mirror of
https://github.com/Russell-S-Harper/COMMON.git
synced 2024-12-18 00:29:35 +00:00
134 lines
3.3 KiB
C
134 lines
3.3 KiB
C
#include <stdint.h>
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#include <stdio.h>
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#include "emulator.h"
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/* Register I6 maintains common status */
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#define _R0 0xb0
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#define _R8 0xd0
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#define _I0 0xd8
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#define _I6 0xf0
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#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 */
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#define _RSI _I6 /* register stack index */
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#define _PCL _RSI + 1 /* program counter low */
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#define _PCH _PCL + 1 /* program counter high */
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#define _F _PCH + 1 /* flags */
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#define _PC _PCL /* program counter */
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/* register I7 maintains locations of allocated */
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#define _ARLL _I7 /* allocated low and high bytes */
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#define _ARLH _ARLL + 1
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#define _ARUL _ARLH + 1 /* allocated upper limit */
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#define _ARUH _ARUL + 1
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#define _AR _ARLL /* allocated memory address */
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/* section modifiers */
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#define _SM_FXD 0x01
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#define _SM_RLC 0x02
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#define _SM_CD 0x04
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#define _SM_DT 0x08
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/* section identifiers */
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#define _RLC_CD _SM_RLC + _SM_CD /* relocatable code */
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#define _RLC_DT _SM_RLC + _SM_DT /* relocatable data */
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uint8_t memory[65536];
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/* Functions for emulator */
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uint8_t read6502(uint16_t address);
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void write6502(uint16_t address, uint8_t value);
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void hook();
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int main() {
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uint8_t header[5];
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/* where to start relocatables */
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uint16_t index = 0x0600;
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while (fread(header, sizeof(header), 1, stdin))
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{
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uint8_t type = header[0];
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uint16_t entity = header[1] + (header[2] << 8);
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uint16_t length = header[3] + (header[4] << 8);
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printf("\n%x %04x %u\n", type, entity, length);
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switch (type) {
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case _SM_FXD: /* fixed code or data */
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/* entity is the address, length is the length of the code or data */
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fread(memory + entity, length, 1, stdin);
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break;
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case _RLC_CD: /* relocatable code */
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/* entity is the starting offset, length is the length of code */
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if (fread(memory + index, length, 1, stdin)) {
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/* offset the starting address */
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entity += index;
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/* save the starting address */
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memory[_PCL] = entity & 0xff;
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memory[_PCH] = entity >> 8;
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/* advance to the end of the section */
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index += length;
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}
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break;
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case _RLC_DT: /* relocatable data */
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/* entity is the length of zeroed data, length is the length of preset data */
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if (fread(memory + index, length, 1, stdin)) {
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/* save the start of the data */
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memory[_ARLL] = index & 0xff;
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memory[_ARLH] = index >> 8;
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/* advance to the end of the section */
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index += entity + length;
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/* save the end of the data */
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memory[_ARUL] = index & 0xff;
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memory[_ARUH] = index >> 8;
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}
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break;
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}
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}
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hookexternal(hook);
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reset6502();
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/* TODO: access irq6502(); on a timer */
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do
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step6502();
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while (memory[pc]);
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return 0;
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}
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uint8_t read6502(uint16_t address) {
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return memory[address];
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}
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void write6502(uint16_t address, uint8_t value) {
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memory[address] = value;
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}
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void hook() {
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int i, j;
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printf("\n%04x %u %u\n", pc, instructions, clockticks6502);
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for (i = _R0; i < _R8; i += 4) {
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printf("R%d: ", (i - _R0) / 4);
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for (j = 0; j < 4; ++j)
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printf("%02x ", memory[i + j]);
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if (((i - _R0) / 4) % 4 == 3)
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printf("\n");
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}
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for (i = _I0; i < _I8; i += 4) {
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printf("I%d: ", (i - _I0) / 4);
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for (j = 0; j < 4; ++j)
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printf("%02x ", memory[i + j]);
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if (((i - _I0) / 4) % 4 == 3)
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printf("\n");
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}
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}
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