mirror of
https://github.com/raxracks/6502.git
synced 2024-12-02 00:11:10 +13:00
first commit
This commit is contained in:
commit
b26428cdee
12 changed files with 378 additions and 0 deletions
7
Makefile
Normal file
7
Makefile
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@ -0,0 +1,7 @@
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emulator: emulator.c
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gcc emulator.c -o emulator -g -Iinclude
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hello: hello.asm
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ca65 hello.asm -o hello.o
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ld65 hello.o -o hello -C config.cfg
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run: hello emulator
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./emulator hello
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9
config.cfg
Normal file
9
config.cfg
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@ -0,0 +1,9 @@
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MEMORY {
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RAM: start = $0000, size = $4000, type = rw;
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ROM: start = $8000, size = $8000, type = ro;
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}
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SEGMENTS {
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CODE: load = "ROM", type = ro;
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DATA: load = "ROM", type = ro;
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}
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BIN
emulator
Executable file
BIN
emulator
Executable file
Binary file not shown.
272
emulator.c
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272
emulator.c
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#include <stdio.h>
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#include <slibs/slibs.h>
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#include <stdint.h>
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#include <assert.h>
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#define NEGATIVE 1 << 7
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#define OVERFLOW 1 << 6
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#define BREAK 1 << 4
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#define DECIMAL 1 << 3
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#define INTERRUPT 1 << 2
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#define ZERO 1 << 1
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#define CARRY 1 << 0
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typedef struct {
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uint8_t A;
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uint8_t X;
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uint8_t Y;
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uint8_t SP;
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uint8_t P;
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uint16_t PC;
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} CPU;
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CPU cpu = { 0 };
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uint8_t* memory;
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int main(int argc, char** argv) {
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assert(argc > 1);
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sl_string code = { 0 };
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sl_read_file(argv[1], &code);
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memory = malloc(sizeof(uint8_t) * 0xffff);
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memcpy(memory + 0x8000, code.data, code.size);
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for(cpu.PC = 0; cpu.PC < code.size; cpu.PC++) {
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uint8_t opcode = code.data[cpu.PC];
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uint8_t one = code.data[cpu.PC + 1];
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uint8_t two = code.data[cpu.PC + 2];
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uint16_t word = (two << 8) | one;
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uint8_t h_nib = (opcode >> 4) & 0xF;
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uint8_t l_nib = opcode & 0xF;
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printf("%d: 0x%02X (h_nib: 0x%X, l_nib: 0x%X)\n", cpu.PC, opcode, h_nib, l_nib);
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switch(h_nib) {
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case 0x8:
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switch(l_nib) {
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case 0x1:
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printf(" ∟ STA ($%02X, X)\n", one);
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memory[memory[one + cpu.X]] = cpu.A;
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cpu.PC++;
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break;
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case 0x5:
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printf(" ∟ STA $%02X\n", one);
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memory[one] = cpu.A;
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cpu.PC++;
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break;
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case 0x6:
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printf(" ∟ STX $%02X\n", one);
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memory[one] = cpu.X;
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cpu.PC++;
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break;
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case 0xD:
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printf(" ∟ STA $%04X\n", word);
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memory[word] = cpu.A;
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cpu.PC += 2;
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break;
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case 0xE:
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printf(" ∟ STX $%04X\n", word);
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memory[word] = cpu.X;
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cpu.PC += 2;
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break;
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}
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break;
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case 0x9:
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switch(l_nib) {
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case 0x1:
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printf(" ∟ STA ($%02X), Y\n", one);
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memory[memory[one] + cpu.Y] = cpu.A;
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cpu.PC++;
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break;
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case 0x5:
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printf(" ∟ STA $%02X, X\n", word);
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memory[one + cpu.X] = cpu.A;
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cpu.PC++;
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break;
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case 0x9:
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printf(" ∟ STA $%04X, Y\n", word);
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memory[word + cpu.Y] = cpu.A;
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cpu.PC += 2;
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break;
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case 0xD:
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printf(" ∟ STA $%04X, X\n", word);
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memory[word + cpu.X] = cpu.A;
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cpu.PC += 2;
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break;
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}
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break;
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case 0xA:
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switch(l_nib) {
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case 0x0:
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printf(" ∟ LDY #$%02X\n", one);
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cpu.Y = one;
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cpu.PC++;
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break;
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case 0x1:
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printf(" ∟ LDA ($%02X, X)\n", one);
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cpu.A = memory[memory[one + cpu.X]];
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printf("addr: %x val: %x\n", memory[one + cpu.X], cpu.A);
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cpu.PC++;
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break;
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case 0x2:
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printf(" ∟ LDX #$%02X\n", one);
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cpu.X = one;
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cpu.PC++;
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break;
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case 0x4:
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printf(" ∟ LDY $%02X\n", one);
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cpu.Y = memory[one];
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cpu.PC++;
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break;
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case 0x5:
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printf(" ∟ LDA $%02X\n", one);
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cpu.A = memory[one];
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cpu.PC++;
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break;
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case 0x6:
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printf(" ∟ LDX $%02X\n", one);
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cpu.X = memory[one];
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cpu.PC++;
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break;
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case 0x9:
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printf(" ∟ LDA #$%02X\n", one);
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cpu.A = one;
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cpu.PC++;
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break;
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case 0xC:
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printf(" ∟ LDY $%04X\n", word);
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cpu.Y = memory[word];
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cpu.PC += 2;
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break;
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case 0xD:
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printf(" ∟ LDA $%04X\n", word);
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cpu.A = memory[word];
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cpu.PC += 2;
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break;
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case 0xE:
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printf(" ∟ LDX $%04X\n", word);
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cpu.X = memory[word];
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cpu.PC += 2;
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break;
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}
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break;
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case 0xB:
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switch(l_nib) {
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case 0x1:
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printf(" ∟ LDA ($%02X), Y\n", one);
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cpu.A = memory[memory[one] + cpu.Y];
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printf("addr: %x val: %x\n", memory[one] + cpu.Y, cpu.A);
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cpu.PC++;
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break;
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case 0x4:
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printf(" ∟ LDY $%02X, X\n", one);
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cpu.Y = memory[one + cpu.X];
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printf("addr: %x val: %x\n", one + cpu.X, cpu.Y);
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cpu.PC++;
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break;
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case 0x5:
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printf(" ∟ LDA $%02X, X\n", one);
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cpu.A = memory[one + cpu.X];
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printf("addr: %x val: %x\n", one + cpu.X, cpu.A);
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cpu.PC++;
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break;
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case 0x6:
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printf(" ∟ LDX $%02X, Y\n", one);
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cpu.X = memory[one + cpu.Y];
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printf("addr: %x val: %x\n", one + cpu.Y, cpu.X);
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cpu.PC++;
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break;
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case 0x9:
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printf(" ∟ LDA $%04X, Y\n", word);
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cpu.A = memory[word + cpu.Y];
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printf("addr: %x val: %x\n", word + cpu.Y, cpu.A);
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cpu.PC++;
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break;
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case 0xC:
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printf(" ∟ LDY $%04X, X\n", word);
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cpu.Y = memory[word + cpu.X];
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printf("addr: %x val: %x\n", word + cpu.X, cpu.Y);
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cpu.PC += 2;
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break;
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case 0xD:
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printf(" ∟ LDA $%04X, X\n", word);
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cpu.A = memory[word + cpu.X];
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printf("addr: %x val: %x\n", word + cpu.X, cpu.A);
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cpu.PC += 2;
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break;
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case 0xE:
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printf(" ∟ LDX $%04X, Y\n", word);
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cpu.X = memory[word + cpu.Y];
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printf("addr: %x val: %x\n", word + cpu.Y, cpu.X);
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cpu.PC += 2;
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break;
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}
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break;
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case 0xC:
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switch(l_nib) {
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case 0x8:
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printf(" ∟ INY\n");
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cpu.Y++;
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break;
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}
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break;
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case 0xE:
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switch(l_nib) {
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case 0x6:
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printf(" ∟ INC $%02X\n", one);
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memory[one]++;
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cpu.PC++;
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break;
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case 0x8:
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printf(" ∟ INX\n");
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cpu.X++;
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break;
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case 0xE:
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printf(" ∟ INC $%04X\n", word);
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memory[word]++;
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cpu.PC += 2;
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break;
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}
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break;
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case 0xF:
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switch(l_nib) {
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case 0x6:
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printf(" ∟ INC $%02X, X\n", one);
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memory[one + cpu.X]++;
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cpu.PC++;
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break;
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case 0xE:
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printf(" ∟ INC $%04X, X\n", word);
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memory[word + cpu.X]++;
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cpu.PC += 2;
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break;
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}
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break;
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default:
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printf(" ∟ Unimplemented\n");
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break;
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}
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}
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printf("CPU State:\n"
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"A\t:\t0x%08X\n"
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"X\t:\t0x%08X\n"
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"Y\t:\t0x%08X\n"
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"SP\t:\t0x%08X\n"
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"P\t:\t0x%08X\n"
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"PC\t:\t0x%016X\n\n"
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, cpu.A, cpu.X, cpu.Y, cpu.SP, cpu.P, cpu.PC);
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printf("Memory State:\n");
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for(int i = 0; i < 0xffff; i++) {
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if(memory[i] != 0x0) {
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printf("0x%04X: 0x%02X (0b%08b)\n", i, memory[i], memory[i]);
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}
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}
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return 0;
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}
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40
game.asm
Normal file
40
game.asm
Normal file
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.segment "CODE"
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.proc main
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main:
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; Initialize PPU
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LDA #%10000000 ; Set the bit 7 to $2000 to use $2000-$2FFF for nametables
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STA $2000
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LDA #%00011110 ; Enable rendering, enable sprites, and make sure background is visible
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STA $2001
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; Load sprite data into OAM
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LDX #0 ; Initialize X register to zero
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LDA SpriteData,X ; Load the first byte of sprite data
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STA $0200,X ; Store it in the Object Attribute Memory (OAM)
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INX ; Increment X to load the next byte
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LDA SpriteData,X ; Load the second byte of sprite data (attributes)
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STA $0200,X ; Store it in OAM
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INX ; Increment X to load the next byte (X position)
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LDA SpriteData,X ; Load the third byte of sprite data (X position)
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STA $0200,X ; Store it in OAM
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; Infinite loop
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forever:
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JMP forever
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.endproc
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.segment "DATA"
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SpriteData:
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.byte $00 ; Tile index for the sprite
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.byte $20 ; Attributes (palette, flipping, etc.)
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.byte $80 ; X position of the sprite
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; Additional sprite data can be added here
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.segment "BSS"
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; Define uninitialized memory (if needed)
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BIN
hello
Normal file
BIN
hello
Normal file
Binary file not shown.
4
hello.asm
Normal file
4
hello.asm
Normal file
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@ -0,0 +1,4 @@
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LDA #10
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LDX #$1
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STA $20
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INC $2000, X
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BIN
hello.o
Normal file
BIN
hello.o
Normal file
Binary file not shown.
BIN
helloworld.nes
Normal file
BIN
helloworld.nes
Normal file
Binary file not shown.
39
implemented.txt
Normal file
39
implemented.txt
Normal file
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==== LDA (completed) ====
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LDA #
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LDA $ (Z)
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LDA $ (A)
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LDA $, X (Z)
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LDA $, X (A)
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LDA $, Y (A)
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LDA ($, X)
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LDA ($), Y
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==== LDX (completed) ====
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LDX #
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LDX $ (Z)
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LDX $ (A)
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LDX $, Y (Z)
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LDX $, Y (A)
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==== LDY (completed) ====
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LDY #
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LDY $ (Z)
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LDY $ (A)
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LDY $, X (Z)
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LDY $, X (A)
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==== STA (completed) ====
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STA $ (Z)
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STA $ (A)
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STA $, X (Z)
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STA $, X (A)
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STA ($, X)
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STA ($), Y
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==== INC (completed) ====
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INX
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INY
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INC $ (Z)
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INC $ (A)
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INC $, X (Z)
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INC $, X (A)
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1
include/slibs
Submodule
1
include/slibs
Submodule
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@ -0,0 +1 @@
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Subproject commit 63edb9343b6787883a667b69ece86bde005ab311
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6
temp.asm
Normal file
6
temp.asm
Normal file
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@ -0,0 +1,6 @@
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LDA hello, X
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INX
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LDA hello, X
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.DATA
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hello: .byte "hello world", 0
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Loading…
Add table
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