134 lines
3.3 KiB
C
134 lines
3.3 KiB
C
#include <stdint.h>
|
|
#include <stdio.h>
|
|
#include "emulator.h"
|
|
|
|
/* Register I6 maintains common status */
|
|
#define _R0 0xb0
|
|
#define _R8 0xd0
|
|
#define _I0 0xd8
|
|
#define _I6 0xf0
|
|
#define _I7 0xf4
|
|
#define _I8 0xf8
|
|
|
|
/* (dd cc bb aa) aa: index for register stack RS / ccbb: program counter PC / dd: flags F UONPZLGE */
|
|
#define _RSI _I6 /* register stack index */
|
|
#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 allocated */
|
|
#define _ARLL _I7 /* allocated low and high bytes */
|
|
#define _ARLH _ARLL + 1
|
|
#define _ARUL _ARLH + 1 /* allocated upper limit */
|
|
#define _ARUH _ARUL + 1
|
|
#define _AR _ARLL /* allocated memory address */
|
|
|
|
/* section modifiers */
|
|
#define _SM_FXD 0x01
|
|
#define _SM_RLC 0x02
|
|
#define _SM_CD 0x04
|
|
#define _SM_DT 0x08
|
|
|
|
/* section identifiers */
|
|
#define _RLC_CD _SM_RLC + _SM_CD /* relocatable code */
|
|
#define _RLC_DT _SM_RLC + _SM_DT /* relocatable data */
|
|
|
|
uint8_t memory[65536];
|
|
|
|
/* Functions for emulator */
|
|
uint8_t read6502(uint16_t address);
|
|
void write6502(uint16_t address, uint8_t value);
|
|
void hook();
|
|
|
|
int main() {
|
|
|
|
uint8_t header[5];
|
|
/* where to start relocatables */
|
|
uint16_t index = 0x0600;
|
|
|
|
while (fread(header, sizeof(header), 1, stdin))
|
|
{
|
|
uint8_t type = header[0];
|
|
uint16_t entity = header[1] + (header[2] << 8);
|
|
uint16_t length = header[3] + (header[4] << 8);
|
|
|
|
printf("\n%x %04x %u\n", type, entity, length);
|
|
|
|
switch (type) {
|
|
case _SM_FXD: /* fixed code or data */
|
|
/* entity is the address, length is the length of the code or data */
|
|
fread(memory + entity, length, 1, stdin);
|
|
break;
|
|
|
|
case _RLC_CD: /* relocatable code */
|
|
/* entity is the starting offset, length is the length of code */
|
|
if (fread(memory + index, length, 1, stdin)) {
|
|
/* offset the starting address */
|
|
entity += index;
|
|
/* save the starting address */
|
|
memory[_PCL] = entity & 0xff;
|
|
memory[_PCH] = entity >> 8;
|
|
/* advance to the end of the section */
|
|
index += length;
|
|
}
|
|
break;
|
|
|
|
case _RLC_DT: /* relocatable data */
|
|
/* entity is the length of zeroed data, length is the length of preset data */
|
|
if (fread(memory + index, length, 1, stdin)) {
|
|
/* save the start of the data */
|
|
memory[_ARLL] = index & 0xff;
|
|
memory[_ARLH] = index >> 8;
|
|
/* advance to the end of the section */
|
|
index += entity + length;
|
|
/* save the end of the data */
|
|
memory[_ARUL] = index & 0xff;
|
|
memory[_ARUH] = index >> 8;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
hookexternal(hook);
|
|
|
|
reset6502();
|
|
|
|
/* TODO: access irq6502(); on a timer */
|
|
|
|
do
|
|
step6502();
|
|
while (memory[pc]);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
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");
|
|
}
|
|
}
|