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386INIT.ASM
executable file
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386INIT.ASM
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page ,132
title 386INIT.ASM
;
; 386 protected-mode control program
;
; 386INIT.ASM
; 386 protected-mode initialization module
;
; by Jeff Parsons 05-Jun-1992
; with a little help from Intel's 386 Programmer's Reference Manual :)
;
;
; When this module is assembled and linked as a .COM file, the segments
; must be arranged by the linker as follows:
;
; _TEXT16
; _TEXT
; _DATA16
; _DATA
;
; This unusual mingling of 16-bit and 32-bit segments occurs because
; both code segments are of class "CODE" and both data segments are of
; class "DATA". This makes it easy for the _TEXT16 segment to determine
; where the _TEXT segment begins (ie, on the next paragraph boundary
; after the end of the _TEXT16 segment). Likewise for the data segments.
;
; After we switch into protected-mode and have access to the complete
; physical address space, we build the following data structures @ 1Mb+64Kb:
;
; Resident code (@SEL_TEXT:?)
; Resident data (@SEL_DATA:?)
; IDT ( 30h*8 == 180h bytes)
; TSS ( == 2068h bytes)
; GDT ( 5*8 == 28h bytes)
; PgDir x 1 (4*1024*1 == 1000h bytes) @page boundary
; PgTbl x n (4*1024*n == 1000h*n bytes) @page boundaries
; Stack ( == 2000h bytes)
; Alias to first MB
;
__acrtused equ 1
public __acrtused
include all.inc
ORG_VALUE equ 100h ; for .COM file
PHYS_TEXT equ 00110000h ; physical address for resident _TEXT (1Mb+64Kb)
STACK_SIZE equ 8192
GRP16 group _TEXT16,_DATA16
;
; Insure that _TEXT16 is the first segment in the image file
; (although MASM6 seems to do the right thing anyway)
;
_TEXT16 segment para public 'CODE'
_TEXT16 ends
_DATA16 segment para public 'DATA'
SEGLIMIT_DEFAULT equ (SEGLIMIT_GRANULAR or SEGLIMIT_BIG or 0Fh)
;
; Temporary GDT. This is what we're running on when we first
; enter protected-mode. The "?" fields have to be filled in at
; run-time, because this .COM file can be loaded anywhere in low memory
;
public adesGDT ; GDT array of descriptors
adesGDT label byte
public desNull ; the first descriptor should be NULL
desNull DES <0,0,0,0,0,0> ; (for errata mostly I think)
public desFlat ; the second descriptor is for all of memory
desFlat DES <0FFFFh,0,0,SEG_DATA,SEGLIMIT_DEFAULT,0>
public SEL_FLAT
SEL_FLAT equ desFlat-desNull
public desText ; the third descriptor is for the _TEXT seg.
desText DES <0FFFFh,?,?,SEG_CODE,SEGLIMIT_DEFAULT,0>
public SEL_TEXT
SEL_TEXT equ desText-desNull
public desData ; the fourth descriptor is for the _DATA seg.
desData DES <0FFFFh,?,?,SEG_DATA,SEGLIMIT_DEFAULT,0>
public SEL_DATA
SEL_DATA equ desData-desNull
public desCode ; the fifth descriptor is for scratch code seg
desCode DES <0FFFFh,?,?,SEG_CODE,SEGLIMIT_DEFAULT,0>
public SEL_CODE
SEL_CODE equ desCode-desNull
public desTSS ; the fifth descriptor is for the TSS
desTSS DES <size TSS-1,?,?,SEG_386TSS,0,0>
public SEL_TSS
SEL_TSS equ desTSS-desNull
public adesGDTend ; end of this GDT
adesGDTend label byte
public GDT_SIZE
GDT_SIZE equ adesGDTend-adesGDT
public dtrGDTTmp ; initial setting for GDTR register
dtrGDTTmp DTR <GDT_SIZE-1, ?>
public bSwitches
bSwitches db 0
SW_REBOOT equ 0001h ; /R
SW_50LINES equ 0002h ; /50
szHelp db "386 Monitor",CR,LF
db "By Jeff Parsons 05-Jun-1992",CR,LF
db LF
db "Command-line options",CR,LF
db " /? This message",CR,LF
db " /R Reset via reboot (incompatible w/386Max)",CR,LF
db " /50 Enable 50-line debugger display",CR,LF
db LF
db "After loading, use '?' to display debugger commands",CR,LF
db '$'
szBad386 db "Not a 386-compatible processor",CR,LF,'$'
align 16
public __DataStart
__DataStart label byte
_DATA16 ends
;
; To transfer control from Init16 to Init32, I really want to say:
;
; jmp far ptr SEL_TEXT:0
;
; but since MASM won't let me do that, I've created these "template
; segments" (hence the prefix T) that allow me to code far jumps that
; don't need segment fixups.
;
TEXT16 segment at 0
TFar16 label far
TEXT16 ends
DefCode macro none
CODE segment at SEL_CODE
ifb <none>
org __TextStart-Init16 + ORG_VALUE
TInit32 label far
endif
CODE ends
endm
DefText macro none
TEXT segment at SEL_TEXT
ifb <none>
org __TextStart-Init16 + Main32-Init32 + ORG_VALUE
TMain32 label far
endif
TEXT ends
endm
DefCode None
DefText None
_TEXT16 segment para public 'CODE'
org ORG_VALUE
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Init16
;
; 16-bit initialization entry point
;
; We want to take over the machine. The whole machine. But we
; want to do it somewhat gracefully; we don't want to leave disk
; caches unflushed, for example. And some drivers make life hard for
; us, like EMM386, which may be running the processor in protected-
; mode already (ie, v86-mode).
;
; INT 19h (REBOOT_INT) to the rescue! All the drivers we're
; worried about should (in theory) have hooked INT 19h and be able to
; flush, unhook, or unload whatever they need to flush, unhook or
; unload. The only problem is that we lose control too!
;
; But, there's a undocumented location (106h) in the DOS BIOS data
; segment (70h) that contains the original INT 13h disk vector address,
; which is what DOS restores the disk vector to when *it* sees an
; INT 19h. So we edit that field so that DOS restores INT 13h to point
; to us, and as soon as we see an INT 13h that's about to start the
; boot process, we take over, so you never even see any disk boot
; activity.
;
; A reasonably elegant, surprisingly simple, and only mildly hacky
; solution.
;
; ENTRY
; None
;
; EXIT
; Never
;
; USES
; All
;
assume cs:GRP16,ds:GRP16,es:GRP16,ss:GRP16
public Init16
Init16 proc far
sub ax,ax
mov si,psp_cbCommand
lodsb
mov cx,ax ; CX == length of command tail
do_char:
lodsb
try_char:
cmp al,CR ; end of the line?
je short init ; yes
cmp al,'/' ; switch char?
je short do_switch ; yes
cmp al,'-' ; switch char?
jne short next_switch ; no
do_switch:
lodsb ;
cmp al,'?' ; /? help switch?
jne short not_? ; no
mov dx,offset GRP16:szHelp
mov ah,DOS_STD_CON_STRING_OUTPUT
int INT_DOS
int INT_DOSEXIT
not_?:
cmp al,'5' ; /50 line switch?
jne short not_50 ; no
lodsb ;
cmp al,'0' ;
jne short try_char ;
or [bSwitches],SW_50LINES
jmp short next_switch ;
not_50:
and al,not LC_BIT
cmp al,'R' ; /R reboot switch?
jne short next_switch ; no
or [bSwitches],SW_REBOOT
next_switch:
loop do_char
;
; Check processor type
;
init:
Check286
je short init_86 ; it's pre-286 (808x or 8018x)
Check386
jnz short init_386 ; it's 386 or better
init_86:
mov dx,offset GRP16:szBad386
mov ah,DOS_STD_CON_STRING_OUTPUT
int INT_DOS
int INT_DOSEXIT
init_386:
.386c
mov ah,DOS_DISK_RESET ; try to insure that all disk
int INT_DOS ; buffers are flushed
.errnz SEG_ROMDATA ;
sub ax,ax ; AX == SEG_ROMDATA
mov ds,ax ;
mov es,ax ;
assume ds:_ROMDATA,es:_ROMDATA
mov al,RomData.rb_vga.vga_CRTRows
test [bSwitches],SW_50LINES
;;; jz short init_notforced
jz short init_not50 ; for now, no /50 means no video mucking
mov al,50-1 ; force 50-line mode
init_notforced:
push ax ; save current # of rows
mov ax,VIDEO_RESET shl 8 or VMODE_CO80
int INT_VIDEO ; reset the video mode
pop ax ; recover original # of rows
cmp al,50-1 ; 50-line mode?
jne short init_not50 ; no
mov ax,VIDEO_EGASELECTFONT shl 8 or VFONT_8X8
mov bl,0 ; load 8x8 font in block #0
int INT_VIDEO ;
mov cx,0 shl 8 or 7 ; CH=0, CL=7 (scan lines)
mov ah,VIDEO_SETCURSORTYPE
int INT_VIDEO ; block cursor enabled
init_not50:
test [bSwitches],SW_REBOOT
jz short init_reset ;
;
; This is the original, hacky way I tried forcing a transition
; back to real-mode if currently in v86-mode, but it doesn't work
; well with software like 386MAX
;
mov ax,SEG_DOSDATA
mov ds,ax
assume ds:_DOSDATA
mov eax,[DosData].dos_OldInt13
mov dword ptr [Int13Vector],eax
mov [DosData].dos_OldInt13.w_lo,offset GRP16:Int13Hook
mov [DosData].dos_OldInt13.w_hi,cs
int INT_REBOOT ; start warm boot
Int13Hook:
assume ds:nothing,es:nothing,ss:nothing
cmp ah,DISKIO_RESET ; disk reset?
je short InitContinue ; yes, take control
Int13Vector equ $+1
jmp far ptr TEXT16:TFar16
;
; This is the new, improved way: reset the processor and get control
; back from the ROM immediately using the appropriate CMOS shutdown code
;
init_reset:
assume ds:_ROMDATA,es:_ROMDATA,ss:GRP16
cli
SumVecs ; vector chksum ok?
jne short init_vecset ; no
CopyVecs ; copy vectors back into the IVT
init_vecset:
mov al,0FFh ; don't take any chances, shut off
out PIC_SLAVE_IMR,al ; all interrupts
out PIC_MASTER_IMR,al ;
mov [RomData].rb_IOROMInit.w_lo,offset GRP16:InitContinue
mov [RomData].rb_IOROMInit.w_hi,cs
ResetCPU CMOSSHUTDOWN_FARJMP
public InitContinue
InitContinue label far
assume ds:nothing,es:nothing,ss:nothing
cli
cld
.errnz SEG_ROMDATA ; AX == SEG_ROMDATA
sub ax,ax ; zero all segments in preparation
mov ds,ax ; for transition to protected-mode
mov es,ax ; (not clear this is necessary though)
mov fs,ax
mov gs,ax
mov ss,ax ; all we need this stack for is
mov sp,400h ; for the few calls below (very temporary)
assume ds:_ROMDATA,es:_ROMDATA,ss:_ROMDATA
test [bSwitches],SW_REBOOT
jz short init_a20
mov eax,dword ptr [Int13Vector]
mov [RomData].rb_IVT[INT_DISKIO*4],eax
;
; Ensure A20 enabled
;
init_a20:
call WaitKbdInput16
mov al,KBDCMD_WRITE_OPORT
out KBDPORT_STATUS,al
call WaitKbdInput16
mov al,KBDOPORT_A20ON
out KBDPORT_DATA,al
call WaitKbdInput16
;
; Set fast typematic rate
;
mov al,KEYCMD_SETTYPEMATIC
out KBDPORT_DATA,al ; tell keyboard to set new typematic rate
call WaitKbdOutput16 ; wait for acknowledgement
in al,KBDPORT_DATA ; get it
mov al,TYPEMATIC_FAST ; select rate (bits 0-4), delay (bits 5-6)
out KBDPORT_DATA,al ;
call WaitKbdOutput16 ; wait for acknowledgement
in al,KBDPORT_DATA ; get it
ifdef KBDSCAN3
;
; Enable scan code set #3
;
mov al,KEYCMD_SETSCANSET
out KBDPORT_DATA,al ; tell keyboard to enable new scan set
call WaitKbdOutput16 ; wait for acknowledgement
in al,KBDPORT_DATA ; get it
mov al,3 ; select scan set #3
out KBDPORT_DATA,al ;
call WaitKbdOutput16 ; wait for acknowledgement
endif ;KBDSCAN3
SetPICs <IRQ_TMR,IRQ_KBD> ; set PICS for protected-mode operation
; w/TMR and KBD interrupts
;
; Determine initial CS:IP for v86-mode, by setting _v86Init @__DataStart
;
mov cs:[__DataStart].w_lo,offset v86Init
mov cs:[__DataStart].w_hi,cs
;
; Create temporary GDT
;
mov ax,cs
movzx eax,ax
mov edx,eax ; EDX -> CS:0
shl eax,4
mov [desText].des_wBase0_15,ax
mov [desCode].des_wBase0_15,ax
shr eax,16
mov [desText].des_bBase16_23,al
mov [desCode].des_bBase16_23,al
mov eax,edx
shl eax,4
add eax,offset GRP16:__DataStart
mov [desData].des_wBase0_15,ax
shr eax,16
mov [desData].des_bBase16_23,al
shl edx,4
add edx,offset GRP16:adesGDT
mov [dtrGDTTmp].dtr_dwBase,edx
.386p ; we're not quite there yet, but make masm happy
lgdt [dtrGDTTmp]
mov eax,cr0 ;
or eax,CR0_PE ; switch to protected mode
mov cr0,eax ; DONE!
; now jump to flush the prefetch and
; load our new, cool 32-bit code selector
jmp far ptr CODE:TInit32
public v86Init
v86Init label near
int INT_REBOOT
Init16 endp
public WaitKbdInput16
WaitKbdInput16 proc near
sub cx,cx
wait_loop:
in al,KBDPORT_STATUS
test al,KBDSTATUS_INPUT
loopnz wait_loop
ret
WaitKbdInput16 endp
public WaitKbdOutput16
WaitKbdOutput16 proc near
sub cx,cx
wait_loop:
in al,KBDPORT_STATUS
test al,KBDSTATUS_OUTPUT
loopz wait_loop
ret
WaitKbdOutput16 endp
align 16
public __TextStart
__TextStart:
_TEXT16 ends
DefCode ; define TInit32 for far transfer now
.386p
OPEN_CODE
extrn DivError:near
extrn Debug:near
extrn NMI:near
extrn BreakPoint:near
extrn Overflow:near
extrn Bounds:near
extrn InvOpCode:near
extrn NoCP:near
extrn DblFault:near
extrn TSSFault:near
extrn SegFault:near
extrn StackFault:near
extrn GPFault:near
extrn PageFault:near
extrn CPFault:near
extrn UnknownFault:near
extrn TMRInterrupt:near
extrn KBDInterrupt:near
extrn IRQ2Interrupt:near
extrn IRQ3Interrupt:near
extrn IRQ4Interrupt:near
extrn IRQ5Interrupt:near
extrn IRQ6Interrupt:near
extrn IRQ7Interrupt:near
extrn IRQ8Interrupt:near
extrn IRQ9Interrupt:near
extrn IRQAInterrupt:near
extrn IRQBInterrupt:near
extrn IRQCInterrupt:near
extrn IRQDInterrupt:near
extrn IRQEInterrupt:near
extrn IRQFInterrupt:near
CLOSE_CODE
OPEN_DATA
CLOSE_DATA
CONST segment dword use32 public 'CONST'
CONST ends
_STATIC segment dword use32 public 'STATIC'
public __StaticDataEnd
__StaticDataEnd label byte
_STATIC ends
_BSS segment dword use32 public 'BSS'
_BSS ends
c_common segment dword use32 public 'BSS'
c_common ends
DATA GROUP _DATA, CONST, _STATIC, _BSS, c_common, _EDATA
OPEN_DATA
; memmgr.c globals
extrn _pmbZero:dword
public _v86Init
_v86Init dd 0 ; must be 1st dword in _DATA, @__DataStart
public aoffIDTInit
aoffIDTInit dd DivError ; IDT_DIVERROR 0x00
dd Debug ; IDT_DEBUG 0x01
dd NMI ; IDT_NMI 0x02
dd BreakPoint ; IDT_BREAKPOINT 0x03
dd Overflow ; IDT_OVERFLOW 0x04
dd Bounds ; IDT_BOUNDS 0x05
dd InvOpCode ; IDT_INVOPCODE 0x06
dd NoCP ; IDT_NOCP 0x07
dd DblFault ; IDT_DBLFAULT 0x08
dd UnknownFault ; IDT_RESERVED09 0x09
dd TSSFault ; IDT_TSSFAULT 0x0A
dd SegFault ; IDT_SEGFAULT 0x0B
dd StackFault ; IDT_STACKFAULT 0x0C
dd GPFault ; IDT_GPFAULT 0x0D
dd PageFault ; IDT_PAGEFAULT 0x0E
dd UnknownFault ; IDT_RESERVED0F 0x0F
dd CPFault ; IDT_CPFAULT 0x10
dd UnknownFault ; IDT_RESERVED11 0x11
dd UnknownFault ; IDT_RESERVED12 0x12
dd UnknownFault ; IDT_RESERVED13 0x13
dd UnknownFault ; IDT_RESERVED14 0x14
dd UnknownFault ; IDT_RESERVED15 0x15
dd UnknownFault ; IDT_RESERVED16 0x16
dd UnknownFault ; IDT_RESERVED17 0x17
dd UnknownFault ; IDT_RESERVED18 0x18
dd UnknownFault ; IDT_RESERVED19 0x19
dd UnknownFault ; IDT_RESERVED1A 0x1A
dd UnknownFault ; IDT_RESERVED1B 0x1B
dd UnknownFault ; IDT_RESERVED1C 0x1C
dd UnknownFault ; IDT_RESERVED1D 0x1D
dd UnknownFault ; IDT_RESERVED1E 0x1E
dd UnknownFault ; IDT_RESERVED1F 0x1F
dd TMRInterrupt ; IDT_TMR 0x20
dd KBDInterrupt ; IDT_KBD 0x21
dd IRQ2Interrupt ; IDT_SLAVE 0x22
dd IRQ3Interrupt ; IDT_COM2 0x23
dd IRQ4Interrupt ; IDT_COM1 0x24
dd IRQ5Interrupt ; IDT_LPT2 0x25
dd IRQ6Interrupt ; IDT_DISKETTE 0x26
dd IRQ7Interrupt ; IDT_LPT1 0x27
dd IRQ8Interrupt ; IDT_RTC 0x28
dd IRQ9Interrupt ; IDT_IRQ2 0x29
dd IRQAInterrupt ; IDT_IRQ10 0x2A
dd IRQBInterrupt ; IDT_IRQ11 0x2B
dd IRQCInterrupt ; IDT_IRQ12 0x2C
dd IRQDInterrupt ; IDT_CP 0x2D
dd IRQEInterrupt ; IDT_DISK 0x2E
dd IRQFInterrupt ; IDT_IRQ15 0x2F
public __ResDataStart
__ResDataStart label byte
public _sel_Flat,_sel_Text,_sel_Data
_sel_Flat dw SEL_FLAT
_sel_Text dw SEL_TEXT
_sel_Data dw SEL_DATA
public _pPhysData,_cbPhysData
_pPhysData dd ?
_cbPhysData dd ?
ifdef DEBUG
public _cbBSSData ; the linker doesn't fixup BSS data
_cbBSSData dd ? ; correctly, so we assert the size is zero
endif
public _dtrIDT,_pIDT
_dtrIDT DTR <IDT_SIZE-1, ?>
_pIDT dd ?
public _dtrGDT,_pGDT
_dtrGDT DTR <GDT_SIZE-1, ?>
_pGDT dd ?
public _pPhysTSS,_pTSS
_pPhysTSS dd ?
_pTSS dd ?
public _pPhysPgDir,_pPgDir
_pPhysPgDir dd ?
_pPgDir dd ?
public _pPhysPgTbl,_pPgTbl
_pPhysPgTbl dd ?
_pPgTbl dd ?
public _pPhysFree,_pLinFree,_pFree
_pPhysFree dd ?
_pLinFree dd ?
_pFree dd ?
CLOSE_DATA
_EDATA segment dword use32 public 'ENDDATA'
public __ResDataEnd
__ResDataEnd label byte
_EDATA ends
_ETEXT segment dword use32 public 'CODE'
public __ResTextEnd
__ResTextEnd label byte
_ETEXT ends
OPEN_CODE
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Init32
;
; 32-bit initialization entry point
;
; ENTRY
; EDX -> physical address of temporary GDT
;
; EXIT
; Never
;
; USES
; All
;
assume cs:CODE_SEG,ds:nothing,es:nothing,ss:nothing
public Init32
Init32 proc far
mov ax,SEL_DATA
mov ds,ax
assume ds:DATA_SEG
mov ax,SEL_FLAT
mov es,ax
mov edi,PHYS_TEXT ; ES:EDI -> resident code location
mov esi,offset __ResTextStart
mov ecx,offset __ResTextEnd
sub ecx,esi ;
rep movs byte ptr es:[edi],byte ptr cs:[esi]
mov [_pPhysData],edi ; ES:EDI -> resident data location
mov ebx,offset DATA:__ResDataStart
mov ecx,offset DATA:__ResDataEnd
sub ecx,ebx ;
mov [_cbPhysData],ecx ;
add edi,ecx ;
add ebx,ecx ;
mov [_dtrIDT].dtr_dwBase,edi
mov [_pIDT],ebx ;
mov ecx,IDT_ENTRIES ; 20h reserved + 10h physical interrupts
lea ebx,[ebx+ecx*8] ;
mov esi,offset aoffIDTInit
init_idt:
lodsd
mov es:[edi].gate_wBase0_15,ax
mov es:[edi].gate_wSel,SEL_TEXT
mov es:[edi].gate_bReserved,0
mov es:[edi].gate_bType,SEGTYPE_386INTGATE or SEGTYPE_DPL_0 or SEGTYPE_PRESENT
shr eax,16
mov es:[edi].gate_wBase16_31,ax
add edi,8
loop init_idt
mov [_pPhysTSS],edi ;
mov [_pTSS],ebx ;
sub eax,eax ;
mov ecx,size TSS/4 ;
lea ebx,[ebx+ecx*4] ;
rep stosd ; create empty TSS for now
mov [_dtrGDT].dtr_dwBase,edi
mov [_pGDT],ebx ;
mov esi,edx ; ESI -> GDT (from above)
mov ecx,GDT_SIZE/4 ;
lea ebx,[ebx+ecx*4] ;
rep movs dword ptr es:[edi],dword ptr es:[esi]
;
; The GDT probably has some room for growth, since the page directory
; which immediately follows must be located on a page boundary
;
mov edx,edi ;
add edi,PAGE_SIZE-1 ;
and edi,NOT (PAGE_SIZE-1)
mov cr3,edi ; ES:EDI -> resident page directory
mov [_pPhysPgDir],edi ;
mov eax,edi ;
sub eax,edx ;
add ebx,eax ;
mov [_pPgDir],ebx ;
lea eax,[edi+PAGE_SIZE] ;
or eax,PG_USER or PG_WRITE or PG_PRESENT
mov ecx,PAGE_ENTRIES ;
lea ebx,[ebx+ecx*4] ;
rep stosd ; for now, limit support to 4Mb
mov [_pPhysPgTbl],edi ;
mov [_pPgTbl],ebx ;
mov eax,PG_USER or PG_WRITE or PG_PRESENT
mov ecx,PAGE_ENTRIES ; ES:EDI -> first resident page table
lea ebx,[ebx+ecx*4] ;
init_pgtbl:
stosd ;
add eax,PG_FRAMEINC ;
loop init_pgtbl ;
;
; Now that all data structures are in place, allocate stack space
; and record the first free physical location
;
add edi,STACK_SIZE ;
add ebx,STACK_SIZE ;
mov esp,ebx ; stack will be ready later, when we
mov [_pPhysFree],edi ; update SS as well
mov [_pLinFree],edi ; same as PhysFree, since linear==physical
mov [_pFree],ebx ;
;
; Before switching to the new GDT and then the new page tables,
; we need to edit the bases and limits of the GDT selectors again
;
; BUGBUG: Should set accurate limits of selectors
;
mov edi,[_dtrGDT].dtr_dwBase
mov eax,PHYS_TEXT ;
sub eax,offset __ResTextStart
mov es:[edi+SEL_TEXT].des_wBase0_15,ax
shr eax,16 ;
mov es:[edi+SEL_TEXT].des_bBase16_23,al
shr eax,8 ;
mov es:[edi+SEL_TEXT].des_bBase24_31,al
mov eax,[_pPhysData] ;
sub eax,offset DATA:__ResDataStart
mov es:[edi+SEL_DATA].des_wBase0_15,ax
shr eax,16 ;
mov es:[edi+SEL_DATA].des_bBase16_23,al
shr eax,8 ;
mov es:[edi+SEL_DATA].des_bBase24_31,al
mov eax,[_pPhysTSS] ;
mov es:[edi+SEL_TSS].des_wBase0_15,ax
shr eax,16 ;
mov es:[edi+SEL_TSS].des_bBase16_23,al
shr eax,8 ;
mov es:[edi+SEL_TSS].des_bBase24_31,al
;
; Now that the TSS selector is initialized, init the TSS segment
;
mov edi,[_pPhysTSS] ;
mov eax,cr3 ;
mov es:[edi].tss_CR3,eax; save current CR3 in new TSS
mov es:[edi].tss_offIOPM,tss_abIOPM
;
; Now copy the resident data up (we only reserved space for it earlier)
;
mov edi,[_pPhysData] ; ES:EDI -> new resident data location
mov esi,offset DATA:__ResDataStart
mov ecx,[_cbPhysData] ;
mov eax,offset DATA:__ResDataEnd
sub eax,offset DATA:__StaticDataEnd
ifdef DEBUG
mov [_cbBSSData],eax ; save size of BSS data (for assertion)
endif
sub ecx,eax ;
rep movsb ; resident static portion of _DATA moved
mov ecx,eax ;
mov al,0 ;
rep stosb ; resident BSS/c_common portion moved, too
mov edx,[_v86Init] ; EDX == initial v86-mode CS:IP
lidt [_dtrIDT] ; new IDT has been activated
lgdt [_dtrGDT] ; new GDT has been activated
;
; Note that since we're running on the scratch code selector CODE_SEL,
; it doesn't matter (yet) that we've changed SEL_TEXT, so CS is still ok.
; Similarly, SEL_FLAT is unchanged. We must now be careful not to
; reference any non-resident data items however, because DS will only
; access resident data items correctly.
;
mov ax,SEL_DATA ;
mov ds,ax ; I'm not sure if I really need to
mov es,ax ; reload all these after reloading GDTR
mov ss,ax ;
assume ds:DATA_SEG,es:DATA_SEG,ss:DATA_SEG
mov eax,cr0 ;
or eax,CR0_PG ; enable paging
mov cr0,eax ; DONE!
; now jump to flush the prefetch and
; load our new, cool 32-bit code selector
jmp far ptr TEXT:TMain32
Init32 endp
public __ResTextStart
__ResTextStart:
extrn _Main:near
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Main32
;
; 32-bit resident code entry point
;
; ENTRY
; EDX == initial v86-mode CS:IP (from _v86Init, @__DataStart)
;
; EXIT
; Never
;
; USES
; All
;
assume cs:CODE_SEG,ds:DATA_SEG,es:DATA_SEG,ss:DATA_SEG
public Main32
Main32 proc far
mov ebx,[_pTSS]
mov word ptr [ebx].tss_SS0,ss
mov [ebx].tss_ESP0,esp
mov ax,SEL_TSS
ltr ax ; set task register
EnableNMI ; insure that NMI is enabled
;
; Create the initial v86-mode ESF frame
;
sub eax,eax
push eax ; v86GS
push eax ; v86FS
push eax ; v86DS
push eax ; v86ES
push 40h ; v86SS
push eax ; v86ESP
push FLAGS_V86 or FLAGS_IOPL3 or FLAGS_IF; Flags
movzx ecx,dx ; ECX == new IP
shr edx,16 ; EDX == new CS
push edx ; CS
push ecx ; EIP
push eax ; iErrCode (dummy)
push IDT_DEBUG ; iTrap (dummy)
push eax ; EAX
push eax ; ECX
push eax ; EDX
push eax ; EBX
push eax ; ESP
push eax ; EBP
push eax ; ESI
push eax ; EDI
push ds ; saveDS
push es ; saveES
sub esp,esf_saveES ; reserve space for the rest
;
; We are now running at physical address PHYS_TEXT, well above the 1Mb
; boundary, and with paging enabled, but interrupts disabled; it is up to
; _Main to enable ints once all *its* data structures are initialized
;
call _Main ; dispatch to C code
mov ebx,[_pmbZero] ; restore master and slave IMRs
mov al,[ebx].rb_SaveMasterIMR
out PIC_MASTER_IMR,al
mov al,[ebx].rb_SaveSlaveIMR
out PIC_SLAVE_IMR,al
add esp,esf_EDI ; throw away DS, ES, and the rest
popa
add esp,isf_EIP ; throw away iTrap and iErrCode
iretd
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
; _Reboot
;
; ENTRY:
; None
;
; EXIT:
; None
;
; USES:
; All
;
public _Reboot
_Reboot label near
extrn _DrainKbd:near
ifdef KBDSCAN3
extrn _WaitKbdInput:near, _WaitKbdOutput:near
call _WaitKbdInput ; wait for ready state
mov al,KEYCMD_SETSCANSET
out KBDPORT_DATA,al ; tell keyboard to enable new scan set
call _WaitKbdOutput ; wait for acknowledgement
in al,KBDPORT_DATA ; get it