1 line
97 KiB
C
1 line
97 KiB
C
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/*
MINEM68K.c
Copyright (C) 2009 Bernd Schmidt, Paul C. Pratt
You can redistribute this file and/or modify it under the terms
of version 2 of the GNU General Public License as published by
the Free Software Foundation. You should have received a copy
of the license along with this file; see the file COPYING.
This file 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
license for more details.
*/
/*
MINimum EMulator of 68K cpu
This code descends from a simple 68000 emulator that I
(Paul C. Pratt) wrote long ago. That emulator ran on a 680x0,
and used the cpu it ran on to do some of the work. This
descendent fills in those holes with code from the
Un*x Amiga Emulator by Bernd Schmidt, as found being used in vMac.
This emulator is about 10 times smaller than the UAE,
at the cost of being 2 to 3 times slower.
FPU Emulation added 9/12/2009 by Ross Martin
(this code now located in "FPCPEMDV.h")
*/
#ifndef AllFiles
#include "SYSDEPNS.h"
#include "MYOSGLUE.h"
#include "ENDIANAC.h"
#include "EMCONFIG.h"
#include "GLOBGLUE.h"
#include "M68KITAB.h"
#if WantDisasm
#include "DISAM68K.h"
#endif
#endif
#include "MINEM68K.h"
typedef unsigned char flagtype;
/* Memory Address Translation Cache record */
struct MATCr {
ui5r cmpmask;
ui5r cmpvalu;
ui5r usemask;
ui3p usebase;
};
typedef struct MATCr MATCr;
typedef MATCr *MATCp;
/*
This variable was introduced because a program could do a Bcc from
within chip memory to a location within expansion memory. With a
pointer variable the program counter would point to the wrong
location. With this variable unset the program counter is always
correct, but programs will run slower (about 4%).
Usually, you'll want to have this defined.
vMac REQUIRES this. It allows for fun things like Restart.
*/
#ifndef USE_POINTER
#define USE_POINTER 1
#endif
#define AKMemory 0
#define AKRegister 1
#define AKConstant 2
union ArgAddrT {
ui5r mem;
ui5r *rga;
};
typedef union ArgAddrT ArgAddrT;
LOCALVAR struct regstruct
{
ui5r regs[16]; /* Data and Address registers */
ui5r pc; /* Program Counter */
CPTR usp; /* User Stack Pointer */
CPTR isp; /* Interrupt Stack Pointer */
#if Use68020
CPTR msp; /* Master Stack Pointer */
#endif
/* Status Register */
ui5r intmask; /* bits 10-8 : interrupt priority mask */
flagtype t1; /* bit 15: Trace mode 1 */
#if Use68020
flagtype t0; /* bit 14: Trace mode 0 */
#endif
flagtype s; /* bit 13: Supervisor or user privilege level */
#if Use68020
flagtype m; /* bit 12: Master or interrupt mode */
#endif
flagtype x; /* bit 4: eXtend */
flagtype n; /* bit 3: Negative */
flagtype z; /* bit 2: Zero */
flagtype v; /* bit 1: oVerflow */
flagtype c; /* bit 0: Carry */
flagtype TracePending;
flagtype ExternalInterruptPending;
#if 0
flagtype ResetPending;
#endif
ui3b *fIPL;
#if Use68020
ui5b sfc; /* Source Function Code register */
ui5b dfc; /* Destination Function Code register */
ui5b vbr; /* Vector Base Register */
ui5b cacr; /* Cache Control Register */
/*
bit 0 : Enable Cache
bit 1 : Freeze Cache
bit 2 : Clear Entry In Cache (write only)
bit 3 : Clear Cache (write only)
*/
ui5b caar; /* Cache Address Register */
#endif
MATCr MATCrdB;
MATCr MATCwrB;
MATCr MATCrdW;
MATCr MATCwrW;
MATCr MATCex;
ATTep HeadATTel;
DecOpR CurDecOp;
#if USE_POINTER
ui3p pc_p;
ui3p pc_oldp;
#endif
ui5b opsize;
ui5b ArgKind;
ArgAddrT ArgAddr;
ui5b SrcVal;
ui5b opcode;
si5r MaxCyclesToGo;
si5r MoreCyclesToGo;
si5r ResidualCycles;
ui3b fakeword[2];
#define disp_table_sz (256 * 256)
#if SmallGlobals
DecOpR *disp_table;
#else
DecOpR disp_table[disp_table_sz];
#endif
} regs;
#define ui5r_MSBisSet(x) (((si5r)(x)) < 0)
#define ZFLG regs.z
#define NFLG regs.n
#define CFLG regs.c
#define VFLG regs.v
#define XFLG regs.x
LOCALFUNC ui4b m68k_getCR(void)
{
return (XFLG << 4) | (NFLG << 3) | (ZFLG << 2)
| (VFLG << 1) | CFLG;
}
LOCALFUNC MayInline void m68k_setCR(ui4b newcr)
{
XFL
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