cw32.asm

开放源码的编译器open watcom 1.6.0版的源代码

@@pl3:  push    es
        mov     ax,KernalZero
        mov     es,ax
        mov     esi,GDTLinear
        add     esi,KernalTS-3
        mov     es:b[esi+5],DescPresent+DescPL3+Desc386Tss
        pop     es
;
;Setup initial segment variables.
;
        push    ds
        mov     ax,MainDS
        mov     ds,ax
        assume ds:_cwMain
        or      w[SystemFlags],32768    ;Flags us in protected mode.
        mov     RealSegment,KernalZero
        mov     PspSegment,MainPSP
        mov     EnvSegment,MainENV
        mov     CodeSegment,MainCS
        mov     DataSegment,MainDS
        mov     StackSegment,MainSS
        assume ds:_cwRaw
        pop     ds
;
;Make sure A20 is enabled.
;
        push    ds
        mov     ax,InitDS
        mov     ds,ax
        assume ds:_cwInit
        mov     IErrorNumber,7
        assume ds:_cwRaw
        pop     ds
        mov     ax,1
        push    cs
        push    offset @@1
        push    KernalCS
        push    offset A20Handler
        retf
@@1:    jnz     InitError
;
;Now get extended memory sorted out, move the page tables into extended memory
;for a start.
;
        push    ds
        mov     ax,InitDS
        mov     ds,ax
        assume ds:_cwInit
        mov     IErrorNumber,5
        assume ds:_cwRaw
        pop     ds
        mov     ax,KernalZero
        mov     es,ax
;
;Allocate 2nd page table so we can map extended memory.
;
        call    d[fPhysicalGetPage]
        jc      InitError
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.

        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        mov     eax,1
        mov     esi,PageDIRLinear
        mov     es:d[esi+eax*4],edx     ;store this tables address.
        mov     esi,PageAliasLinear     ;get alias table address.
        mov     es:d[esi+eax*4],edx     ;setup in alias table as well.
        call    d[fCR3Flush]
        mov     edi,1024*4096*1023      ;base of page alias's.
        mov     eax,1024*4              ;get the entry number again.
        add     edi,eax
        mov     ecx,4096/4
        xor     eax,eax
        cld
        db 67h
        rep     stosd
        call    d[fCR3Flush]
        mov     LinearEntry,1024
;
;Setup DET page alias.
;
        call    d[fPhysicalGetPage]     ;get page for new page 1st DET.
        jc      InitError
        mov     LinearEntry+8,edx       ;store physical address.
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        mov     eax,LinearEntry ;get the entry number again.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        mov     edi,LinearEntry
        shl     edi,12
        mov     ecx,4096/4
        xor     eax,eax
        cld
        db 67h
        rep     stosd           ;clear it.
        mov     eax,LinearEntry
        shl     eax,12          ;get linear address.
        mov     PageDETLinear,eax
        mov     eax,1022
        mov     esi,PageDIRLinear
        mov     edx,LinearEntry+8       ;get physical address again.
        or      edx,111b
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        mov     esi,PageALIASLinear
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        call    d[fCR3Flush]
        inc     LinearEntry
;
;Setup DET page 1st.
;
        call    d[fPhysicalGetPage]     ;get page for new page 1st.
        jc      InitError
        mov     LinearEntry+8,edx       ;store physical address.
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     eax,LinearEntry ;get the entry number again.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        mov     edi,LinearEntry
        shl     edi,12
        mov     ecx,4096/4
        mov     eax,MEM_FILL
        cld
        db 67h
        rep     stosd           ;copy old to new.
        mov     esi,PageDETLinear
        mov     eax,0
        mov     edx,LinearEntry+8       ;get physical address again.
        or      edx,111b
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        call    d[fCR3Flush]
        inc     LinearEntry
;
;Allocate 2nd page DET
;
        call    d[fPhysicalGetPage]     ;get page for new page 1st.
        jc      InitError
        mov     LinearEntry+8,edx       ;store physical address.
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     eax,LinearEntry ;get the entry number again.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        mov     edi,LinearEntry
        shl     edi,12
        mov     ecx,4096/4
        mov     eax,MEM_FILL
        cld
        db 67h
        rep     stosd           ;copy old to new.
        mov     esi,PageDETLinear
        mov     eax,1
        mov     edx,LinearEntry+8       ;get physical address again.
        or      edx,111b
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        call    d[fCR3Flush]
        inc     LinearEntry
;
;Move page alias into extended memory.
;
        call    d[fPhysicalGetPage]     ;get page for new page 1st.
        jc      InitError
        mov     LinearEntry+8,edx       ;store physical address.
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        mov     eax,LinearEntry ;get the entry number again.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        push    ds
        mov     esi,PageAliasLinear
        mov     edi,LinearEntry
        shl     edi,12
        mov     ecx,4096/4
        push    es
        pop     ds
        cld
        db 67h
        rep     movsd           ;copy old to new.
        pop     ds
        mov     eax,PageALIASLinear
        mov     PageALIASLinear+4,eax
        mov     eax,LinearEntry
        shl     eax,12          ;get linear address.
        mov     PageALIASLinear,eax
        mov     esi,PageDIRLinear
        mov     eax,1023
        mov     edx,LinearEntry+8       ;get physical address again.
        or      edx,111b
        mov     ecx,es:[esi+eax*4]      ;get origional value.
        mov     PageALIASLinear+8,ecx
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        mov     esi,PageALIASLinear
        mov     eax,1023
        mov     edx,LinearEntry+8       ;get physical address again.
        or      edx,111b
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        call    d[fCR3Flush]
        inc     LinearEntry

; MED 09/19/96
COMMENT !
;
;Move page 1st into extended memory.
;
        call    d[fPhysicalGetPage]     ;get page for new page 1st.
        jc      InitError
        mov     LinearEntry+8,edx       ;store physical address.
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        ;
        ;Map it into general linear address space.
        ;
        mov     eax,LinearEntry ;get the entry number again.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        ;
        ;Copy table to new memory.
        ;
        push    ds
        mov     esi,Page1stLinear
        mov     edi,LinearEntry
        shl     edi,12
        mov     ecx,4096/4
        push    es
        pop     ds
        cld
        db 67h
        rep     movsd           ;copy old to new.
        pop     ds
        ;
        ;Make variables point to new memory.
        ;
        mov     eax,Page1stLinear
        mov     Page1stLinear+4,eax     ;store old address.
        mov     eax,LinearEntry
        shl     eax,12          ;get linear address.
        mov     Page1stLinear,eax       ;set new linear address.
        ;
        ;Set new address in page dir.
        ;
        mov     edx,LinearEntry+8       ;get physical address again.
        or      edx,111b
        ;
        mov     esi,PageDIRLinear
        mov     eax,0
        mov     ecx,es:[esi+eax*4]      ;get origional value.
        mov     Page1stLinear+8,ecx
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        call    d[fCR3Flush]
        ;
        ;Set new address in page dir alias.
        ;
        mov     esi,PageALIASLinear
        mov     eax,0
        mov     es:[esi+eax*4],edx      ;put new page into the map.
        call    d[fCR3Flush]
        inc     LinearEntry
END COMMENT !

;
;Move page dir into extended memory.
;
        call    d[fPhysicalGetPage]     ;get page for new page DIR.
        jc      InitError
        mov     LinearEntry+8,edx       ;store physical address.
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        ;
        ;Map it into normal linear address space.
        ;
        mov     eax,LinearEntry ;get the entry number again.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        ;
        ;Copy table to new memory.
        ;
        push    ds
        mov     esi,PageDIRLinear
        mov     edi,LinearEntry
        shl     edi,12
        mov     ecx,4096/4
        push    es
        pop     ds
        cld
        db 67h
        rep     movsd           ;copy old to new.
        pop     ds
        ;
        ;Make variables point to new memory.
        ;
        mov     eax,PageDirLinear
        mov     PageDIRLinear+4,eax     ;store old value.
        mov     eax,LinearEntry
        shl     eax,12          ;get linear address.
        mov     PageDIRLinear,eax       ;set new value.
        mov     eax,VCPI_CR3
        mov     PageDIRLinear+8,eax     ;store old physical address.
        mov     eax,LinearEntry+8
        mov     VCPI_CR3,eax            ;set new physical address.
        movzx   edi,KernalTSSReal
        shl     edi,4
        mov     es:[edi].tCR3,eax       ;set CR3 in TSS as well.
        call    d[fCR3Flush]
        inc     LinearEntry
;
;Setup IDT.
;
        call    d[fPhysicalGetPage]     ;get page for new page DIR.
        jc      InitError
        mov     LinearEntry+8,edx       ;store physical address.
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        mov     eax,LinearEntry ;get the entry number again.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        mov     eax,LinearEntry
        shl     eax,12
        mov     d[IDTVal+2],eax
        mov     w[IDTVal],0+(256*8)-1
        ;
        mov     bp,256          ;number of vectors.
        mov     ecx,offset InterruptHandler ;code address.
        mov     esi,DpmiEmuCS0  ;gate to use.
        mov     al,0
        mov     ah,DescPresent+DescPL3+Desc386Int
        mov     edi,d[IDTVal+2]
@@3:    call    MakeDesc2
        add     edi,8           ;next table address.
        add     ecx,8           ;/
        dec     bp
        jnz     @@3
        inc     LinearEntry
        ;
        ;Re-load IDT value.
        ;
        push    es
        mov     edi,offset MemIntBuffer
        push    ds
        pop     es
        mov     Real_CS[edi],_cwInit
        mov     Real_IP[edi],offset IDTFlush
        mov     Real_SS[edi],0
        mov     Real_SP[edi],0
        call    d[fRawSimulateFCALL]
        pop     es
;
;Get extended memory for DPMI emulator.
;
        push    ds
        mov     ax,InitDS
        mov     ds,ax
        assume ds:_cwInit
        mov     IErrorNumber,5
        assume ds:_cwRaw
        pop     ds
        ;
        mov     ebp,offset cwDPMIEMUEnd-cwDPMIEMUStart
        add     ebp,4095
        shr     ebp,12          ;Get number of pages needed.
        mov     eax,LinearEntry
        shl     eax,12
        mov     LinearEntry+4,eax       ;Store start address.
@@2:    call    d[fPhysicalGetPage]     ;try to allocate a page.
        jc      InitError
        and     ecx,1           ;put user bits in useful place.
        shl     ecx,10
        and     edx,not 4095            ;lose user bits.
        or      edx,111b                ;present+user+write.
        or      edx,ecx         ;set use flags.
        mov     eax,LinearEntry ;get the entry number again.
        mov     esi,1024*4096*1023      ;base of page alias's.
        mov     es:d[esi+eax*4],edx     ;set physical address.
        call    d[fCR3Flush]
        inc     LinearEntry             ;update pointer.
        dec     ebp
        jnz     @@2
;
;Copy DPMI emulator code into extended memory we just allocated.
;
        mov     edi,LinearEntry+4       ;Get the destination.
        mov     si,_cwDPMIEMU
        movzx   esi,si
        shl     esi,4           ;Point to the source.
        mov     ecx,offset cwDPMIEMUEnd-cwDPMIEMUStart
        shr     ecx,2
        push    ds
        push    es
        pop     ds
        cld
        db 67h
        rep     movsd           ;Copy it up their.
        pop     ds
;
;Setup DPMI emulator selectors.
;
        push    es
        mov     ax,GDTData
        mov     es,ax
        mov     esi,LinearEntry+4
        mov     ecx,offset cwDPMIEMUEnd-cwDPMIEMUStart
        mov     al,1 shl 6
        mov     ah,DescPresent+DescPL3+DescMemory+DescERCode
        mov     di,DpmiEmuCS
        call    MakeDesc
        mov     esi,LinearEntry+4
        mov     ecx,offset cwDPMIEMUEnd-cwDPMIEMUStart
        mov     al,1 shl 6
        mov     ah,DescPresent+DescPL0+DescMemory+DescERCode
        mov     di,DpmiEmuCS0
        call    MakeDesc
        mov     esi,LinearEntry+4