;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. %macro Mode7Calculate 0 ; mode 7, ax = curyposition, dx = curxposition (left side) ; draw center map coordinates at (X0-bg1scrolx,Y0-bg1scroly) on screen ; center map coordinates = (X0,Y0) ; 1.) cx=X0-bg1scrolx, cy =Y0-ax mov bx,[mode7X0] and bx,0001111111111111b ; 13 -> 16 bit signed value test bx,0001000000000000b jz .nonega or bx,1110000000000000b .nonega mov [.cxloc],bx mov bx,dx and bx,0001111111111111b ; 13 -> 16 bit signed value test bx,0001000000000000b jz .nonegb or bx,1110000000000000b .nonegb sub [.cxloc],bx mov bx,ax and bx,0001111111111111b ; 13 -> 16 bit signed value test bx,0001000000000000b jz .nonegc or bx,1110000000000000b .nonegc mov [.cyloc],bx mov bx,[mode7Y0] and bx,0001111111111111b ; 13 -> 16 bit signed value test bx,0001000000000000b jz .nonegd or bx,1110000000000000b .nonegd sub word[.cyloc],bx ; 2.) Find position at scaled y, centered x at SCX=X0-(cy*C),SCY=Y0-(cy*D) movsx eax,word[mode7B] movsx ebx,word[.cyloc] imul eax,ebx mov [.mode7xpos],eax mov bx,word[mode7X0] add [.mode7xpos+1],bx movsx ebx,word[.cyloc] movsx eax,word[mode7D] imul eax,ebx mov [.mode7ypos],eax mov bx,word[mode7Y0] add [.mode7ypos+1],bx ; 3.) Find left scaled location : SCX=SCX-(cx*A),SCY=SCY-(cx*B) movsx ebx,word[.cxloc] movsx eax,word[mode7A] mov [.mode7xadder],eax imul eax,ebx neg eax add [.mode7xpos],eax movsx eax,word[mode7C] movsx ebx,word[.cxloc] neg eax mov [.mode7yadder],eax imul eax,ebx add [.mode7ypos],eax test byte[mode7set],1 jz .nohflip mov eax,[.mode7xadder] shl eax,8 add [.mode7xpos],eax neg dword[.mode7xadder] mov eax,[.mode7yadder] shl eax,8 sub [.mode7ypos],eax neg dword[.mode7yadder] .nohflip %endmacro %macro Mode7Process 3 mov dword[.temp],256 test byte[mode7set],80h jnz near %%norep2 mov eax,[.mode7xpos] and eax,7FFh mov [.mode7xrpos],eax mov eax,[.mode7ypos] and eax,7FFh mov [.mode7yrpos],eax ; get tile data offset into edi mov ebx,[.mode7ypos+1] mov eax,[.mode7xpos+1] shl ebx,5 shr eax,3 and ebx,07FF8h shl al,1 mov bl,al mov edi,[vram] xor ecx,ecx mov [.mode7ptr],ebx mov cl,[edi+ebx] shl ecx,7 add edi,ecx mov eax,[.mode7xrpos] mov ebx,[.mode7ptr] jmp %%nextval ALIGN16 %%nextval test ah,08h jnz near %%rposoffx %%nextposx test byte[.mode7yrpos+1],08h jnz near %%rposoffy %%nextposy mov ch,ah mov edx,[.mode7yadder] mov cl,byte[.mode7yrpos+1] sub dword[.mode7yrpos],edx xor edx,edx add eax,[.mode7xadder] mov dl,[mode7tab+ecx] mov dl,[edi+edx] %1 dec dword[.temp] jnz near %%nextval jmp %%finishmode7 %%rposoffx add bl,[.mode7xinc] xor ecx,ecx mov cl,[vrama+ebx] shl ecx,7 sub eax,[.mode7xadd2] lea edi,[ecx+vrama] jmp %%nextposx %%rposoffy sub bh,[.mode7yinc] and ebx,07FFFh xor ecx,ecx mov cl,[vrama+ebx] mov edx,[.mode7yadd2] shl ecx,7 add dword[.mode7yrpos],edx lea edi,[ecx+vrama] jmp %%nextposy %%finishmode7 xor eax,eax mov dh,byte[curmosaicsz] cmp dh,1 jne near %2 ret ;********************************************************** ; Mode 7, no repetition mode ;********************************************************** %%norep2 test byte[mode7set],40h jnz %%tilerep2 jmp %%nextvalb2 ALIGN16 %%nextvalb2 cmp byte[.mode7ypos+2],3 ja %%offscr2 cmp byte[.mode7xpos+2],3 jbe near %%offscr3 %%offscr2 mov eax,[.mode7xadder] mov ebx,[.mode7yadder] add [.mode7xpos],eax sub [.mode7ypos],ebx add esi,%3 dec dword[.temp] jnz near %%nextvalb2 jmp %%finishmode7 %%tilerep2 %%nextvalb3 cmp byte[.mode7ypos+2],3 ja %%offscr2b cmp byte[.mode7xpos+2],3 jbe near %%offscr3 %%offscr2b mov ch,[.mode7xpos+1] mov eax,[.mode7xadder] mov cl,[.mode7ypos+1] mov ebx,[.mode7yadder] mov dl,[mode7tab+ecx] add [.mode7xpos],eax mov dl,[vrama+edx] sub [.mode7ypos],ebx %1 dec dword[.temp] jnz near %%nextvalb3 jmp %%finishmode7 %%offscr3 mov eax,[.mode7xpos] and eax,7FFh mov [.mode7xrpos],eax mov eax,[.mode7ypos] and eax,7FFh mov [.mode7yrpos],eax ; get tile data offset into edi mov ebx,[.mode7ypos+1] mov eax,[.mode7xpos+1] shl ebx,5 shr eax,3 and ebx,07FF8h shl al,1 mov bl,al mov edi,[vram] xor ch,ch mov [.mode7ptr],ebx mov cl,[edi+ebx] shl ecx,7 add edi,ecx jmp %%nextvalr ALIGN16 %%nodr2 add esi,%3 dec dword[.temp] jz near %%fin2 %%nextvalr test byte[.mode7xrpos+1],08h jnz near %%rposoffxr %%nextposxr test byte[.mode7yrpos+1],08h jnz near %%rposoffyr %%nextposyr mov cl,[.mode7yrpos+1] mov ch,[.mode7xrpos+1] mov edx,[.mode7xadder] add dword[.mode7xrpos],edx mov edx,[.mode7xadder] sub dword[.mode7yrpos],edx xor edx,edx mov dl,[mode7tab+ecx] mov dl,[edi+edx] %1 dec dword[.temp] jnz near %%nextvalr %%fin2 jmp %%finishmode7 %%rposoffxr mov al,[.mode7xinc] mov edi,[vram] add [.mode7ptr],al mov cl,byte[.mode7xincc] cmp byte[.mode7ptr],cl je %%roff %%roffxretb mov ebx,[.mode7ptr] xor ecx,ecx mov cl,[edi+ebx] mov eax,[.mode7xadd2] shl ecx,7 sub [.mode7xrpos],eax add edi,ecx jmp %%nextposxr %%rposoffyr mov al,[.mode7yinc] mov edi,[vram] sub [.mode7ptr+1],al js %%roff %%roffyretb mov ebx,[.mode7ptr] xor ecx,ecx mov cl,[edi+ebx] mov eax,[.mode7yadd2] shl ecx,7 add [.mode7yrpos],eax add edi,ecx jmp %%nextposyr %%roff test byte[mode7set],40h jnz %%tilerep3 jmp %%finishmode7 %%tilerep3 and byte[.mode7yrpos+1],07h and byte[.mode7xrpos+1],07h mov cl,[.mode7yrpos+1] mov eax,[.mode7xadder] mov ch,[.mode7xrpos+1] add [.mode7xrpos],eax mov dl,[mode7tab+ecx] mov eax,[.mode7yadder] mov dl,[vrama+edx] sub [.mode7yrpos],eax %1 dec dword[.temp] jnz near %%tilerep3 jmp %%finishmode7 %endmacro