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/* Nestra dynrec.c */
/* Public Domain */
#include <stdio.h>
#include "mapper.h"
#include "globals.h"
/* This is the dynamic recompiler. This takes 6502 code as input, looks
up the opcodes in the translation dictionary, evaluates any expressions
found therein, and writes the translated code to *(next_code_alloc++)
Pretty simple, huh? */
u_char *next_code_alloc=CODE_BASE;
/* Some declarataions for the asm code */
unsigned int VFLAG; /* Store overflow flag */
unsigned int FLAGS; /* Store 6502 process status reg */
unsigned int STACKPTR;/* Store 6502 stack pointer */
unsigned int PCR; /* Store 6502 program counter */
void *XPC; /* Translated program counter */
signed int INRET; /* Input data return value */
signed int CTNI; /* Cycles to next interrupt */
unsigned int VRAMPTR; /* address to read/write video memory */
unsigned int DMOD; /* Dest addr to modify */
unsigned int LASTBANK;/* Last memory page code executed in */
/* x86-specific definitions */
#define NOP 0x90
#define BRK 0xCC
translate(int addr)
{
int saddr;
u_char src;
unsigned int *ptr,*nptr;
unsigned char *sptr;
unsigned char *cptr,*bptr;
int slen,dlen;
int x;
u_char m,l,o;
u_char stop=0;
XPC=cptr=next_code_alloc;
if(disassemble)
{
printf("\n[%4x] (%8x) -> %8x\n",addr,(int)(MAPTABLE[addr>>12]+addr),cptr);fflush(stdout);
disas (addr); /* This will output a disassembly of the 6502 code */
}
while(!stop)
{
saddr=addr;
INT_MAP[(MAPTABLE[addr>>12]+addr)-RAM]=(unsigned int)cptr;
ptr=(int *)TRANS_TBL;
while(1)
{
src=*(MAPTABLE[addr>>12]+addr);
addr++;
/*printf("%x%x",src>>4,src&0xF);fflush(stdout);*/
if(ptr[src]==0) break;
if(ptr[src]&1) break;
ptr=(int *)(ptr[src]+(int)TRANS_TBL);
}
if(ptr[src]==0) {
addr=saddr+1;
/*printf("!%2x-NULL!",src);*/
if(!ignorebadinstr)
*(cptr++)=BRK;
}
else{
sptr=(u_char *)TRANS_TBL+ptr[src];
slen=sptr[-1];
dlen=x=*(sptr++);
bptr=cptr;
while(x--) *(cptr++)=*(sptr++);
while(*sptr!=0)
{
m=*(sptr++);l=*(sptr++);o=*(sptr++);
/*printf("[%c%d %d]",m,o,l);fflush(stdout);*/
if(m=='!') stop=1;
if(m=='B') bptr[l]=*(MAPTABLE[(saddr+o)>>12]+(saddr+o));
if(m=='C') bptr[l]=~*(MAPTABLE[(saddr+o)>>12]+(saddr+o));
if(m=='D') *((unsigned int *)(bptr+l))=(unsigned int)bptr+l+o;
if(m=='E') *((int *)(bptr+l))=*((signed char *)(MAPTABLE[(saddr+o)>>12]+(saddr+o)));
if(m=='Z') *((unsigned int *)(bptr+l))=(unsigned int)ZPMEM + *(MAPTABLE[(saddr+o)>>12]+saddr+o);
if(m=='A') *((unsigned int *)(bptr+l))=(unsigned int)RAM + *(MAPTABLE[(saddr+o)>>12]+saddr+o) + ((*(MAPTABLE[(saddr+o+1)>>12]+saddr+o+1))<<8);
if(m=='L') *((unsigned int *)(bptr+l))=(unsigned int)RAM;
if(m=='W') *((unsigned short *)(bptr+l))= *(MAPTABLE[(saddr+o)>>12]+saddr+o) + ((*(MAPTABLE[(saddr+o+1)>>12]+saddr+o+1))<<8);
if(m=='X') *((unsigned int *)(bptr+l))=(unsigned int)(MAPTABLE+((*(MAPTABLE[(saddr+o+1)>>12]+saddr+o+1))>>4));
if(m=='M') *((unsigned int *)(bptr+l))=(unsigned int)(MAPTABLE);
if(m=='T') *((unsigned int *)(bptr+l))=(unsigned int)STACK;
if(m=='P') *((unsigned short *)(bptr+l))=saddr+o;
if(m=='R') *((int *)(bptr+l))=*((signed char *)(MAPTABLE[(saddr+o)>>12]+saddr+o))+saddr+o+1;
if(m=='J') *((unsigned int *)(bptr+l))=*(MAPTABLE[(saddr+o)>>12]+saddr+o) + ((*(MAPTABLE[(saddr+o+1)>>12]+saddr+o+1))<<8);
if(m=='S') *((void **)(bptr+l))=&STACKPTR;
if(m=='V') *((void **)(bptr+l))=&VFLAG;
if(m=='F') *((void **)(bptr+l))=&FLAGS;
if(m=='I') *((int *)(bptr+l))=(int)(&INPUT)-(int)(bptr+l)-4;
if(m=='O') *((int *)(bptr+l))=(int)(&OUTPUT)-(int)(bptr+l)-4;
if(m=='U') *((int *)(bptr+l))=(int)(&U)-(int)(bptr+l)-4;
if(m=='N') *((int *)(bptr+l))=(int)(&NMI)-(int)(bptr+l)-4;
if(m=='Y') *((int *)(bptr+l))=(int)(Mapper[MAPPERNUMBER])-(int)(bptr+l)-4;
if(m=='>') bptr[l]+=(((*((signed char *)(MAPTABLE[(saddr+o)>>12]+saddr+o))+saddr+o+1)&0xFF00)!=((saddr+o+1)&0xFF00));
if(m=='^') bptr[l]=ignorebadinstr?NOP:BRK;
}
addr=saddr+slen;
}
}
while(((int)cptr&15)!=0) *(cptr++)=NOP;
next_code_alloc=cptr;
}
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