z80.c

DC的SEGA_GG模拟器源代码

/*****************************************************************************
 *
 *	 z80.c
 *	 Portable Z80 emulator V2.7
 *
 *	 Copyright (C) 1998,1999,2000 Juergen Buchmueller, all rights reserved.
 *
 *	 - This source code is released as freeware for non-commercial purposes.
 *	 - You are free to use and redistribute this code in modified or
 *	   unmodified form, provided you list me in the credits.
 *	 - If you modify this source code, you must add a notice to each modified
 *	   source file that it has been changed.  If you're a nice person, you
 *	   will clearly mark each change too.  :)
 *	 - If you wish to use this for commercial purposes, please contact me at
 *	   [e-mail]
 *	 - The author of this copywritten work reserves the right to change the
 *     terms of its usage and license at any time, including retroactively
 *   - This entire notice must remain in the source code.
 *
 *	 Changes in 2.7:
 *	  - removed z80_vm specific code, it's not needed (and never was).
 *   Changes in 2.6:
 *	  - BUSY_LOOP_HACKS needed to call change_pc16() earlier, before
 *		checking the opcodes at the new address, because otherwise they
 *		might access the old (wrong or even NULL) banked memory region.
 *		Thanks to Sean Young for finding this nasty bug.
 *   Changes in 2.5:
 *	  - Burning cycles always adjusts the ICount by a multiple of 4.
 *	  - In REPEAT_AT_ONCE cases the R register wasn't incremented twice
 *		per repetition as it should have been. Those repeated opcodes
 *		could also underflow the ICount.
 *	  - Simplified TIME_LOOP_HACKS for BC and added two more for DE + HL
 *		timing loops. I think those hacks weren't endian safe before too.
 *   Changes in 2.4:
 *	  - z80_reset zaps the entire context, sets IX and IY to 0xffff(!) and
 *		sets the Z flag. With these changes the Tehkan World Cup driver
 *		_seems_ to work again.
 *   Changes in 2.3:
 *	  - External termination of the execution loop calls z80_burn() and
 *		z80_vm_burn() to burn an amount of cycles (R adjustment)
 *	  - Shortcuts which burn CPU cycles (BUSY_LOOP_HACKS and TIME_LOOP_HACKS)
 *		now also adjust the R register depending on the skipped opcodes.
 *   Changes in 2.2:
 *	  - Fixed bugs in CPL, SCF and CCF instructions flag handling.
 *	  - Changed variable EA and ARG16() function to UINT32; this
 *		produces slightly more efficient code.
 *	  - The DD/FD XY CB opcodes where XY is 40-7F and Y is not 6/E
 *		are changed to calls to the X6/XE opcodes to reduce object size.
 *		They're hardly ever used so this should not yield a speed penalty.
 *	 New in 2.0:
 *    - Optional more exact Z80 emulation (#define Z80_EXACT 1) according
 *		to a detailed description by Sean Young which can be found at:
 *		http://www.msxnet.org/tech/Z80/z80undoc.txt
 *****************************************************************************/

#include "cpuintrf.h"
#include "z80.h"

#include "..\shared.h"
extern void cpu_writemem16(int address, int data);
extern void cpu_writeport(int port, int data);
extern int cpu_readport(int port);
unsigned char *cpu_readmap[8];
unsigned char *cpu_writemap[8];
#define cpu_readmem16(a)        cpu_readmap[(a) >> 13][(a) & 0x1FFF]
#define cpu_readop(a)           cpu_readmap[(a) >> 13][(a) & 0x1FFF]
#define cpu_readop_arg(a)       cpu_readmap[(a) >> 13][(a) & 0x1FFF]

/* execute main opcodes inside a big switch statement */
#ifndef BIG_SWITCH
#define BIG_SWITCH              1
#endif

/* big flags array for ADD/ADC/SUB/SBC/CP results */
#define BIG_FLAGS_ARRAY         1

/* Set to 1 for a more exact (but somewhat slower) Z80 emulation */
#define Z80_EXACT               1

/* repetitive commands (ldir,cpdr etc.) repeat at
   once until cycles used up or B(C) counted down. */
#define REPEAT_AT_ONCE		1

/* on JP and JR opcodes check for tight loops */
#define BUSY_LOOP_HACKS 	1

/* check for delay loops counting down BC */
#define TIME_LOOP_HACKS 	1

#ifdef X86_ASM
#undef	BIG_FLAGS_ARRAY
#define BIG_FLAGS_ARRAY 	0
#endif

#ifdef PSX
#undef  BIG_FLAGS_ARRAY
#define BIG_FLAGS_ARRAY         0
#endif

#define CF  0x01
#define NF	0x02
#define PF	0x04
#define VF	PF
#define XF	0x08
#define HF	0x10
#define YF	0x20
#define ZF	0x40
#define SF	0x80

#define INT_IRQ 0x01
#define NMI_IRQ 0x02

#define	_PPC	Z80.PREPC.d		/* previous program counter */

#define _PCD	Z80.PC.d
#define _PC 	Z80.PC.w.l

#define _SPD	Z80.SP.d
#define _SP 	Z80.SP.w.l

#define _AFD	Z80.AF.d
#define _AF 	Z80.AF.w.l
#define _A		Z80.AF.b.h
#define _F		Z80.AF.b.l

#define _BCD	Z80.BC.d
#define _BC 	Z80.BC.w.l
#define _B		Z80.BC.b.h
#define _C		Z80.BC.b.l

#define _DED	Z80.DE.d
#define _DE 	Z80.DE.w.l
#define _D		Z80.DE.b.h
#define _E		Z80.DE.b.l

#define _HLD	Z80.HL.d
#define _HL 	Z80.HL.w.l
#define _H		Z80.HL.b.h
#define _L		Z80.HL.b.l

#define _IXD	Z80.IX.d
#define _IX 	Z80.IX.w.l
#define _HX 	Z80.IX.b.h
#define _LX 	Z80.IX.b.l

#define _IYD	Z80.IY.d
#define _IY 	Z80.IY.w.l
#define _HY 	Z80.IY.b.h
#define _LY 	Z80.IY.b.l

#define _I      Z80.I
#define _R      Z80.R
#define _R2     Z80.R2
#define _IM     Z80.IM
#define _IFF1	Z80.IFF1
#define _IFF2	Z80.IFF2
#define _HALT	Z80.HALT

int z80_ICount;
static Z80_Regs Z80;
Z80_Regs *Z80_Context = &Z80;
static UINT32 EA;
int after_EI = 0;

static UINT8 SZ[256];		/* zero and sign flags */
static UINT8 SZ_BIT[256];	/* zero, sign and parity/overflow (=zero) flags for BIT opcode */
static UINT8 SZP[256];		/* zero, sign and parity flags */
static UINT8 SZHV_inc[256]; /* zero, sign, half carry and overflow flags INC r8 */
static UINT8 SZHV_dec[256]; /* zero, sign, half carry and overflow flags DEC r8 */
#include "z80daa.h"
#if BIG_FLAGS_ARRAY
#include <signal.h>
static UINT8 *SZHVC_add = 0;
static UINT8 *SZHVC_sub = 0;
#endif

#if Z80_EXACT
/* tmp1 value for ini/inir/outi/otir for [C.1-0][io.1-0] */
static UINT8 irep_tmp1[4][4] = {
	{0,0,1,0},{0,1,0,1},{1,0,1,1},{0,1,1,0}
};

/* tmp1 value for ind/indr/outd/otdr for [C.1-0][io.1-0] */
static UINT8 drep_tmp1[4][4] = {
	{0,1,0,0},{1,0,0,1},{0,0,1,0},{0,1,0,1}
};

/* tmp2 value for all in/out repeated opcodes for B.7-0 */
static UINT8 breg_tmp2[256] = {
	0,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,
	0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,
	0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,
	0,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,
	0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,
	0,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,
	0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1,
	0,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,1,0,0,1,0,1,1,0,0,1,1,0,1,0,0,
	1,0,1,1,0,1,0,0,1,1,0,0,1,0,1,1
};
#endif

static UINT8 cc_op[0x100] = {
 4,10, 7, 6, 4, 4, 7, 4, 4,11, 7, 6, 4, 4, 7, 4,
 8,10, 7, 6, 4, 4, 7, 4,12,11, 7, 6, 4, 4, 7, 4,
 7,10,16, 6, 4, 4, 7, 4, 7,11,16, 6, 4, 4, 7, 4,
 7,10,13, 6,11,11,10, 4, 7,11,13, 6, 4, 4, 7, 4,
 4, 4, 4, 4, 4, 4, 7, 4, 4, 4, 4, 4, 4, 4, 7, 4,
 4, 4, 4, 4, 4, 4, 7, 4, 4, 4, 4, 4, 4, 4, 7, 4,
 4, 4, 4, 4, 4, 4, 7, 4, 4, 4, 4, 4, 4, 4, 7, 4,
 7, 7, 7, 7, 7, 7, 4, 7, 4, 4, 4, 4, 4, 4, 7, 4,
 4, 4, 4, 4, 4, 4, 7, 4, 4, 4, 4, 4, 4, 4, 7, 4,
 4, 4, 4, 4, 4, 4, 7, 4, 4, 4, 4, 4, 4, 4, 7, 4,
 4, 4, 4, 4, 4, 4, 7, 4, 4, 4, 4, 4, 4, 4, 7, 4,
 4, 4, 4, 4, 4, 4, 7, 4, 4, 4, 4, 4, 4, 4, 7, 4,
 5,10,10,10,10,11, 7,11, 5, 4,10, 0,10,10, 7,11,
 5,10,10,11,10,11, 7,11, 5, 4,10,11,10, 0, 7,11,
 5,10,10,19,10,11, 7,11, 5, 4,10, 4,10, 0, 7,11,
 5,10,10, 4,10,11, 7,11, 5, 6,10, 4,10, 0, 7,11};


static UINT8 cc_cb[0x100] = {
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,12, 8, 8, 8, 8, 8, 8, 8,12, 8,
 8, 8, 8, 8, 8, 8,12, 8, 8, 8, 8, 8, 8, 8,12, 8,
 8, 8, 8, 8, 8, 8,12, 8, 8, 8, 8, 8, 8, 8,12, 8,
 8, 8, 8, 8, 8, 8,12, 8, 8, 8, 8, 8, 8, 8,12, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8,
 8, 8, 8, 8, 8, 8,15, 8, 8, 8, 8, 8, 8, 8,15, 8};

static UINT8 cc_dd[0x100] = {
 4, 4, 4, 4, 4, 4, 4, 4, 4,15, 4, 4, 4, 4, 4, 4,
 4, 4, 4, 4, 4, 4, 4, 4, 4,15, 4, 4, 4, 4, 4, 4,
 4,14,20,10, 9, 9, 9, 4, 4,15,20,10, 9, 9, 9, 4,
 4, 4, 4, 4,23,23,19, 4, 4,15, 4, 4, 4, 4, 4, 4,
 4, 4, 4, 4, 9, 9,19, 4, 4, 4, 4, 4, 9, 9,19, 4,
 4, 4, 4, 4, 9, 9,19, 4, 4, 4, 4, 4, 9, 9,19, 4,
 9, 9, 9, 9, 9, 9,19, 9, 9, 9, 9, 9, 9, 9,19, 9,
19,19,19,19,19,19, 4,19, 4, 4, 4, 4, 9, 9,19, 4,
 4, 4, 4, 4, 9, 9,19, 4, 4, 4, 4, 4, 9, 9,19, 4,
 4, 4, 4, 4, 9, 9,19, 4, 4, 4, 4, 4, 9, 9,19, 4,
 4, 4, 4, 4, 9, 9,19, 4, 4, 4, 4, 4, 9, 9,19, 4,
 4, 4, 4, 4, 9, 9,19, 4, 4, 4, 4, 4, 9, 9,19, 4,
 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 4, 4, 4, 4,
 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
 4,14, 4,23, 4,15, 4, 4, 4, 8, 4, 4, 4, 4, 4, 4,
 4, 4, 4, 4, 4, 4, 4, 4, 4,10, 4, 4, 4, 4, 4, 4};