85 lines
2.7 KiB
C
85 lines
2.7 KiB
C
#include <fcntl.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <malloc.h>
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#include <string.h>
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#include <sys/mman.h>
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#define RAMSIZE 0x1000
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extern uint32_t instructions;
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extern void reset6502(void);
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extern void step6502(void);
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uint8_t *ram, *screen, *f000;
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uint8_t read6502(uint16_t address) {
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if (address == _END) {
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printf("DONE\n");
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exit(0);
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}
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uint8_t value = 0x00;
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if (address < RAMSIZE) {
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if (address >= RAMSIZE-16) {
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// emulate memory error in uppermost page
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value = ram[address] & 0xf7;
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} else if (address >= 0x0100 && address <= 0x01ff) {
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// simulate broken LSB in stack page
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value = ram[address & 0xfffe];
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} else {
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value = ram[address];
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}
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printf("%08x: READ %04x -> %02x\n", instructions, address, value);
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} else if (address >= 0x8000 && address <= 0x8fff) {
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// screen buffer is mirrored 4 times, discard upper 2 bytes
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value = screen[address & 0x03ff];
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printf("%08x: READ %04x -> %02x\n", instructions, address, value);
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} else if (address >= 0xf000) {
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value = f000[address-0xf000];
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printf("%08x: READ %04x -> %02x\n", instructions, address, value);
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} else {
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printf("%08x: READ %04x -> not implemented\n", instructions, address);
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}
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return value;
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}
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void write6502(uint16_t address, uint8_t value) {
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if (address < RAMSIZE) {
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printf("%08x: WRITE %04x <- %02x\n", instructions, address, value);
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// simulate broken LSB in stack page
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if (address >= 0x100 && address <= 0x1ff) {
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ram[address & 0xfffe] = value;
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} else {
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ram[address] = value;
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}
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} else if (address >= 0x8000 && address <= 0x8fff) {
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printf("%08x: WRITE %04x <- %02x, SCREEN(%d,%d)\n", instructions, address, value, (address&0x03ff)%40, (address&0x03ff)/40);
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screen[address & 0x03ff] = value;
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} else {
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printf("%08x: WRITE %04x <- %02x; READONLY\n", instructions, address, value);
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}
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}
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int main() {
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ram = (uint8_t*) malloc(RAMSIZE);
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screen = (uint8_t*) malloc(0x400);
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memset(screen, 'X', 0x400);
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int ffd = open("memtest-f000.901465+ascii.bin", O_RDONLY);
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f000 = mmap(0, 0x1000, PROT_READ, MAP_PRIVATE, ffd, 0);
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reset6502();
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while (1) {
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usleep(1);
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step6502();
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printf("pass: %02x, address: %02x%02x\n", ram[4], ram[1], ram[2]);
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printf("┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓\n");
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for (uint8_t row = 0; row < 25; ++row) {
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printf("┃%.40s┃\n", screen + 40*row);
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}
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printf("┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛\n");
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}
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}
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