c4emu.cpp

SFC游戏模拟器 snes9x 1.43 的原代码

/*******************************************************************************
  Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 
  (c) Copyright 1996 - 2002 Gary Henderson ([e-mail]) and
                            Jerremy Koot ([e-mail])

  (c) Copyright 2001 - 2004 John Weidman ([e-mail])

  (c) Copyright 2002 - 2004 Brad Jorsch ([e-mail]),
                            funkyass ([e-mail]),
                            Joel Yliluoma (http://iki.fi/bisqwit/)
                            Kris Bleakley ([e-mail]),
                            Matthew Kendora,
                            Nach ([e-mail]),
                            Peter Bortas ([e-mail]) and
                            zones ([e-mail])

  C4 x86 assembler and some C emulation code
  (c) Copyright 2000 - 2003 zsKnight ([e-mail]),
                            _Demo_ ([e-mail]), and Nach

  C4 C++ code
  (c) Copyright 2003 Brad Jorsch

  DSP-1 emulator code
  (c) Copyright 1998 - 2004 Ivar ([e-mail]), _Demo_, Gary Henderson,
                            John Weidman, neviksti ([e-mail]),
                            Kris Bleakley, Andreas Naive

  DSP-2 emulator code
  (c) Copyright 2003 Kris Bleakley, John Weidman, neviksti, Matthew Kendora, and
                     Lord Nightmare ([e-mail]

  OBC1 emulator code
  (c) Copyright 2001 - 2004 zsKnight, pagefault ([e-mail]) and
                            Kris Bleakley
  Ported from x86 assembler to C by sanmaiwashi

  SPC7110 and RTC C++ emulator code
  (c) Copyright 2002 Matthew Kendora with research by
                     zsKnight, John Weidman, and Dark Force

  S-DD1 C emulator code
  (c) Copyright 2003 Brad Jorsch with research by
                     Andreas Naive and John Weidman
 
  S-RTC C emulator code
  (c) Copyright 2001 John Weidman
  
  ST010 C++ emulator code
  (c) Copyright 2003 Feather, Kris Bleakley, John Weidman and Matthew Kendora

  Super FX x86 assembler emulator code 
  (c) Copyright 1998 - 2003 zsKnight, _Demo_, and pagefault 

  Super FX C emulator code 
  (c) Copyright 1997 - 1999 Ivar, Gary Henderson and John Weidman


  SH assembler code partly based on x86 assembler code
  (c) Copyright 2002 - 2004 Marcus Comstedt ([e-mail]) 

 
  Specific ports contains the works of other authors. See headers in
  individual files.
 
  Snes9x homepage: http://www.snes9x.com
 
  Permission to use, copy, modify and distribute Snes9x in both binary and
  source form, for non-commercial purposes, is hereby granted without fee,
  providing that this license information and copyright notice appear with
  all copies and any derived work.
 
  This software is provided 'as-is', without any express or implied
  warranty. In no event shall the authors be held liable for any damages
  arising from the use of this software.
 
  Snes9x is freeware for PERSONAL USE only. Commercial users should
  seek permission of the copyright holders first. Commercial use includes
  charging money for Snes9x or software derived from Snes9x.
 
  The copyright holders request that bug fixes and improvements to the code
  should be forwarded to them so everyone can benefit from the modifications
  in future versions.
 
  Super NES and Super Nintendo Entertainment System are trademarks of
  Nintendo Co., Limited and its subsidiary companies.
*******************************************************************************/
#ifdef HAVE_CONFIG_H
	#include <config.h>
#endif
#include <math.h>
#include "snes9x.h"
#include "sar.h"
#include "memmap.h"
#include "ppu.h"
#include "c4.h"

void S9xInitC4 ()
{
    // Stupid zsnes code, we can't do the logical thing without breaking
    // savestates
//    Memory.C4RAM = &Memory.FillRAM [0x6000];
    memset(Memory.C4RAM, 0, 0x2000);
}

uint8 S9xGetC4 (uint16 Address)
{
#ifdef DEBUGGER
    if(Settings.BGLayering) printf("%02x from %04x\n", Memory.C4RAM[Address-0x6000], Address);
#endif
    return (Memory.C4RAM [Address-0x6000]);
}

static uint8 C4TestPattern [12 * 4] =
{
    0x00, 0x00, 0x00, 0xff,
    0xff, 0xff, 0x00, 0xff,
    0x00, 0x00, 0x00, 0xff,
    0xff, 0xff, 0x00, 0x00,
    0xff, 0xff, 0x00, 0x00,
    0x80, 0xff, 0xff, 0x7f,
    0x00, 0x80, 0x00, 0xff,
    0x7f, 0x00, 0xff, 0x7f,
    0xff, 0x7f, 0xff, 0xff,
    0x00, 0x00, 0x01, 0xff,
    0xff, 0xfe, 0x00, 0x01,
    0x00, 0xff, 0xfe, 0x00
};


static void C4ConvOAM(void){
    uint8 *OAMptr=Memory.C4RAM+(Memory.C4RAM[0x626]<<2);
    for(uint8 *i=Memory.C4RAM+0x1fd; i>OAMptr; i-=4){
        // Clear OAM-to-be
        *i=0xe0;
    }

    uint16 globalX, globalY;
    uint8 *OAMptr2;
    int16 SprX, SprY;
    uint8 SprName, SprAttr;
    uint8 SprCount;
    
    globalX=READ_WORD(Memory.C4RAM+0x0621);
    globalY=READ_WORD(Memory.C4RAM+0x0623);
    OAMptr2=Memory.C4RAM+0x200+(Memory.C4RAM[0x626]>>2);

#ifdef DEBUGGER
    if(Memory.C4RAM[0x625]!=0) printf("$6625=%02x, expected 00\n", Memory.C4RAM[0x625]);
    if((Memory.C4RAM[0x626]>>2)!=Memory.C4RAM[0x629]) printf("$6629=%02x, expected %02x\n", Memory.C4RAM[0x629], (Memory.C4RAM[0x626]>>2));
    if(((uint16)Memory.C4RAM[0x626]<<2)!=READ_WORD(Memory.C4RAM+0x627)) printf("$6627=%04x, expected %04x\n", READ_WORD(Memory.C4RAM+0x627), ((uint16)Memory.C4RAM[0x626]<<2));
#endif

    if(Memory.C4RAM[0x0620]!=0){
        SprCount=128-Memory.C4RAM[0x626];
        uint8 offset=(Memory.C4RAM[0x626]&3)*2;
        for(int prio=0x30; prio>=0; prio-=0x10){
            uint8 *srcptr=Memory.C4RAM+0x220;
            for(int i=Memory.C4RAM[0x0620]; i>0 && SprCount>0; i--, srcptr+=16){
                if((srcptr[4]&0x30)!=prio) continue;
                SprX=READ_WORD(srcptr)-globalX;
                SprY=READ_WORD(srcptr+2)-globalY;
                SprName=srcptr[5];
                SprAttr=srcptr[4] | srcptr[0x06]; // XXX: mask bits?

                uint8 *sprptr=S9xGetMemPointer(READ_3WORD(srcptr+7));
                if(*sprptr!=0){
                    int16 X, Y;
                    for(int SprCnt=*sprptr++; SprCnt>0 && SprCount>0; SprCnt--, sprptr+=4){
                        X=(int8)sprptr[1];
                        if(SprAttr&0x40){ // flip X
                            X=-X-((sprptr[0]&0x20)?16:8);
                        }
                        X+=SprX;
                        if(X>=-16 && X<=272){
                            Y=(int8)sprptr[2];
                            if(SprAttr&0x80){
                                Y=-Y-((sprptr[0]&0x20)?16:8);
                            }
                            Y+=SprY;
                            if(Y>=-16 && Y<=224){
                                OAMptr[0]=X&0xff;
                                OAMptr[1]=(uint8)Y;
                                OAMptr[2]=SprName+sprptr[3];
                                OAMptr[3]=SprAttr^(sprptr[0]&0xc0); // XXX: Carry from SprName addition?
                                *OAMptr2 &= ~(3<<offset);
                                if(X&0x100) *OAMptr2 |= 1<<offset;
                                if(sprptr[0]&0x20) *OAMptr2 |= 2<<offset;
                                OAMptr+=4;
                                SprCount--;
                                offset=(offset+2)&6;
                                if(offset==0) OAMptr2++;
                            }
                        }
                    }
                } else if(SprCount>0){
                    OAMptr[0]=(uint8)SprX;
                    OAMptr[1]=(uint8)SprY;
                    OAMptr[2]=SprName;
                    OAMptr[3]=SprAttr;
                    *OAMptr2 &= ~(3<<offset);
                    if(SprX&0x100) *OAMptr2 |= 3<<offset;
                    else *OAMptr2 |= 2<<offset;
                    OAMptr+=4;
                    SprCount--;
                    offset=(offset+2)&6;
                    if(offset==0) OAMptr2++;
                }
            }
        }
    }
    // XXX: Copy to OAM? I doubt it.
}

static void C4DoScaleRotate(int row_padding){
    int16 A, B, C, D;

    // Calculate matrix
    int32 XScale=READ_WORD(Memory.C4RAM+0x1f8f);
    if(XScale&0x8000) XScale=0x7fff;
    int32 YScale=READ_WORD(Memory.C4RAM+0x1f92);
    if(YScale&0x8000) YScale=0x7fff;

    if(READ_WORD(Memory.C4RAM+0x1f80)==0)
	{ // no rotation
        // XXX: only do this for C and D?
        // XXX: and then only when YScale is 0x1000?
        A=(int16)XScale;
		B=0;
        C=0;
		D=(int16)YScale;
    }
	else if(READ_WORD(Memory.C4RAM+0x1f80)==128){ // 90 degree rotation
        // XXX: Really do this?
        A=0;
		B=(int16)(-YScale);
        C=(int16)XScale;
		D=0;
    } else if(READ_WORD(Memory.C4RAM+0x1f80)==256){ // 180 degree rotation
        // XXX: Really do this?
        A=(int16)(-XScale);
		B=0;
        C=0;
		D=(int16)(-YScale);
    } else if(READ_WORD(Memory.C4RAM+0x1f80)==384){ // 270 degree rotation
        // XXX: Really do this?
        A=0;
		B=(int16)YScale;
        C=(int16)(-XScale);
		D=0;
    } else {
        A=(int16)SAR(C4CosTable[READ_WORD(Memory.C4RAM+0x1f80)&0x1ff]*XScale, 15);
        B=(int16)(-SAR(C4SinTable[READ_WORD(Memory.C4RAM+0x1f80)&0x1ff]*YScale, 15));
        C=(int16)SAR(C4SinTable[READ_WORD(Memory.C4RAM+0x1f80)&0x1ff]*XScale, 15);
        D=(int16)SAR(C4CosTable[READ_WORD(Memory.C4RAM+0x1f80)&0x1ff]*YScale, 15);
    }

    // Calculate Pixel Resolution
    uint8 w=Memory.C4RAM[0x1f89]&~7;
    uint8 h=Memory.C4RAM[0x1f8c]&~7;

//    printf("%dx%d XScale=%04x YScale=%04x angle=%03x\n", w, h, XScale, YScale, READ_WORD(Memory.C4RAM+0x1f80)&0x1ff);
//    printf("Matrix: [%10g %10g]  [%04x %04x]\n", A/4096.0, B/4096.0, A&0xffff, B&0xffff);
//    printf("        [%10g %10g]  [%04x %04x]\n", C/4096.0, D/4096.0, C&0xffff, D&0xffff);

    // Clear the output RAM
    memset(Memory.C4RAM, 0, (w+row_padding/4)*h/2);

    int32 Cx=(int16)READ_WORD(Memory.C4RAM+0x1f83);
    int32 Cy=(int16)READ_WORD(Memory.C4RAM+0x1f86);

#ifdef DEBUGGER
    if(Memory.C4RAM[0x1f97]!=0) printf("$7f97=%02x, expected 00\n", Memory.C4RAM[0x1f97]);
    if((Cx&~1)!=w/2 || (Cy&~1)!=h/2) printf("Center is not middle of image! (%d, %d) != (%d, %d)\n", Cx, Cy, w/2, h/2);
#endif

    // Calculate start position (i.e. (Ox, Oy) = (0, 0))
    // The low 12 bits are fractional, so (Cx<<12) gives us the Cx we want in
    // the function. We do Cx*A etc normally because the matrix parameters
    // already have the fractional parts.
    int32 LineX=(Cx<<12) - Cx*A - Cx*B;
    int32 LineY=(Cy<<12) - Cy*C - Cy*D;
    
    // Start loop
    uint32 X, Y;
    uint8 byte;
    int outidx=0;
    uint8 bit=0x80;
    for(int y=0; y<h; y++){
        X=LineX;
        Y=LineY;
        for(int x=0; x<w; x++){
            if((X>>12)>=w || (Y>>12)>=h){
                byte=0;
            } else {
                uint32 addr=(Y>>12)*w+(X>>12);
                byte=Memory.C4RAM[0x600+(addr>>1)];
                if(addr&1) byte>>=4;
            }

            // De-bitplanify
            if(byte&1) Memory.C4RAM[outidx]|=bit;
            if(byte&2) Memory.C4RAM[outidx+1]|=bit;
            if(byte&4) Memory.C4RAM[outidx+16]|=bit;
            if(byte&8) Memory.C4RAM[outidx+17]|=bit;

            bit>>=1;
            if(bit==0){
                bit=0x80;
                outidx+=32;
            }
            
            X+=A; // Add 1 to output x => add an A and a C
            Y+=C;
        }
        outidx+=2+row_padding;
        if(outidx&0x10){
            outidx&=~0x10;
        } else {
            outidx-=w*4+row_padding;
        }
        LineX+=B; // Add 1 to output y => add a B and a D
        LineY+=D;
    }
}

static void C4DrawLine(int32 X1, int32 Y1, int16 Z1,
                       int32 X2, int32 Y2, int16 Z2, uint8 Color){
    // Transform coordinates
    C4WFXVal=(short)X1;
    C4WFYVal=(short)Y1;
    C4WFZVal=Z1;
    C4WFScale=Memory.C4RAM[0x1f90];
    C4WFX2Val=Memory.C4RAM[0x1f86];
    C4WFY2Val=Memory.C4RAM[0x1f87];
    C4WFDist=Memory.C4RAM[0x1f88];
    C4TransfWireFrame2();
    X1=(C4WFXVal+48)<<8;
    Y1=(C4WFYVal+48)<<8;