piwalker/gbemu
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

working on mooneye test suite

Browse Source
This commit is contained in:
Samuel Walker
2025-05-30 00:35:44 -06:00
parent 4d6973304d
commit 1f55455a65
7 changed files with 87 additions and 44 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
include/timer.h
View File

@ -7,6 +7,8 @@ typedef struct {
u8 tima;
u8 tma;
u8 tac;
bool tima_needs_reset;
bool tima_just_reset;
} timer_context;
typedef struct {

6
lib/cpu.c
View File

@ -18,7 +18,7 @@ FILE *log;
void cpu_init() {
ctx.regs.a = 0x01;
ctx.regs.f = 0xB0;
ctx.regs.b = 0x00;
ctx.regs.b = 0x19;
ctx.regs.c = 0x13;
ctx.regs.d = 0x00;
ctx.regs.e = 0xD8;
@ -55,6 +55,10 @@ static void execute() {
bool cpu_step() {
if(ctx.regs.pc == 0x4348) {
printf("made it!\n");
}
if(!ctx.halted) {
u16 pc = ctx.regs.pc;
fetch_instruction();

4
lib/cpu_fetch.c
View File

@ -74,7 +74,9 @@ void fetch_data() {
cpu_set_reg(RT_HL, cpu_read_reg(RT_HL)-1);
return;
case AM_R_A8:
ctx.fetched_data = bus_read(ctx.regs.pc);
u16 addr = bus_read(ctx.regs.pc) | 0xFF00;
emu_cycles(1);
ctx.fetched_data = bus_read(addr);
emu_cycles(1);
ctx.regs.pc++;
return;

31
lib/cpu_proc.c
View File

@ -2,6 +2,7 @@
#include <emu.h>
#include <bus.h>
#include <stack.h>
#include <timer.h>
reg_type decode_reg(u8 reg);
@ -51,7 +52,7 @@ static void proc_daa(cpu_context *ctx) {
ctx->regs.a += CPU_FLAG_N ? -u : u;
cpu_set_flags(ctx, ctx->regs.a == 0, -1, 0, fc);
cpu_set_flags(ctx, ctx->regs.a == 0, CPU_FLAG_N, 0, fc);
}
static void proc_cpl(cpu_context *ctx) {
@ -72,6 +73,7 @@ static void proc_halt(cpu_context *ctx) {
}
static void proc_stop(cpu_context *ctx) {
timer_get_context()->div = 0;
printf("CPU STOP!\n");
}
@ -303,10 +305,6 @@ static void proc_add(cpu_context *ctx) {
bool is_16bit = is_16_bit(ctx->cur_inst->reg_1);
if(is_16bit) {
emu_cycles(1);
}
if(ctx->cur_inst->reg_1 == RT_SP) {
val = cpu_read_reg(ctx->cur_inst->reg_1) + (char)ctx->fetched_data;
}
@ -329,6 +327,12 @@ static void proc_add(cpu_context *ctx) {
}
cpu_set_reg(ctx->cur_inst->reg_1, val & 0xFFFF);
if(is_16bit) {
emu_cycles(1);
}
if(ctx->cur_inst->reg_1 == RT_SP) {
emu_cycles(1);
}
cpu_set_flags(ctx, z, 0, h, c);
}
@ -358,10 +362,6 @@ static void proc_inc(cpu_context *ctx) {
static void proc_dec(cpu_context *ctx) {
u16 val = cpu_read_reg(ctx->cur_inst->reg_1) - 1;
if(is_16_bit(ctx->cur_inst->reg_1)) {
//emu_cycles(1);
}
if (ctx->cur_inst->reg_1 == RT_HL && ctx->dest_is_mem) {
val = ctx->fetched_data - 1;
val &= 0xFF;
@ -371,6 +371,10 @@ static void proc_dec(cpu_context *ctx) {
val = cpu_read_reg(ctx->cur_inst->reg_1);
}
if(is_16_bit(ctx->cur_inst->reg_1)) {
emu_cycles(1);
}
if((ctx->cur_opcode & 0x0B) == 0x0B) {
return;
}
@ -394,21 +398,20 @@ static void proc_pop(cpu_context *ctx) {
static void proc_push(cpu_context *ctx) {
u16 val = cpu_read_reg(ctx->cur_inst->reg_1);
emu_cycles(1);
stack_push((val >> 8) & 0xFF);
emu_cycles(1);
stack_push((val & 0xFF));
emu_cycles(1);
emu_cycles(1);
}
static void proc_ldh(cpu_context *ctx) {
if (!ctx->dest_is_mem) {
cpu_set_reg(ctx->cur_inst->reg_1, bus_read(0XFF00 | ctx->fetched_data));
cpu_set_reg(ctx->cur_inst->reg_1, ctx->fetched_data);
} else {
bus_write(0xFF00 | ctx->mem_dest, cpu_read_reg(ctx->cur_inst->reg_2));
emu_cycles(1);
}
emu_cycles(1);
}
static void proc_di(cpu_context *ctx) {
@ -458,12 +461,12 @@ static bool check_condition(cpu_context *ctx) {
static void goto_addr(cpu_context *ctx, u16 addr, bool pushpc){
if (check_condition(ctx)) {
emu_cycles(1);
if(pushpc) {
stack_push16(ctx->regs.pc);
emu_cycles(2);
}
ctx->regs.pc = addr;
emu_cycles(1);
}
}

12
lib/interrupts.c
View File

@ -7,7 +7,7 @@ void int_handle(cpu_context *ctx, u16 address) {
stack_push16(ctx->regs.pc);
emu_cycles(2);
ctx->regs.pc = address;
emu_cycles(1);
//emu_cycles(1);
}
bool int_check(cpu_context *ctx, u16 address, interrupt_type t){
@ -25,14 +25,14 @@ void cpu_request_interrupt(interrupt_type t);
void cpu_handle_interrupts(cpu_context *ctx) {
if (int_check(ctx, 0x40, IT_VBLANK)) {
//printf("VBLANK!\n");
} else if(int_check(ctx, 0x48, IT_LCD_STAT)){
//printf("LCD!\n");
} else if(int_check(ctx, 0x50, IT_TIMER)){
//printf("TIMER!\n");
} else if(int_check(ctx, 0x58, IT_SERIAL)){
//printf("Serial!\n");
} else if(int_check(ctx, 0x60, IT_JOYPAD)){
//printf("Joy!\n");
}
}

2
lib/io.c
View File

@ -37,7 +37,7 @@ u8 io_read(u16 address){
}
printf("UNSUPPORTED io_read(%04X)\n", address);
return 0;
return 0xFF;
}

74
lib/timer.c
View File

@ -5,40 +5,58 @@
static timer_context ctx = {0};
bool selected_bit() {
switch(ctx.tac & 0b11) {
case 0b00:
return (ctx.div & (1 << 9));
break;
case 0b01:
return (ctx.div & (1 << 3));
break;
case 0b10:
return (ctx.div & (1 << 5));
break;
case 0b11:
return (ctx.div & (1 << 7));
break;
}
}
void inc_tima() {
ctx.tima++;
if(ctx.tima == 0x00){
ctx.tima_needs_reset = true;
}
}
void timer_init() {
ctx.div = 0XAC00;
}
void timer_tick() {
u16 prev_div = ctx.div;
bool old = selected_bit();
ctx.div++;
bool timer_update = false;
switch(ctx.tac & 0b11) {
case 0b00:
timer_update = (prev_div & (1 << 9)) && (!(ctx.div & (1 << 9)));
break;
bool new = selected_bit();
case 0b01:
timer_update = (prev_div & (1 << 3)) && (!(ctx.div & (1 << 3)));
break;
case 0b10:
timer_update = (prev_div & (1 << 5)) && (!(ctx.div & (1 << 5)));
break;
case 0b11:
timer_update = (prev_div & (1 << 7)) && (!(ctx.div & (1 << 7)));
break;
}
if(timer_update && ctx.tac & (1 << 2)) {
ctx.tima++;
if(ctx.tima == 0xFF){
if((prev_div & (1 << 1)) && (!(ctx.div & (1 << 1)))){
if(ctx.tima_just_reset)
ctx.tima_just_reset = false;
if(ctx.tima_needs_reset){
ctx.tima = ctx.tma;
ctx.tima_needs_reset = false;
ctx.tima_just_reset = true;
cpu_request_interrupt(IT_TIMER);
}
}
if(ctx.tac & 0b100 && old && !new) {
inc_tima();
}
audio_sample_tick();
if((prev_div & (1 << 12)) && (!(ctx.div & (1 << 12)))){
@ -54,22 +72,36 @@ void timer_write(u16 address, u8 value){
switch(address) {
case 0xFF04:
//DIV
if(selected_bit()) {
inc_tima();
}
ctx.div = 0;
break;
case 0xFF05:
//TIMA
if(ctx.tima_just_reset)
return;
ctx.tima_needs_reset = false;
ctx.tima = value;
break;
case 0xFF06:
//TMA
if(ctx.tima_just_reset)
ctx.tima = value;
ctx.tma = value;
break;
case 0xFF07:
//TAC
bool current = selected_bit();
bool old_enable = ctx.tac & 0b100;
ctx.tac = value;
bool new = selected_bit();
if(((current && !new) && (ctx.tac & 0b100)) || (current && old_enable && !(ctx.tac & 0b100))) {
inc_tima();
}
break;
}
}