fxinst.h

著名SFC模拟器Snes9x的源代码。

/*
 * Snes9x - Portable Super Nintendo Entertainment System (TM) emulator.
 *
 * (c) Copyright 1996 - 2001 Gary Henderson ([e-mail]) and
 *                           Jerremy Koot ([e-mail])
 *
 * Super FX C emulator code 
 * (c) Copyright 1997 - 1999 Ivar ([e-mail]) and
 *                           Gary Henderson.
 * Super FX assembler emulator code (c) Copyright 1998 zsKnight and _Demo_.
 *
 * DSP1 emulator code (c) Copyright 1998 Ivar, _Demo_ and Gary Henderson.
 * C4 asm and some C emulation code (c) Copyright 2000 zsKnight and _Demo_.
 * C4 C code (c) Copyright 2001 Gary Henderson ([e-mail]).
 *
 * DOS port code contains the works of other authors. See headers in
 * individual files.
 *
 * Snes9x homepage: 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.
 */
#ifndef _FXINST_H_
#define _FXINST_H_ 1

/*
 * FxChip(GSU) register space specification
 * (Register address space 3000->32ff)
 *
 * The 16 generic 16 bit registers:
 * (Some have a special function in special circumstances)
 * 3000 - R0	default source/destination register
 * 3002 - R1	pixel plot X position register
 * 3004 - R2	pixel plot Y position register
 * 3006 - R3
 * 3008 - R4	lower 16 bit result of lmult
 * 300a - R5 
 * 300c - R6	multiplier for fmult and lmult
 * 300e - R7	fixed point texel X position for merge
 * 3010 - R8	fixed point texel Y position for merge
 * 3012 - R9 
 * 3014 - R10 
 * 3016 - R11	return address set by link
 * 3018 - R12	loop counter
 * 301a - R13	loop point address
 * 301c - R14	rom address for getb, getbh, getbl, getbs
 * 301e - R15	program counter 
 *
 * 3020-302f -	unused
 * 
 * Other internal registers
 * 3030 - SFR	status flag register (16bit)
 * 3032 -	unused
 * 3033 - BRAMR Backup RAM register (8bit)
 * 3034 - PBR	program bank register (8bit)
 * 3035 -	unused
 * 3036 - ROMBR	rom bank register (8bit)
 * 3037 - CFGR	control flags register (8bit)
 * 3038 - SCBR	screen base register (8bit)
 * 3039 - CLSR	clock speed register (8bit)
 * 303a - SCMR	screen mode register (8bit)
 * 303b - VCR	version code register (8bit) (read only)
 * 303c - RAMBR	ram bank register (8bit)
 * 303d -	unused
 * 303e - CBR	cache base register (16bit)
 *
 * 3040-30ff -	unused
 *
 * 3100-32ff -	CACHERAM 512 bytes of GSU cache memory
 *
 * SFR status flag register bits:
 *  0   -	
 *  1   Z	Zero flag
 *  2   CY	Carry flag
 *  3   S	Sign flag
 *  4   OV	Overflow flag
 *  5   G	Go flag (set to 1 when the GSU is running)
 *  6   R	Set to 1 when reading ROM using R14 address
 *  7   -	
 *  8   ALT1	Mode set-up flag for the next instruction
 *  9   ALT2	Mode set-up flag for the next instruction
 * 10   IL	Immediate lower 8-bit flag
 * 11   IH	Immediate higher 8-bit flag
 * 12   B	Set to 1 when the WITH instruction is executed
 * 13   -	
 * 14   -	
 * 15   IRQ	Set to 1 when GSU caused an interrupt
 *              Set to 0 when read by 658c16
 *
 * BRAMR = 0, BackupRAM is disabled
 * BRAMR = 1, BackupRAM is enabled
 *
 * CFGR control flags register bits:
 *  0   -	
 *  1   -	
 *  2   -	
 *  3   -	
 *  4   -	
 *  5   MS0	Multiplier speed, 0=standard, 1=high speed
 *  6   -	
 *  7   IRQ	Set to 1 when GSU interrupt request is masked
 *
 * CLSR clock speed register bits:
 *  0   CLSR	clock speed, 0 = 10.7Mhz, 1 = 21.4Mhz
 *
 * SCMR screen mode register bits:
 *  0	MD0	color depth mode bit 0
 *  1	MD1	color depth mode bit 1
 *  2	HT0	screen height bit 1
 *  3	RAN	RAM access control
 *  4	RON	ROM access control
 *  5	HT1	screen height bit 2
 *  6	-	
 *  7	-	
 *
 * RON = 0	SNES CPU has ROM access
 * RON = 1	GSU has ROM access
 *
 * RAN = 0	SNES has game pak RAM access
 * RAN = 1	GSU has game pak RAM access
 *
 * HT1  HT0  Screen height mode
 *  0    0   128 pixels high
 *  0    1   160 pixels high
 *  1    0   192 pixels high
 *  1    1   OBJ mode
 *
 * MD1  MD0  Color depth mode
 *  0    0   4 color mode
 *  0    1   16 color mode
 *  1    0   not used
 *  1    1   256 color mode
 *
 * CBR cache base register bits:
 * 15-4	     Specify base address for data to cache from ROM or RAM
 *  3-0	     Are 0 when address is read
 *
 * Write access to the program counter (301e) from
 * the SNES-CPU will start the GSU, and it will not
 * stop until it reaches a stop instruction.
 *
 */

/* Number of banks in GSU RAM */
#define FX_RAM_BANKS 4

/* Emulate proper R14 ROM access (slower, but safer) */
/* #define FX_DO_ROMBUFFER */

/* Address checking (definately slow) */
/* #define FX_ADDRESS_CHECK */

struct FxRegs_s
{
    /* FxChip registers */
    uint32	avReg[16];		/* 16 Generic registers */
    uint32	vColorReg;		/* Internal color register */
    uint32	vPlotOptionReg;		/* Plot option register */
    uint32	vStatusReg;		/* Status register */
    uint32	vPrgBankReg;		/* Program bank index register */
    uint32	vRomBankReg;		/* Rom bank index register */
    uint32	vRamBankReg;		/* Ram bank index register */
    uint32	vCacheBaseReg;		/* Cache base address register */
    uint32	vCacheFlags;		/* Saying what parts of the cache was written to */
    uint32	vLastRamAdr;		/* Last RAM address accessed */
    uint32 *	pvDreg;			/* Pointer to current destination register */
    uint32 *	pvSreg;			/* Pointer to current source register */
    uint8	vRomBuffer;		/* Current byte read by R14 */
    uint8	vPipe;			/* Instructionset pipe */
    uint32	vPipeAdr;		/* The address of where the pipe was read from */

    /* status register optimization stuff */
    uint32	vSign;			/* v & 0x8000 */
    uint32	vZero;			/* v == 0 */
    uint32	vCarry;			/* a value of 1 or 0 */
    int32	vOverflow;		/* (v >= 0x8000 || v < -0x8000) */
    
    /* Other emulator variables */
    
    int32	vErrorCode;
    uint32	vIllegalAddress;
    
    uint8	bBreakPoint;
    uint32	vBreakPoint;
    uint32	vStepPoint;
    
    uint8 *	pvRegisters;	/* 768 bytes located in the memory at address 0x3000 */
    uint32	nRamBanks;	/* Number of 64kb-banks in FxRam (Don't confuse it with SNES-Ram!!!) */
    uint8 *	pvRam;		/* Pointer to FxRam */
    uint32	nRomBanks;	/* Number of 32kb-banks in Cart-ROM */
    uint8 *     pvRom;		/* Pointer to Cart-ROM */

    uint32	vMode;		/* Color depth/mode */
    uint32	vPrevMode;	/* Previous depth */
    uint8 *	pvScreenBase;
    uint8 *	apvScreen[32];		/* Pointer to each of the 32 screen colums */
    int		x[32];
    uint32	vScreenHeight;		/* 128, 160, 192 or 256 (could be overriden by cmode) */
    uint32	vScreenRealHeight;	/* 128, 160, 192 or 256 */
    uint32	vPrevScreenHeight;
    uint32	vScreenSize;
    void	(*pfPlot)();
    void	(*pfRpix)();
    
    uint8 *	pvRamBank;		/* Pointer to current RAM-bank */
    uint8 *	pvRomBank;		/* Pointer to current ROM-bank */
    uint8 *	pvPrgBank;		/* Pointer to current program ROM-bank */

    uint8 *	apvRamBank[FX_RAM_BANKS];/* Ram bank table (max 256kb) */
    uint8 *	apvRomBank[256];	/* Rom bank table */

    uint8	bCacheActive;
    uint8 *	pvCache;		/* Pointer to the GSU cache */
    uint8 	avCacheBackup[512];	/* Backup of ROM when the cache has replaced it */
    uint32	vCounter;
    uint32	vInstCount;
};

/* GSU registers */
#define GSU_R0 0x000
#define GSU_R1 0x002
#define GSU_R2 0x004
#define GSU_R3 0x006
#define GSU_R4 0x008
#define GSU_R5 0x00a
#define GSU_R6 0x00c
#define GSU_R7 0x00e
#define GSU_R8 0x010
#define GSU_R9 0x012
#define GSU_R10 0x014
#define GSU_R11 0x016
#define GSU_R12 0x018
#define GSU_R13 0x01a
#define GSU_R14 0x01c
#define GSU_R15 0x01e
#define GSU_SFR 0x030
#define GSU_BRAMR 0x033
#define GSU_PBR 0x034
#define GSU_ROMBR 0x036
#define GSU_CFGR 0x037
#define GSU_SCBR 0x038
#define GSU_CLSR 0x039
#define GSU_SCMR 0x03a
#define GSU_VCR 0x03b
#define GSU_RAMBR 0x03c
#define GSU_CBR 0x03e
#define GSU_CACHERAM 0x100

/* SFR flags */
#define FLG_Z (1<<1)
#define FLG_CY (1<<2)
#define FLG_S (1<<3)
#define FLG_OV (1<<4)
#define FLG_G (1<<5)
#define FLG_R (1<<6)
#define FLG_ALT1 (1<<8)
#define FLG_ALT2 (1<<9)
#define FLG_IL (1<<10)
#define FLG_IH (1<<11)
#define FLG_B (1<<12)
#define FLG_IRQ (1<<15)

/* Test flag */
#define TF(a) (GSU.vStatusReg & FLG_##a )
#define CF(a) (GSU.vStatusReg &= ~FLG_##a )
#define SF(a) (GSU.vStatusReg |= FLG_##a )

/* Test and set flag if condition, clear if not */
#define TS(a,b) GSU.vStatusReg = ( (GSU.vStatusReg & (~FLG_##a)) | ( (!!(##b)) * FLG_##a ) )

/* Testing ALT1 & ALT2 bits */
#define ALT0 (!TF(ALT1)&&!TF(ALT2))
#define ALT1 (TF(ALT1)&&!TF(ALT2))
#define ALT2 (!TF(ALT1)&&TF(ALT2))
#define ALT3 (TF(ALT1)&&TF(ALT2))

/* Sign extend from 8/16 bit to 32 bit */
#define SEX16(a) ((int32)((int16)(a)))
#define SEX8(a) ((int32)((int8)(a)))

/* Unsign extend from 8/16 bit to 32 bit */
#define USEX16(a) ((uint32)((uint16)(a)))
#define USEX8(a) ((uint32)((uint8)(a)))

#define SUSEX16(a) ((int32)((uint16)(a)))

/* Set/Clr Sign and Zero flag */
#define TSZ(num) TS(S, (num & 0x8000)); TS(Z, (!USEX16(num)) )

/* Clear flags */
#define CLRFLAGS GSU.vStatusReg &= ~(FLG_ALT1|FLG_ALT2|FLG_B); GSU.pvDreg = GSU.pvSreg = &R0;

/* Read current RAM-Bank */
#define RAM(adr) GSU.pvRamBank[USEX16(adr)]

/* Read current ROM-Bank */
#define ROM(idx) (GSU.pvRomBank[USEX16(idx)])

/* Access the current value in the pipe */
#define PIPE GSU.vPipe

/* Access data in the current program bank */
#define PRGBANK(idx) GSU.pvPrgBank[USEX16(idx)]

/* Update pipe from ROM */
#if 0
#define FETCHPIPE { PIPE = PRGBANK(R15); GSU.vPipeAdr = (GSU.vPrgBankReg<<16) + R15; }
#else
#define FETCHPIPE { PIPE = PRGBANK(R15); }
#endif

/* ABS */
#define ABS(x) ((x)<0?-(x):(x))

/* Access source register */
#define SREG (*GSU.pvSreg)

/* Access destination register */
#define DREG (*GSU.pvDreg)

#ifndef FX_DO_ROMBUFFER

/* Don't read R14 */
#define READR14

/* Don't test and/or read R14 */
#define TESTR14

#else

/* Read R14 */
#define READR14 GSU.vRomBuffer = ROM(R14)

/* Test and/or read R14 */
#define TESTR14 if(GSU.pvDreg == &R14) READR14

#endif

/* Access to registers */
#define R0 GSU.avReg[0]
#define R1 GSU.avReg[1]
#define R2 GSU.avReg[2]
#define R3 GSU.avReg[3]
#define R4 GSU.avReg[4]
#define R5 GSU.avReg[5]
#define R6 GSU.avReg[6]
#define R7 GSU.avReg[7]
#define R8 GSU.avReg[8]
#define R9 GSU.avReg[9]
#define R10 GSU.avReg[10]
#define R11 GSU.avReg[11]
#define R12 GSU.avReg[12]
#define R13 GSU.avReg[13]
#define R14 GSU.avReg[14]
#define R15 GSU.avReg[15]
#define SFR GSU.vStatusReg
#define PBR GSU.vPrgBankReg
#define ROMBR GSU.vRomBankReg
#define RAMBR GSU.vRamBankReg
#define CBR GSU.vCacheBaseReg
#define SCBR USEX8(GSU.pvRegisters[GSU_SCBR])
#define SCMR USEX8(GSU.pvRegisters[GSU_SCMR])
#define COLR GSU.vColorReg
#define POR GSU.vPlotOptionReg
#define BRAMR USEX8(GSU.pvRegisters[GSU_BRAMR])
#define VCR USEX8(GSU.pvRegisters[GSU_VCR])
#define CFGR USEX8(GSU.pvRegisters[GSU_CFGR])
#define CLSR USEX8(GSU.pvRegisters[GSU_CLSR])

/* Execute instruction from the pipe, and fetch next byte to the pipe */
#define FX_STEP { uint32 vOpcode = (uint32)PIPE; FETCHPIPE; \
(*fx_ppfOpcodeTable[ (GSU.vStatusReg & 0x300) | vOpcode ])(); } \

#define FX_FUNCTION_RUN			0
#define FX_FUNCTION_RUN_TO_BREAKPOINT	1
#define FX_FUNCTION_STEP_OVER		2

extern uint32 (**fx_ppfFunctionTable)(uint32);
extern void (**fx_ppfPlotTable)();
extern void (**fx_ppfOpcodeTable)();

extern uint32 (*fx_apfFunctionTable[])(uint32);
extern void (*fx_apfOpcodeTable[])();
extern void (*fx_apfPlotTable[])();
extern uint32 (*fx_a_apfFunctionTable[])(uint32);
extern void (*fx_a_apfOpcodeTable[])();
extern void (*fx_a_apfPlotTable[])();
extern uint32 (*fx_r_apfFunctionTable[])(uint32);
extern void (*fx_r_apfOpcodeTable[])();
extern void (*fx_r_apfPlotTable[])();
extern uint32 (*fx_ar_apfFunctionTable[])(uint32);
extern void (*fx_ar_apfOpcodeTable[])();
extern void (*fx_ar_apfPlotTable[])();

/* Set this define if branches are relative to the instruction in the delay slot */
/* (I think they are) */
#define BRANCH_DELAY_RELATIVE

#endif