st10proc.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 setaramdata,ST010DoCommand

SECTION .data
NEWSYM SetaCmdEnable,    dd 0     ; Seta ST010/ST011 command enable register. Maybe also status.
SECTION .text

;; TODO - should return ROM for > 8000h
NEWSYM setaaccessbankr8
    mov ebx,[setaramdata]
    and ecx,0fffh
    mov al,[ebx+ecx]
    xor ebx,ebx
    ret

NEWSYM setaaccessbankw8
    test ecx,8000h
    jnz .nosetenablew8  ; ignore ROM writes
    and ecx,0fffh
    mov ebx,[setaramdata]
    mov [ebx+ecx],al
    cmp byte[ebx+021h], 80h
    jnz .nosetenablew8
    pushad
    call ST010DoCommand
    popad
.nosetenablew8
    xor ebx,ebx
    ret

;; We ignore the case where it wraps into ROM reads - should never happen
NEWSYM setaaccessbankr16
    mov ebx,[setaramdata]
    and ecx,0fffh
    mov ax,[ebx+ecx]
    xor ebx,ebx
    ret

NEWSYM setaaccessbankw16
    test ecx,8000h
    jnz .nosetenablew16  ; ignore ROM writes
    cmp ecx,7fffh
    jne .noromw16
    mov [setaramdata+0fffh],al  ; only write ram part in, not rom part
    jmp short .nosetenablew16
.noromw16
    and ecx,0fffh
    mov ebx,[setaramdata]
    cmp ecx,0fffh
    jne .nowrapw16
    mov [ebx+ecx],al
    xchg ah,al
    mov [ebx],al
    jmp short .nosetenablew16
.nowrapw16
    mov [ebx+ecx],ax
    cmp byte[ebx+021h], 80h
    jnz .nosetenablew16
    pushad
    call ST010DoCommand
    popad
.nosetenablew16
    xor ebx,ebx
    ret


NEWSYM setaaccessbankr8a
    xor al,al
    cmp ecx,4000h
    jae .nosetenabler8a
    and ecx, 3
    mov al,[SetaCmdEnable+ecx]
.nosetenabler8a
    xor ebx,ebx
    ret

NEWSYM setaaccessbankw8a
    cmp ecx,4000h
    jae .nosetenablew8a
    and ecx, 03h
    mov [SetaCmdEnable+ecx],al
.nosetenablew8a
    xor ebx,ebx
    ret

NEWSYM setaaccessbankr16a
    xor ax,ax
    cmp ecx,4000h
    jae .nosetenabler16a
    and ecx,3
    mov al,[SetaCmdEnable+ecx]
    xchg ah,al
    inc ecx
    and ecx,3
    mov al,[SetaCmdEnable+ecx]
.nosetenabler16a
    xor ebx,ebx
    ret

NEWSYM setaaccessbankw16a
    cmp ecx,4000h
    jae .nosetenablew16a
    mov ebx,[setaramdata]
    and ecx,3
    mov [ebx+ecx],al
    xchg ah,al
    inc ecx
    and ecx,3
    mov [ebx+ecx],al
.nosetenablew16a
    xor ebx,ebx
    ret