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gbdb: remove some conditionals from mem_read()

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By reading directly from a "RAM" array, and copying in the cart data
over the old bootrom.

Also, some other fixups because I'm too lazy to properly split patches
for a personal project.
This commit is contained in:
Max Regan
2018-07-02 05:24:36 +00:00
parent 1bb3d8512a
commit 213c08fa18
4 changed files with 12 additions and 15 deletions
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15
src/apps/gbdb.c
View File

@@ -19,7 +19,7 @@
#include "common/tri.h"
#define INPUT_MAX_LEN 512
#define MAX_BREAKPTS 2 /* Should be plenty for anyone */
#define MAX_BREAKPTS 16 /* Should be plenty for anyone */
#define MAX_RAM_LEN (1 << 20) /* Up to 8Mb Cartridge */
#define UNMAP_BOOTROM_ADDR 0xff50
@@ -46,6 +46,7 @@ static struct lr35902_state cpu;
static struct gb_video video;
static unsigned char bootrom[0x100] = {0};
static unsigned char cart_low[0x100] = {0};
static int bootrom_mapped = 1;
@@ -97,12 +98,6 @@ static uint8_t mem_read(struct lr35902_state *cpu, uint16_t addr)
{
switch (addr) {
case 0 ... 0x100-1:
if (bootrom_mapped) {
return bootrom[addr];
} else {
return ram[addr];
}
case 0xFF40 ... 0xFF4B:
return gb_video_mem_read(&video, addr);
default:
@@ -117,6 +112,7 @@ static void mem_write(struct lr35902_state *cpu, uint16_t addr, uint8_t val)
case UNMAP_BOOTROM_ADDR:
if (val == 1) {
bootrom_mapped = 0;
memcpy(ram, cart_low, sizeof(cart_low));
gb_log("bootrom unmapped\n");
}
break;
@@ -375,7 +371,7 @@ static void assert(char *arg_list)
return;
fail:
printf("ASSERT: %s %s %s\n", val0_str, operator_str, val1_str);
printf("%s=%ld, %s=%ld\n", val0_str, val0, val1_str, val1);
printf("%s=%lld, %s=%lld\n", val0_str, val0, val1_str, val1);
regs(NULL);
stats(NULL);
exit(1);
@@ -449,6 +445,8 @@ static void load(char *arg_list)
strip_newline(token);
load_file_to_buffer(token, ram, sizeof(ram));
load_file_to_buffer(token, cart_low, sizeof(cart_low));
}
static void load_bootrom(char *arg_list)
@@ -461,6 +459,7 @@ static void load_bootrom(char *arg_list)
strip_newline(token);
load_file_to_buffer(token, bootrom, sizeof(bootrom));
load_file_to_buffer(token, ram, sizeof(bootrom));
}

4
src/gbemu/cpu.c
View File

@@ -326,12 +326,10 @@ void lr35902_cycle(struct lr35902_state *cpu)
if (cpu->stall_cycles > 0) {
cpu->stall_cycles--;
if (cpu->stall_cycles == 0) {
cpu->metrics.retired_instrs++;
}
return;
}
cpu->metrics.retired_instrs++;
inst = cpu->mem_read(cpu, cpu->pc++);
cpu->stall_cycles = op_extra_cycles[inst];

7
src/gbemu/video.c
View File

@@ -14,16 +14,15 @@ void gb_video_init(struct gb_video *video)
void gb_video_cycle(struct gb_video *video)
{
video->line_counter++;
if (video->line_counter >= CYCLES_PER_LINE) {
if (video->line_counter < CYCLES_PER_LINE - 1) {
video->line_counter++;
} else {
video->line_counter = 0;
video->curline += 1;
if (video->curline > LCD_Y_MAX) {
video->curline = 0;
}
}
}
uint8_t gb_video_mem_read(struct gb_video *video, uint16_t addr)