment at 0 use16 ; -------------PSP Program Segment Prefix---------------------- org 2h PSP_memend_frame dw ? org 2ch PSP_envir_frame dw ? org 80h PSP_DTA db ? (100h-80h) dup(?) ; ------------------------------------------------------------- psp_seg ends code segment para use16 assume cs:code,ds:psp_seg,es:code code_org0 label byte ; --------------------------------------------------------------------- ; Bootsector (512 bytes) ; within this BEFORE start of setup: ; (may be set by "LOADLIN") bootsec label byte org 20h CL_MAGIC dw ? ;0020 commandline magic number (=0xA33F) CL_OFFSET dw ? ;0022 commandline offset ; Address of commandline is calculated: ; 0x90000 + contents of CL_OFFSET ; The command line is parsed by "init/main.c" ; Value of NAME=XXXX are put into the environement ; and can then be interpreted by the drivers ; and /etc/rc. The variabel "root=xxxx" is ; interpreted by main directly, "single" is ; interpreted by init or simpleinit. org 1F1h setup_sects db ? ; no. of sectors ro_flag dw ? ; =0: root file system should be mounted read-write ;<>0: root file system should be mounted readonly ; (this will be overwritten by the kernel commandline ; options "ro" / "rw") ; -------------------------------- ; within this AFTER setup has run: org 0 curr_curs dw ? ;0000 saved cursor position ext_mem_size dw ? ;0002 extended memory size in Kb (from int 0x15) org 80h hd0_disk_par label byte ;080 hd0-disk-parameter from intvector 0x41 hd1_disk_par label byte ;090 hd1-disk-parameter from intvector 0x46 ; -------------------------------- ; within this as loaded from "zImage" org 01F4h kernel_size dw ? ; size of kernel-part in the image-file ; (in 16 byte units, rounded up) swap_dev dw ? ; swap device ram_disk dw ? ;01F8 size of ram-disk (in 1Kb units ) or ZERO ; if ram_disk is nonZERO then the kernel ; (driver/block/ramdisk.c: rd_load() ) ; will try to load the contents for the ram-disk ; from the "root_dev" which MUST then have the ; floppyMAJOR. ; The file-system on that floppy must be MINIX ; If rd_load() succeeds it sets the root_dev ; to the ramdisk for mounting it. ; ; LOADLIN parses the commandline for the string ; "ramdisk=nnn" where nnn is the value for "ram_disk" ; after the kernel images has been loaded by LOADLIN ; it asks for inserting the floppy. ; (NOTE: You may have LOADLIN in A: and root_dev in B: ; or vice versa). vga_mode dw ? ;01FA VGA-Mode ; -3 = ask ; -2 = Extended VGA ; -1 = Normal VGA ; 0 = as "0" was pressed ; n = as "n" was pressed ; ; LOADLIN parses the commandline for the string ; "vga=nnn" where nnn is the value for "vga_mode" ; it also excepts: ; "vga=ask","vga=normal",'vga=extended" root_dev dw ? ;01FC Root Device (high=Major, low=minor) ;(this can be overwritten by the kernel commandline ; option "root=XXXX") bootmagic dw ? ;01FE Bootsector magic (0AA55h) ; ------------------------------------------------------------------- ; this area will be used to pass params ; from LOADLINX to LOADLIN, if the params file name is @@loadlinx@@ switch ; ; NOTE: @@loadlinx@@ must NOT be used, ; if starting LOADLIN without LOADLINX org 0200h params_from_loadlinX label byte ; ------------------------------------------------------------------- org 0200h setup_prog label byte ; the setup-program itself ; must be started at 9020h:0 !!! ; ======= jmp short start_of_setup ; the setup header ; (if you have applied the setup.S patch, ; or later, if we have it in the standard kernel) setup_header_sign dd ? setup_header_version dw ? setup_realmode_switch dd ? start_sys_seg dw ? kernel_version dw ? ; end of header start_of_setup: org setup_prog db maximum_setup_sects*512 dup(?) ; ------------------------------------------------------------- ; the following layout is private tp LOADLIN.EXE : align_ code_org0,4096 pagedir dd 2 dup(0) ; must be aligned to 4 K ; NOTE: we have only 1 (one) pagetable, so we ; need only 1 pagedir entry ; All current known CPUs (386,486,PENTIUM) ; tolerate the garbage behind this, ; as long as there is no access > 4MB. ; So we may overlap the pagedir with ; our code PSP_frame dw 0 ; our psp fhandle dw 0 ; file handle of imagefile kernel_start dw 0 ; place were the kernel must at time of ; start of setup free_mem_start dw 0 ; frame of free memory, starting at the begin of LOADLIN.EXE kernel_load_frame dw 0 ; where to load the image ; ----------------------------v ; the following values are cleared on each call to "parscommandline" ; (see "clear_to_default") parse_switches label byte new_setup_size dw 0 new_vga_mode dw 0 new_ram_disk dw 0 new_root_dev dw 0 new_ro_flag dw 0 cl_pointer dw 0 ; while parsing: aux pointer to command_line got_vga_mode db 0 got_ram_disk db 0 got_root_dev db 0 got_ro_flag db 0 option_v db 0 option_t db 0 option_t_forced db 0 option_realbios db 0 option_rx db 0 option_ja db 0 option_clone db 0 option_oldxd db 0 option_n db 0 option_nodiskprompt db 0 intv_size dw 0 wrong_realbios db 0 have_to_force_realmode db 0 ; 0 = is in realmode ; 1 = is in V86, have to reenter realmode before ; kernel goes to protected mode ; have_to_intercept_setup db 0; 0 = old method, no interception ; 1 = intercept boot/setup.S (Javier's method) ; of older kernels just before going to ; protected mode. ; 2 = same as 1, but intercepting newer kernels ; with the setup.dif patch applied. ; debug_file_handle dw 0 ; set to file handle if option -d is set logo_out db 0 kernelversion dd 0 ; binary kernel version, decoded from ; the version string as follows: ; "1.2.3 (root@...) #4" becomes 01020304h ; if string is only 1.2.3 ---> #0 is assumed parse_switches_end label byte ; ----------------------------^ can_exit_to_dos db 0 cannot_load_because_of_windows db 0 print_dots db 0 cpu_check_status dw 0 ;NOTE: all uninitialized data has been moved to end of modul ; since version 1.4 ; ------------------------------------------------------------- _DEALLOCATE_PAGES = 45h; _GET_VERSION = 46h; _ALLOCATE_RAW_PAGES = 5A01H EMM_int = 67h; descript struc limit dw ? base0 dw ? base16 db ? typbyte db ? limit16 db ? base24 db ? descript ends Gdescript struc gateoffs0 dw ? gateselector dw ? gatenotused db ? gatetyppbyte db ? gateoffs16 dw ? Gdescript ends ; definition of COMMON decriptor types (bit0..4 of descript.typbyte ) ; (bit 4 of descript.typbyte =0) data_d = 10000b ; data segment descriptor writable = 00010b ; =1 if write acces allowed to data segment expand_down = 00100b ; =1 limit counts down from base code_d = 11000b ; code segment readable = 00010b ; =1 if code also can be read (cannot be ovwritten) conforming = 00100b ; =1 code can be accesses and executed ; regardless of it's privilege level ; definition of SYSTEM decriptor types (bit0..4 of descript.typbyte ) ; (bit 4 of descript.typbyte =0) TSS286_avail_d = 01h LDT_d = 02h TSS286_busy_d = 03h call_gate_d = 04h task_gate_d = 05h INT286_gate_d = 06h TRAP286_gate_d = 07h TSS386_avail_d = 09h TSS386_busy_d = 0bh call386_gate_d = 0ch INT386_gate_d = 0eh TRAP386_gate_d = 0fh ; definition of privilege levels (bit5..6 of descript.typbyte ) p0 = 0 ;┐ p1 = 1*32 ;├ super visor levels p2 = 2*32 ;┘ puser = 3*32 ;definition of granularity ( bits7..8 in descript.limit16 ) gran_byte = 0 gran_page = 10000000b ; 4k granularity ; for data_selectors: data_USE16 = 0 gran_big = 01000000b ; big segment data_USE32 = gran_big ; use 32-bit stack pointer ESP instead of SP ; Intel says: relevant only together with expand_down for data_d ; But that is WRONG : ; BIG segment must be set also if the descriptor is greater 64K ; and is used to load SS ! ; (because SP cannot access behind 64K) ; ; for code_selectors: code_USE32 = 01000000b ; default operand size 32 bit (for code segments) code_USE16 = 00000000b ; default operand size 16 bit (for code segments) ; segment present bit (bit7 of descript.typbyte ) is_present =128 not_present =0 descriptor macro name,typ,plevel,present,limit,gran,base name descript <limit and 0ffffh,base and 0ffffh,low (base shr 16),typ or plevel or present,(limit shr 16) or gran,high (base shr 16)> endm ;GDT Global Descriptor Table -------------------------v align_ code_org0,16 gdtnull descript <?> ;0000 never accessable gdtvcpi_code descript <?> ;0008 gdtvcpi2 descript <?> ;0010 gdtvcpi3 descript <?> ;0018 descriptor gdt_core,(data_d+writable),p0,is_present,0fffffh,(gran_page+data_USE32),0 descriptor gdt_code,(code_d+readable),p0,is_present,0ffffh,(gran_byte+code_USE16),High_Addr descriptor gdt_data,(data_d+writable),p0,is_present,0ffffh,(gran_byte+data_USE16),High_Addr descriptor gdt_ldt,LDT_d,p0,is_present,7,gran_byte,(High_Addr+(ldtnull-code_org0)) descriptor gdt_tss,TSS286_avail_d,p0,is_present,0ffh,gran_byte,(High_Addr+(our_tss-code_org0)) gdtlast descript <?> ; dummy for addressing g_vcpi_code equ (gdtvcpi_code-gdtnull) g_core equ (gdt_core-gdtnull) g_code equ (gdt_code-gdtnull) g_data equ (gdt_data-gdtnull) g_ldt equ (gdt_ldt-gdtnull) g_tss equ (gdt_tss-gdtnull) ;GDT Global Descriptor Table -------------------------^ ;LDT Local Descriptor Table -------------------------v ldtnull descript <?> ;0000 never accessable ldtlast descript <?> ; dummy for addressing ;LDT Local Descriptor Table -------------------------^ ; align_ SYSTEMDATA_,1024 ;IDT Interrupt Descriptor Table -------------------------v idtnull descript 32 dup (<0>) idtlast descript <?> ; dummy for addressing ;IDT Interrupt Descriptor Table -------------------------^ our_tss dd 128 dup (?) ; our TSS Task State Segment ;params for switching TO protected mode -------------------------v ;NOTE: this Data MUST be in LOW_MEM (below 1 Mbyte), ; data referenced by this structure ; CAN be in memory above 1 Mbyte ; On switching to protected mode the server ; first loads CR3 (paging base) from "our_CR3". ; ; value of CR3 to be loaded by server our_CR3 dd (High_Addr+(pagedir-code_org0)) ; linear address in first Mbyte pointing to ; value of GDTR ("our_GDTR") to be loaded by server our_GDTRptr dd (High_Addr+(our_GDTR-code_org0)) ; linear address in first Mbyte pointing to ; value of IDTR ("our_IDTR") to be loaded by server our_IDTRptr dd (High_Addr+(our_IDTR-code_org0)) ; value of LDTR to be loaded by server our_LDTR dw g_ldt ; value of TR to be loaded by server our_TR dw g_tss ; Fword, pointer to code to be started by server protected_mode_target DD ? DW g_code ; belongs to above our_GDTR dw (gdtlast-gdtnull)-1 ;limit (byte gran) ;linear (not physical) base address of "gdtnull" laddr_GDT dd (High_Addr+(gdtnull-code_org0)) dw ? ; (just for align "laddr_IDT" to Dword) our_IDTR dw (idtlast-idtnull)-1 ;limit (byte gran) ;linear (not physical) base address of "Idtnull" laddr_IDT dd (High_Addr+(idtnull-code_org0)) ;-------------------------------------------------------------------^ pagedir_template dd (High_Addr+(page0-code_org0)+3) ; ------------------------------------------------------------- ;============================================================================= DOS_WRITE_STRING = 009h ; Display a '$' terminated string DOS_BUFFERED_INPUT = 00Ah ; Read text and store it in a buffer DOS_OPEN_FILE = 03Dh ; Open an existing file DOS_CREATE_FILE = 03Ch ; create a new file DOS_CLOSE_FILE = 03Eh ; Close a file DOS_READ_FROM_HANDLE = 03Fh ; Read from DOS file handle DOS_WRITE_TO_HANDLE = 040h ; write to DOS file handle DOS_TERMINATE_EXE = 04Ch ; Terminate program DosCall macro function_code mov ah,function_code int 21h endm DosInt macro int 21h endm push_ macro r1,r2,r3,r4,r5,r6,r7,r8,rx irp parm,<&r1,&r2,&r3,&r4,&r5,&r6,&r7,&r8,&rx> ifndef parm exitm endif push parm endm endm pop_ macro r1,r2,r3,r4,r5,r6,r7,r8 irp parm,<&r8,&r7,&r6,&r5,&r4,&r3,&r2,&r1> ifdef parm pop parm endif endm endm pushAD_struc macro prefix irp parm,<edi,esi,ebp,esp,ebx,edx,ecx,eax> prefix&&parm dd ? endm endm cpu_86 equ 0 cpu_286 equ 2 cpu_386V86 equ 3 ; is >=386, but in virtual 86 mode cpu_386GE equ 4 ; >=386 cpu_386GE_real_paging equ 5 cpu_type dw 0 cpu_check proc near pushf xor ax,ax ;0000 to ax push ax popf ; try to put that in flags pushf pop ax ; look at what really went into flags and ah,0f0h ; mask off high flag bits cmp ah,0f0h je is_8086 mov ax,0f000h push ax ; try to set the high bits popf pushf pop ax ; look at actual flags and ah,0f0h je is_80286 ; is x86, x >= 3 ; check for V86 or real-paging -mode mov ah,040h ; try to clear IOPL push ax popf pushf pop ax and ah,030h jne is_v86 cmp option_clone,0 jnz @@clone .386p mov eax,cr0 ; normally this would cause a GP(0)-exception ; (i386 Programmers Reference Guide, INTEL 1987) ; if in V86-mode, but most EMMXXXX drivers ; seem to intercept this exception and allow ; reading the CR0. .386 or eax,eax jz is_v86 ; not a valid CR0, reserved bits are allways set ; (this may be not true on a 486 clone such as ; the 486DLC, so if you have trouble with ; interpreting real mode as V86 use the -clone switch ; test al,01h ; test PE -bit jz is_greater_equal_80386 is_v86: mov ax,cpu_386V86 cpu_check_exit: mov cpu_type,ax popf ret is_8086: mov ax,cpu_86 jmp cpu_check_exit is_80286: mov ax,cpu_286 jmp cpu_check_exit is_greater_equal_80386: test eax,eax ; test PG - bit js is_386_real_pageing mov ax,cpu_386GE jmp cpu_check_exit is_386_real_pageing: mov ax,cpu_386GE_real_paging jmp cpu_check_exit @@clone: ; on some 486 clones we have problems with CR0, ; so we are looking for EMM, and then ; we assume to be in V86, if we have EMM. push ds xor ax,ax mov ds,ax mov ds,word ptr ds:[emm_int*4+2] mov ax,cpu_386V86 cmp dword ptr ds:[10+4],'0XXX' jne @@cl1 cmp dword ptr ds:[10],'QMME' je @@clex cmp dword ptr ds:[10],'XMME' je @@clex @@cl1: mov ax,cpu_386GE @@clex: pop ds jmp cpu_check_exit cpu_check endp ;============================================================================= start: .8086 ; we are not sure here if on a 368 CPU mov cs:PSP_frame,es mov ax,cs ; switch the to our stack mov ss,ax lea sp,stack_top mov ds,ax mov es,ax call clear_uninitialized_data mov ds,cs:PSP_frame cld lea si,PSP_DTA+1 lea di,comline+1 mov cl,PSP_DTA xor ch,ch jcxz start__2 start__: ; skip leading blanks cmp byte ptr [si],' ' jne start__2 inc si loop start__ start__2: mov comline-1,ch mov comline,cl inc cx ; get the CR too rep movsb ; get the commandline out of psp push cs pop ds assume ds:code ; from now on we have CS=DS=ES=SS ; make sure that size byte is correct ; ( some DOS versions set only CR .. sometimes ) lea di,comline+1 mov al,13 call strlen cmp al,comline jnb start_0 mov comline,al start_0: mov bx,word ptr comline-1 xchg bh,bl mov comline[bx+1],0 ; replace CR by ZERO mov logo_out,0 mov print_dots,0 mov kernel_start,kernel_start_ ; real kernel_start mov free_mem_start,cs ;save CS as later freemem ; now check if (on error) we can exit do DOS lea bx,comspec_tx call get_env_variable ; we expect COMSPEC= in the environement mov al,byte ptr es:[di] mov can_exit_to_dos,al ; check if we are running under windows lea bx,windows_tx call get_env_variable ; we expect WINDIR= in the environement mov al,byte ptr es:[di] mov cannot_load_because_of_windows,al push ds pop es lea ax,modul_end+15 shr ax,4 mov bx,ax add ax,High_Seg mov es,PSP_frame cmp ax,es:PSP_memend_frame jnb err_uppermem push ds pop es ; restore es mov ax,free_mem_start mov kernel_load_frame,ax cmp ax,kernel_start jnb start_1 mov ax,kernel_start mov kernel_load_frame,ax start_1: ; check if we are on the right CPU mov cpu_check_status,0 call cpu_check lea dx,err_wrong_cpu_tx cmp ax,cpu_386V86 jb err_print ; has no 386 or greater at all .386 ; now we are sure beeing on a 386(and greater) CPU m2: call parscommandline call cpu_check ; do it once more, because of option_clone mov cpu_check_status,2 call get_default_bios_intvectors cmp ax,cpu_386GE jb m2_1 test intv_size,0fffch jnz start_continue ; has $BIOSINTV or REALBIOS.INT cmp option_t_forced,0 jnz start_continue mov have_to_intercept_setup,1 jmp start_continue m2_1: mov cpu_check_status,4 ; have 386, but are in V86-mode call check_VCPI_present jz err_wrong_cpu ; has no VCPI-server mov cpu_check_status,6 call check_low_mem_mapping jz err_wrong_cpu ; has no identical phys/log mapping mov have_to_force_realmode,1 test intv_size,0fffch jnz plain_switch ; has $BIOSINTV or REALBIOS.INT ; has no $BIOSINTV driver loaded ; but will try to start Linux anyway cmp option_t_forced,0 jnz plain_switch mov word ptr cs:intv_buf+(4*15h+2),0 mov have_to_intercept_setup,1 plain_switch: mov cpu_check_status,8 start_continue: cmp comline,0 ; have we an emtpy string ? jnz m3 lea dx,empty_tx jmp err_print ; have file-name at minimum ; trying to open it m3: mov ax,DOS_OPEN_FILE shl 8 lea dx,image_name DosInt jnc fileopened m4: lea dx,err_file_notfound_tx m4_: call print lea dx,enter_commandline_tx call print call readstring cmp comline,0 ; have we an emtpy string ? jnz m2 lea dx,abort_tx call print jmp err_exit fileopened: mov fhandle,ax ; first look if it is really an image mov bx,ax mov ecx,512 mov di,cs call read_handle ; read the bootsector jnc have_bootsect fileopened_wrong: DosCall DOS_CLOSE_FILE lea dx,err_wrong_file_tx jmp m4_ err_wrong_setup: DosCall DOS_CLOSE_FILE lea dx,err_wrong_setup_tx jmp m4_ err_setup_too_long: DosCall DOS_CLOSE_FILE lea dx,err_setup_too_long_tx jmp m4_ have_bootsect: cmp ax,cx jne fileopened_wrong cmp bootmagic,0AA55h jne fileopened_wrong ; ok, now get the setup part mov di,cs lea bx,setup_prog shr bx,4 add di,bx mov bx,fhandle xor ecx,ecx mov ch,setup_sects shl cx,1 jnz new_bootsect mov ch,2*standard_setup_sects new_bootsect: cmp cx,maximum_setup_sects*512 ja err_setup_too_long mov new_setup_size,cx call read_handle ; read setup jc fileopened_wrong cmp ax,cx jne fileopened_wrong cmp have_to_intercept_setup,0 jz dont_patch cmp dword ptr ds:setup_header_sign,SIGNATURE jnz not_signed mov have_to_intercept_setup,2 mov word ptr ds:setup_realmode_switch,offset real_switch mov word ptr ds:setup_realmode_switch+2,High_Seg mov ax,kernel_load_frame mov word ptr ds:start_sys_seg,ax jmp dont_patch not_signed: xor di,di mov cx,new_setup_size mov al,0FAh ; cli cld keep_searching: repnz scasb jcxz err_wrong_setup cmp dword ptr [di],70E680B0h ; mov al,80h ; out 70h,al jnz keep_searching mov byte ptr [di-1],0CDh ; int op code mov byte ptr [di],setup_intercept_int ; int number mov word ptr [di+1],4444h ; inc sp adjust stack ; inc sp (discard flags) mov byte ptr [di+3],90h ; nop dont_patch: ; we convert the kernel version string ; to a binary number xor eax,eax cmp have_to_intercept_setup,2 jne dont_patch_ call get_kernel_version dont_patch_: mov kernelversion,eax call handle_kernel_specifics ; ok, now check the size of the kernel mov ax,High_Seg sub ax,kernel_load_frame cmp ax,kernel_size ja have_space lea dx,err_kernel_to_big_tx cmp option_t,0 je err_print have_space: ; now we update the params cmp command_line,0 jz no_comline mov CL_MAGIC,0A33Fh lea ax,command_line mov CL_OFFSET,ax mov si,cl_pointer mov byte ptr [si-1],0 ;delete the last blank no_comline: ; check for ramdisk cmp got_ram_disk,0 jz no_change_on_ramdisk mov ax,new_ram_disk mov ram_disk,ax no_change_on_ramdisk: ; check for vga cmp got_vga_mode,0 jz no_change_on_vga mov ax,new_vga_mode mov vga_mode,ax no_change_on_vga: ; check for ro_flag cmp got_ro_flag,0 jz no_change_on_ro mov ax,new_ro_flag mov ro_flag,ax no_change_on_ro: ; check for root_dev cmp got_root_dev,0 jz no_change_on_root_dev mov ax,new_root_dev mov root_dev,ax no_change_on_root_dev: cmp cannot_load_because_of_windows,0 jz no_windows call force_error_verbose no_windows: ; check for -v option cmp option_v,0 jz no_option_v ; option -v (verbose) is set ; print some information call print_verbose no_option_v: ; check for -t option cmp option_t,0 jz no_option_t DosCall DOS_CLOSE_FILE lea dx,option_t_terminate_tx cmp option_t_forced,0 jz no_option_t_forced lea dx,option_t_forced_tx no_option_t_forced: call print jmp err_exit no_option_t: ; start of critical section ; ========================= call close_debug_file ;--------------------------------------- mov ax,High_Seg ; move us high mov es,ax push cs pop ds xor si,si xor di,di lea cx,modul_end+3 shr cx,2 rep movsd push es pop ds ; we have move ourself up ; must now change cs push ds lea ax,back_from_low push ax retf back_from_low: mov ax,ds ; switch the stack to top mov ss,ax lea sp,stack_top ; from now on we have CS=DS=ES=SS=setup_memory ;------------------------------------------- cmp have_to_force_realmode,0 je back_from_low_continue ; we have to do this once more ; because some VCPI-servers rely on an unmovable page0 call get_VCPI_interface back_from_low_continue: ; now loading the kernel mov bx,fhandle movzx ecx,kernel_size shl ecx,4 mov di,kernel_load_frame mov print_dots,2 call read_handle ; read the kernel call print_crlf mov print_dots,0 call print_crlf jc err_io add eax,15 and al,0f0h cmp eax,ecx jnz fileopened_wrong ; ok, all is read into memory DosCall DOS_CLOSE_FILE cmp ram_disk,0 ; have we a ramdisk jz no_ram_disk cmp option_nodiskprompt,0; jnz no_ram_disk ;we must prompt for insertion of floppy lea dx,insert_floppy_tx call print call readstring ; just to wait for prompt no_ram_disk: cli ___go: cmp have_to_intercept_setup,1 ja ___go_switch je ___go_skip_move call move_kernel_down ___go_skip_move: cmp have_to_intercept_setup,1 jne ___go_switch xor ax,ax mov ds,ax mov word ptr ds:[4*setup_intercept_int],offset real_switch mov word ptr ds:[4*setup_intercept_int+2],cs ___go_switch: mov ax,High_Seg mov ds,ax mov es,ax cmp have_to_intercept_setup,0 ja ___go_continue call switch_to_protected_mode_and_return_in_386realmode ___go_continue: call restore_bios_default_vectors lea bx,setup_prog shr bx,4 mov ax,High_Seg add ax,bx lea sp,setup_stack_top ; separate stack during ; setup and real_switch push ax push 0 mov ax,root_dev retf ; and now it's the job of setup ; but NOTE: ; on have_to_force_realmode >0 setup calls real_switch setup_own_stack df 0 real_switch proc far ; NOTE: we have to preserve ALL registers ! ; to avoid conflicts with future kernels cli push_ ds,es,fs,gs pushad mov al,80h out [70h],al mov ax,cs mov ds,ax mov es,ax mov word ptr setup_own_stack+4,ss mov dword ptr setup_own_stack,esp ; Ok,ok, today setup has our stack (no need to switch) mov ss,ax ; ... but we want to be sure for the future, lea sp,stack_top ; so we switch to our stack cmp have_to_intercept_setup,2 ; have we to move the kernel down ? je @@3 ; no, setup will do it (knows the location of the image) ; yes, we have patched in the intercept code, ; so the kernel expects the kernel at 10000h call move_kernel_down @@3: call switch_to_protected_mode_and_return_in_386realmode lss esp,cs:setup_own_stack ; restore setup's stack popad pop_ ds,es,fs,gs retf real_switch endp ;============================================================================= move_kernel_down proc near ; is the kernel at its right place ? cli mov ax,kernel_start cmp kernel_load_frame,ax je short @@ex ; yes ; no, must move it down push_ ds,es cld mgran = 08000h mov bp,mgran shr 4 mov ax,kernel_size mov bx,kernel_start mov dx,kernel_load_frame @@loop: mov cx,mgran shr 2 mov ds,dx mov es,bx xor si,si xor di,di rep movsd add bx,bp add dx,bp sub ax,bp cmp ax,bp ja @@loop mov cx,ax shl cx,2 mov ds,dx mov es,bx xor si,si xor di,di rep movsd IF 0 ; I guess, it's not needed ; now clear the space behind the kernel (BSS) @@clear: push cs pop ds mov bp,mgran shr 4 mov bx,kernel_start add bx,kernel_size mov dx,High_Seg xor eax,eax sub dx,bx ; count of remaining space jc @@ex0 jmp @@ctest @@cloop: mov cx,mgran shr 2 mov es,bx xor di,di rep stosd add bx,bp sub dx,bp @@ctest: cmp dx,bp ja @@cloop mov cx,dx shl cx,2 mov es,bx xor di,di rep stosd @@ex0: ENDIF pop_ ds,es mov ax,kernel_start mov kernel_load_frame,ax @@ex: ret move_kernel_down endp err_wrong_cpu: lea dx,err_cpu_v86_tx err_print: cmp word ptr comline-1,0 ; have we an command line jnz err_print_2 ; no ; yes, print help and status push dx lea dx,usage_tx call print pop dx err_print_2: call print cmp cpu_type,cpu_386V86 jb err_exit call print_verbose_stat jmp err_exit err_io: lea dx,err_io_tx call print jmp err_exit err_uppermem: lea dx,err_uppermem_tx call print err_exit: cmp cs:can_exit_to_dos,0 jz idle mov al,1 exit_to_dos: call close_debug_file DosCall DOS_TERMINATE_EXE idle: lea dx,err_in_config_sys_tx call print call close_debug_file idle_: sti jmp idle_ real_print proc near ; input: DX = offset of string within CODE .8086 push ds push cs pop ds push_ bx,cx,si mov si,dx cld xor ax,ax @@loop: lodsb test ax,ax jz @@ok cmp al,'$' jnz @@loop @@ok: dec si sub si,dx jz @@null mov cx,si mov bx,1 DosCall DOS_WRITE_TO_HANDLE cmp debug_file_handle,0 jz @@ex mov bx,debug_file_handle DosCall DOS_WRITE_TO_HANDLE @@null: @@ex: pop_ bx,cx,si pop ds ret .386 real_print endp print proc near cmp cs:logo_out,0 jnz @@ex mov cs:logo_out,1 push_ ax,dx lea dx,logo_tx call real_print pop_ ax,dx @@ex: call real_print ret print endp print_crlf proc near pushf push ax push dx lea dx,@@crlf call print pop dx pop ax popf ret @@crlf db 13,10,'$' print_crlf endp print_dot proc near pushf cmp cs:print_dots,1 jb @@ex push ax push dx lea dx,@@dot_tx je @@1 lea dx,@@start_tx dec cs:print_dots @@1: call print pop dx pop ax @@ex: popf ret @@start_tx db 13,10,'LOADING' @@dot_tx db '.$' print_dot endp read_handle proc near ; input: ; BX= handle ; ECX= count ; DI= frame of destination ; output: ; CARRY =1 , then read-error ; EAX= number of bytes transferred (even on CARRY=1) ; granularity = 02000h push ds push esi push dx push ecx mov ds,di mov esi,ecx mov ecx,granularity xor dx,dx jmp @@start @@next: DosCall DOS_READ_FROM_HANDLE call print_dot jc @@err cmp ax,cx jne @@eof sub esi,ecx mov ax,ds add ax,(granularity shr 4) mov ds,ax @@start: cmp esi,ecx ja @@next mov cx,si DosCall DOS_READ_FROM_HANDLE call print_dot jc @@err @@eof: movzx eax,ax sub esi,eax pop ecx mov eax,ecx sub eax,esi clc @@ex: pop dx pop esi pop ds ret @@err: pop ecx mov eax,ecx sub eax,esi stc jmp @@ex read_handle endp read_comline_from_file proc near ;; mov ax,DOS_OPEN_FILE shl 8 ;; lea dx,image_name+1 ;; DosInt push fs call @@open jnc @@isopen @@err: lea dx,err_comfile_tx call print mov word ptr comline-1,0 jmp @@ex @@ioerr: ;; DosCall DOS_CLOSE_FILE call @@close jmp @@err @@isopen: mov bx,ax cld lea di,comline+1 @@loop: mov dx,di mov cx,1 ;; DosCall DOS_READ_FROM_HANDLE call @@read jc @@ioerr cmp ax,1 jne @@eof mov al,byte ptr [di] cmp al,13 je @@loop cmp al,'#' je @@skipeol @@skipcontinue: inc di cmp di, offset comline_end-1 jnb @@eof cmp al,' ' ja @@loop cmp di,offset comline+2 jna @@1 cmp byte ptr [di-2],' ' ; ignore multiple spaces jne @@1 dec di jmp @@loop @@1: mov byte ptr [di-1],' ' jmp @@loop @@eof: mov byte ptr [di],0 mov ax,di sub ax,offset comline+1 xchg al,ah mov word ptr comline-1,ax ;; DosCall DOS_CLOSE_FILE call @@close jmp @@ex @@skipeol: mov dx,di mov cx,1 ;; DosCall DOS_READ_FROM_HANDLE call @@read jc @@ioerr cmp ax,1 jne @@eof cmp byte ptr [di],10 jne @@skipeol jmp @@skipcontinue @@ex: pop fs ret ; ----------- @@virtual db 0 @@open: ; virtual open routine cmp dword ptr image_name,'ol@@' jne @@open_d cmp dword ptr image_name+4,'ilda' jne @@open_d cmp dword ptr image_name+4+4,'@@xn' je @@open_v @@open_d: mov @@virtual,0 lea dx,image_name+1 mov ax,DOS_OPEN_FILE shl 8 DosInt ret @@open_v: mov @@virtual,1 mov ax,High_Seg mov fs,ax lea ax,params_from_loadlinX clc ret @@close: cmp @@virtual,0 jz @@close_d ret @@close_d: DosCall DOS_CLOSE_FILE ret @@read: cmp @@virtual,0 jz @@read_d mov al, byte ptr fs:[bx] or al,al jz @@read_eof inc bx mov byte ptr [di],al mov ax,1 clc ret @@read_eof: xor ax,ax clc ret @@read_d: DosCall DOS_READ_FROM_HANDLE ret read_comline_from_file endp check_token proc near ; input: ; ES=DS=CS= seg of all pointers ; DI = pointing to token ; BX = pointing to string-table, terminated by a ZERO-string ; output: ; AX = -1, no match found ; = 0, found a matching string, BX = index*2 of that string ; = 1, same as AX=0, but token was terminated by '=' ; DI = pointing to token behind terminator (0 or '=') ; push_ cx,dx cld xor dx,dx jmp @@loop_entry @@loop: pop di inc dx xchg bx,di xor ax,ax mov cx,-1 repnz scasb ; skip to next string in table xchg bx,di cmp byte ptr [bx],0 jz @@not_found @@loop_entry: push di mov cx,size aux_token call name_compare jz @@loop pop ax ; clean up stack xchg dx,bx ; get index shl bx,1 xor ax,ax cmp byte ptr [di-1],'=' jne @@ex inc ax @@ex: pop_ cx,dx test ax,ax ret @@not_found: mov ax,-1 jmp @@ex check_token endp clear_to_default proc near push_ ax,di,es call close_debug_file push cs pop es xor ax,ax mov cx,parse_switches_end-parse_switches lea di,parse_switches cld rep stosb pop_ ax,di,es ret clear_to_default endp ;============================================================================= INCLUDE LOADLINI.ASM ;============================================================================= ; ------------------------------------------------------------- clear_uninitialized_data proc near .8086 push_ ax,cx,di xor ax,ax lea di,uninitialized_data_start mov cx,(uninitialized_data_stop-uninitialized_data_start)/2 cld rep stosw mov ax,word ptr pagedir_template mov word ptr pagedir,ax mov ax,word ptr pagedir_template+2 mov word ptr pagedir+2,ax pop_ ax,cx,di ret .386 clear_uninitialized_data endp align dword db space1k dup(?) setup_stack_top label byte db space1k dup(?) stack_top label byte uninitialized_data_start label byte db ? ; belongs to comline comline db 128 dup(?) ; copied from PSP_DTA db 2*1024-128 dup(?) ; extended commandline comline_end label byte image_name db 80 dup(?) aux_token db 80 dup(?) command_line db space2k dup(?) ; kernel accepts maximum of 2Kb ; -------------------------------v ; this buffer is for the "default bios interruptvectors" ; as is set from the BIOS, ; Its contents are delivered by the BIOSINTV.SYS device driver ; (must be AT TOP of config.sys). ; Or from the REALBIOS.INT file. ; We need this after returning from V86-mode ; because NOTHING is valid any more but the ROM-BIOS ; (and LOADLIN of cause) ; intv_buf dd 128 dup(?) ; intvector 0:0 dd 128 dup(?) bios_data db 256 dup(?) ; BIOS-data 40:0 dummy_dos_data db (256-4-16-2) dup(?) ; (DOS-data 50:0, not valid at boot tome real_bios_int15 dw ? ; result of int15 at time of realbios real_bios_magic dw ? ; must be 0a5a5h for post alpha-release reset_jmpop db ? ; TOP BIOS FFFF:0 reset_entry dd ? biosdate db 9 dup(?) machineid db ? db ? masterIMR db ? ; port 21 slaveIMR db ? ; port A1 bios_scratch db 1024 dup(?) ; scratch 9FC0:0 realbios_end label byte ; -------------------------------^ ; -------------------------------v align_ code_org0,4096 IF 0 ; now moved at start of our code ; (overlapping our code) pagedir dd 1024 dup(?) ; must be aligned to 4 K ENDIF page0 dd 1024 dup(?) ; must be aligned to 4 K ; -------------------------------^ uninitialized_data_stop label byte ; ------------------------------------------------------------- modul_end: code ends end start