www.pudn.com > zsnes117b-src.zip > sw.asm

;Copyright (C) 1997-2001 ZSNES Team ( zsknight@zsnes.com / _demo_@zsnes.com ) 
; 
;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. 
 
%include "macros.mac" 
 
EXTSYM SidewinderFix 
 
 
 
 
 
 
%macro ParityCheckSW 1 
   mov ecx,ebx 
   xor cl,ch 
   jpe %%ParChkSW 
   mov [%1],ebx 
   %%ParChkSW: 
%endmacro 
 
section .data 
gDump times 256 db 0 
bDump times 128 db 0 
NEWSYM _SW1, dd 0 
NEWSYM _SW2, dd 0 
NEWSYM _SW3, dd 0 
NEWSYM _SW4, dd 0 
NEWSYM _SWCount, dd 0 
 
section .text 
NEWSYM _readSideWinder 
   pushad 
 
   mov ecx,200 
   mov ebx,gDump 
 
   cli 
   cmp byte[SidewinderFix],0 
   je .write 
   out dx,al 
.write 
GetSWDataLoop: 
   cmp byte[SidewinderFix],0 
   jne .nowrite 
   out dx,al 
.nowrite 
   nop 
   nop 
   nop 
   nop 
   nop 
   nop 
   in al,dx 
   mov [ebx],al 
   inc ebx 
   dec ecx 
   jnz GetSWDataLoop 
   sti 
 
   xor ebx,ebx 
   xor ecx,ecx 
   xor edi,edi 
   mov esi,1 
 
FindCycle: 
   mov al,[gDump+edi] 
   inc edi 
   cmp edi,200 
   je SMWError 
   test al,00010000b 
   jnz WMFCS1 
   xor ecx,ecx 
   jmp FindCycle 
WMFCS1: 
   inc ecx 
   cmp ecx,15 
   jne FindCycle 
 
   xor ebp,ebp 
 
FindStrobeLow: 
   mov al,[gDump+edi] 
   inc edi 
   cmp edi,200 
   je SMWError 
   test al,00010000b 
   jnz FindStrobeLow 
   xor ecx,ecx 
 
FindStrobeHigh: 
   inc ecx 
   cmp ecx,15 
   je SWModeCheck 
   mov al,[gDump+edi] 
   inc edi 
   cmp edi,200 
   je SMWError 
   test al,00010000b 
   jz FindStrobeHigh 
 
   mov [bDump+ebp],al 
   inc ebp 
   jmp FindStrobeLow 
 
SMWDone: 
   popad 
   mov eax,0 
   ret 
 
SMWError: 
   popad 
   mov eax,1 
   ret 
 
SWModeCheck: 
   cmp ebp,5 
   je near ModeB1 
   cmp ebp,15 
   je near ModeA1 
   cmp ebp,10 
   je near ModeB2 
   cmp ebp,30 
   je near ModeA2 
   cmp ebp,45 
   je near ModeA3 
   cmp ebp,20 
   je near ModeB4 
   cmp ebp,60 
   je near ModeA4 
   jmp short SMWError 
 
ModeA1: 
   cmp dword [_SWCount],3 
   je near ModeB3 
   xor ebp,ebp 
   call DoModeA 
   ParityCheckSW _SW1 
   jmp SMWDone 
 
ModeA4: 
   mov ebp,45 
   call DoModeA 
   ParityCheckSW _SW4 
ModeA3: 
   mov ebp,30 
   call DoModeA 
   ParityCheckSW _SW3 
ModeA2: 
   mov ebp,15 
   call DoModeA 
   ParityCheckSW _SW2 
   xor ebp,ebp 
   call DoModeA 
   ParityCheckSW _SW1 
   jmp SMWDone 
 
ModeB4: 
   mov ebp,15 
   call DoModeB 
   ParityCheckSW _SW4 
ModeB3: 
   mov ebp,10 
   call DoModeB 
   ParityCheckSW _SW3 
ModeB2: 
   mov ebp,5 
   call DoModeB 
   ParityCheckSW _SW2 
ModeB1: 
   xor ebp,ebp 
   call DoModeB 
   ParityCheckSW _SW1 
   jmp SMWDone 
 
DoModeB: 
   xor ebx,ebx 
   mov eax,2 
   mov ecx,5 
   add ebp,bDump 
ModeBLoop: 
   test byte [ebp],00100000b 
   jnz $+4 
   or ebx,eax 
   shl eax,1 
   test byte [ebp],01000000b 
   jnz $+4 
   or ebx,eax 
   shl eax,1 
   test byte [ebp],10000000b 
   jnz $+4 
   or ebx,eax 
   shl eax,1 
   inc ebp 
   dec ecx 
   jnz ModeBLoop 
   ret 
 
DoModeA: 
   xor ebx,ebx 
   mov eax,2 
   mov ecx,15 
   add ebp,bDump 
ModeALoop: 
   test byte [ebp],00100000b 
   jnz $+4 
   or ebx,eax 
   shl eax,1 
   inc ebp 
   dec ecx 
   jnz ModeALoop 
   ret