vesa2.asm

linux下的任天堂模拟器代码。供大家参考。

;Copyright (C) 1997-2007 ZSNES Team ( zsKnight, _Demo_, pagefault, Nach )
;
;http://www.zsnes.com
;http://sourceforge.net/projects/zsnes
;https://zsnes.bountysource.com
;
;This program is free software; you can redistribute it and/or
;modify it under the terms of the GNU General Public License
;version 2 as published by the Free Software Foundation.
;
;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.



%include "macros.mac"

EXTSYM DosExit,PrintStr,HalfTransB,HalfTransC,Init_2xSaIMMX,ZSNESBase
EXTSYM UnusedBit,HalfTrans,UnusedBitXor,ngrposng,nggposng,ngbposng
EXTSYM videotroub,ExitFromGUI,ErrorPointer,vesa2_x,vesa2_y,vesa2_bits,TripBufAvail,vesa2red10
EXTSYM vesa2_rposng,vesa2_gposng,vesa2_bposng,vesa2_clbitng,vesa2_clbitng2,vesa2_clbitng3
EXTSYM vesa2_clbit,vesa2_usbit,vesa2_rpos,vesa2_rfull,vesa2_rtrcl,vesa2_rtrcla,genfulladdtab
EXTSYM vesa2_gpos,vesa2_gfull,vesa2_gtrcl,vesa2_gtrcla,vesa2_bpos,vesa2_bfull,vesa2_btrcl,vesa2_btrcla

SECTION .data
; add 0214h video mode
anticrash times 10 db 0

ALIGN32
NEWSYM vesa2selec,      dd 0            ; VESA2 Selector Location
NEWSYM vesa3en,         dd 0
NEWSYM VESAAddr,        dd 0

SECTION .bss

SECTION .text

NEWSYM VESA2EXITTODOS
    mov byte[videotroub],1
    cmp byte[ExitFromGUI],0
    je .nogui
    mov [ErrorPointer],edx
    ret
.nogui
    mov ax,0003h
    int 10h
    push edx
    mov edx,.exitfromvesa2
    call PrintStr
    pop edx
    call PrintStr
    mov edx,.return
    call PrintStr

    jmp DosExit

SECTION .data
.exitfromvesa2 db 'Unable to Initialize VESA2 : ',0
.return db 10,13,0
SECTION .text

;*******************************************************
;   Set up Vesa 2
;*******************************************************

NEWSYM InitVesa2
    ;-------------------------------------------------;
     ; First - allocate some bytes in DOS memory for ;
     ; communication with VBE                        ;
    ;-------------------------------------------------;

    mov eax,0100h
    mov ebx,512/16  ; 512 bytes
    int 31h         ; Function 31h,100h - Allocate
                    ; DOS memory (512 bytes)
    jnc .gotmem
    mov edx,.nomemmessage
    jmp VESA2EXITTODOS

.gotmem
    mov fs,dx   ; FS now points to the DOS buffer

    ;--------------------------------------------------;
     ; Now, get information about the video card into ;
     ; a data structure                               ;
    ;--------------------------------------------------;

    mov edi,RMREGS
    mov dword[fs:0],'VBE2'   ; Request VBE 2.0 info
    mov dword[RMREGS.eax],4f00h
    mov [RMREGS.es],ax       ; Real mode segment of DOS buffer
    mov dword[RMREGS.edi],0

    push es
    push ds
    pop es
    mov eax,300h
    mov ebx,10h
    xor ecx,ecx
    int 31h                  ; Simulate real mode interrupt
    pop es

    jnc .int1ok
    mov edx,.noint1message
    jmp VESA2EXITTODOS


.int1ok              ; Real mode int successful!!!
    mov eax,[RMREGS.eax]
    cmp al,4fh       ; Check vbe interrupt went OK
    jz .vbedetected
    mov edx,.novbemessage
    jmp VESA2EXITTODOS

.vbedetected
    cmp dword[fs:0000],'VESA'
    jz .vesadetected  ; Check for presence of vesa
    mov edx,.novesamessage
    jmp VESA2EXITTODOS


.vesadetected
    cmp word[fs:0004],200h
    jae .vesa2detected ; Check we've got VESA 2.0 or greater
    mov edx,.novesa2message
    jmp VESA2EXITTODOS


    ;-----------------------------------------------------;
     ; OK - vesa 2.0 or greater has been detected. Copy  ;
     ; mode information into VESAmodelist                ;
    ;-----------------------------------------------------;

.vesa2detected
    mov dword[vesa3en],0
    cmp word[fs:004],300h
    jb .notvbe3
    mov dword[vesa3en],1
.notvbe3
    mov ax,[fs:12h]             ; Get no. of 64k blocks
    mov [noblocks],ax
    mov ax, 2
    mov bx,[fs:10h]
    int 31h

    jnc .wegottheselector
    mov edx, .oopsnoselector
    jmp VESA2EXITTODOS

.wegottheselector

    mov gs,ax
    xor eax,eax
    mov ebp,VESAmodelist
    mov ecx,512
    mov ax,[fs:0eh]

.loopcopymodes
    mov bx,[gs:eax]
    mov [ebp],bx
    cmp bx,0ffffh
    jz .copiedmodes
    add ebp,2
    add eax,2
    dec ecx
    jz .outofmodelistspace
    jmp .loopcopymodes

.outofmodelistspace
    mov edx,.outofmodelistspacemessage
    jmp VESA2EXITTODOS

    ;----------------------------------------------;
     ; OK - Scan the mode list to find a matching ;
     ; mode for vesa2_x, vesa2_y and vesa2_depth  ;
    ;----------------------------------------------;

.copiedmodes

    mov ebp,VESAmodelist
    xor ecx,ecx

.loopcheckmodes
    mov cx, [ebp]
    cmp cx, 0ffffh
    jnz .notendoflist

    mov edx,.endoflist
    jmp VESA2EXITTODOS

.notendoflist

    mov edi, RMREGS
    mov dword[RMREGS.eax],4f01h
    mov dword[RMREGS.ebx],0
    mov [RMREGS.ecx],ecx
    mov dword[RMREGS.edi],0

    push es
    push ds
    pop es
    mov eax,300h
    mov ebx,10h
    xor ecx,ecx
    int 31h                 ; Simulate real mode interrupt
    pop es
    jnc .modecheckok
    mov edx,.modecheckfail
    jmp VESA2EXITTODOS

.modecheckok
    add ebp,2

    test word[fs:0000h],1b
    jz near .loopcheckmodes     ; If mode is not available

    mov eax,[vesa2_x]
    cmp [fs:12h],ax             ; Check that the height matches
    jnz near .loopcheckmodes
    mov eax,[vesa2_y]
    cmp [fs:14h],ax             ; Check that the width matches
    jnz near .loopcheckmodes
    mov al,[vesa2_bits]
    cmp [fs:19h],al             ; Check bits/pixel for match
    jnz near .loopcheckmodes

    mov byte[TripBufAvail],1
    test word[fs:0000h],400h
    jz .notbuf
    mov byte[TripBufAvail],1
.notbuf
.notvesa3

;        D0 = Window supported
;                0 = Window is not supported
;                1 = Window is supported
;        D1 = Window readable
;                0 = Window is not readable
;                1 = Window is readable
;        D2 = Window writeable
;                0 = Window is not writeable
;                1 = Window is writeable
;        D3-D7 = Reserved

    mov byte[.whichwin],0
    mov al,[fs:2]      ; Get window A attributes
    and al,0100b
    cmp al,0100b
    je .foundwin       ; Mode supported
    mov al,[fs:3]      ; Get window B attributes
    and al,0100b
    cmp al,0100b
    jne .foundwin      ; Mode not supported
    mov byte[.whichwin],1
.foundwin

    ; Success - a match has been found!!

    sub ebp,2
    mov ax,[ebp]
    mov [vesamode],ax  ; Store vesa 2 mode number

    mov ax,[fs:10h]
    mov byte[vesa2red10],0
    mov byte[vesa2_rposng],11
    mov byte[vesa2_gposng],6
    mov byte[vesa2_bposng],0
    mov dword[vesa2_clbitng],1111011111011110b
    mov dword[vesa2_clbitng2],11110111110111101111011111011110b
    mov dword[vesa2_clbitng2+4],11110111110111101111011111011110b
    mov dword[vesa2_clbitng3],0111101111101111b
    mov [bytesperscanline],ax   ; Store bytes per scan line
    cmp byte[fs:20h],10
    jne near .nored10
    mov byte[fs:20h],11
    mov byte[vesa2red10],1
    mov byte[vesa2_rposng],10
    mov byte[vesa2_gposng],5
    mov dword[vesa2_clbitng],0111101111011110b
    mov dword[vesa2_clbitng2],01111011110111100111101111011110b
    mov dword[vesa2_clbitng2+4],01111011110111100111101111011110b
    mov dword[vesa2_clbitng3],0011110111101111b
    mov dword[UnusedBit],     10000000000000001000000000000000b
    mov dword[HalfTrans],     01111011110111100111101111011110b
    mov dword[UnusedBitXor],  01111111111111110111111111111111b
    mov dword[UnusedBit+4],   10000000000000001000000000000000b
    mov dword[HalfTrans+4],   01111011110111100111101111011110b
    mov dword[UnusedBitXor+4],01111111111111110111111111111111b
    mov dword[HalfTransB],    00000100001000010000010000100001b
    mov dword[HalfTransB+4],  00000100001000010000010000100001b
    mov dword[HalfTransC],    01111011110111100111101111011110b
    mov dword[HalfTransC+4],  01111011110111100111101111011110b
    mov dword[ngrposng],10
    mov dword[nggposng],5
    mov dword[ngbposng],0

.nored10
    ; fix up bit lengths
    mov al,16
    sub al,[fs:20h]
    mov ah,[fs:22h]
    sub ah,[fs:20h]
    mov bl,[fs:24h]
    sub bl,[fs:20h]
    mov bh,al
    cmp bh,ah
    jb .scheck1
    mov bh,ah
.scheck1
    cmp bh,bl
    jb .scheck2
    mov bh,bl
.scheck2
    mov byte[fs:19h],5

    mov al,16
    sub al,[fs:22h]
    mov ah,[fs:20h]
    sub ah,[fs:22h]
    mov bl,[fs:24h]
    sub bl,[fs:22h]
    mov bh,al