COMMON/emulator/main.c

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#include <stdint.h>
#include <stdio.h>
#include "emulator.h"
/* Register I6 maintains common status */
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#define _R0 0xb0
#define _R8 0xd0
#define _I0 0xd8
#define _I6 0xf0
#define _I7 0xf4
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#define _I8 0xf8
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/* (dd cc bb aa) aa: index for register stack RS / ccbb: program counter PC / dd: flags F UONPZLGE */
#define _RSI _I6 /* register stack index */
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#define _PCL _RSI + 1 /* program counter low */
#define _PCH _PCL + 1 /* program counter high */
#define _F _PCH + 1 /* flags */
#define _PC _PCL /* program counter */
/* register I7 maintains locations of code and allocated memory */
#define _CRL _I7 /* code low and high bytes */
#define _CRH _CRL + 1
#define _ARL _CRH + 1 /* allocated low and high bytes */
#define _ARH _ARL + 1
#define _CR _CRL /* code memory address */
#define _AR _ARL /* allocated memory address */
#define CODE 0xaa /* to indicate CODE section */
#define DATA 0x55 /* to indicate DATA section */
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uint8_t memory[65536];
uint8_t read6502(uint16_t address) {
return memory[address];
}
void write6502(uint16_t address, uint8_t value) {
memory[address] = value;
}
void hook() {
int i, j;
printf("\n%04x %u %u\n", pc, instructions, clockticks6502);
for (i = _R0; i < _R8; i += 4) {
printf("R%d: ", (i - _R0) / 4);
for (j = 0; j < 4; ++j)
printf("%02x ", memory[i + j]);
if (((i - _R0) / 4) % 4 == 3)
printf("\n");
}
for (i = _I0; i < _I8; i += 4) {
printf("I%d: ", (i - _I0) / 4);
for (j = 0; j < 4; ++j)
printf("%02x ", memory[i + j]);
if (((i - _I0) / 4) % 4 == 3)
printf("\n");
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}
}
int main() {
uint8_t header[5];
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while (fread(header, sizeof(header), 1, stdin))
{
uint8_t type = header[0];
uint16_t index = header[1] + (header[2] << 8);
uint16_t length = header[3] + (header[4] << 8);
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printf("\n%x %04x %u\n", type, index, length);
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if (fread(memory + index, length, 1, stdin))
{
switch (type) {
case CODE:
memory[_CRL] = header[1];
memory[_CRH] = header[2];
break;
case DATA:
memory[_ARL] = header[1];
memory[_ARH] = header[2];
break;
}
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}
}
memory[_PCL] = memory[_CRL];
memory[_PCH] = memory[_CRH];
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hookexternal(hook);
reset6502();
do
step6502();
while (memory[pc]);
return 0;
}