about to try to integrate imgui again

cli/emulator.c

@@ -32,9 +32,9 @@ int main(int argc, char *argv[])
     dmg_new(&dmg, &cpu, &rom, &lcd);
     cpu_bind_mem_model(&cpu, &dmg, dmg_read, dmg_write);
 
-    cpu.pc = 0;
+    cpu.pc = 0x100;
 
-    // for (executed = 0; executed < 100000; executed++) {
+    // for (executed = 0; executed < 1000; executed++) {
     while (1) {
         dmg_step(&dmg);
     }

src/cpu.c

@@ -306,7 +306,9 @@ static void extended_insn(struct cpu *cpu, u8 insn)
         shift_right // TODO SRL
     };
 
+#ifdef GB6_DEBUG
     printf("       %s\n", instructions[insn + 0x100].format);
+#endif
     cpu->cycle_count += instructions[insn + 0x100].cycles;
 
     switch (op) {
@@ -337,7 +339,9 @@ void cpu_step(struct cpu *cpu)
     u8 temp;
     u16 temp16;
     u8 opc = cpu->mem_read(cpu->mem_model, cpu->pc);
+#ifdef GB6_DEBUG
     printf("0x%04x %s\n", cpu->pc, instructions[opc].format);
+#endif
     cpu->pc++;
     cpu->cycle_count += instructions[opc].cycles;
     switch (opc) {

src/dmg.c

@@ -77,6 +77,13 @@ void dmg_step(void *_dmg)
 
     // each line takes 456 cycles
     if (dmg->cpu->cycle_count % 456 == 0) {
-        lcd_step(dmg->lcd);
+        int next_scanline = lcd_step(dmg->lcd);
+        if (next_scanline == 144) {
+            // vblank has started, draw all the stuff from ram into the lcd
+
+            // now copy 256x256 buf to 160x144 based on window registers
+            lcd_copy(dmg->lcd);
+            lcd_draw(dmg->lcd);
+        }
     }
 }

src/lcd.c

@@ -1,5 +1,6 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "types.h"
 #include "lcd.h"
@@ -16,23 +17,34 @@ static void clear_bit(struct lcd *lcd, u16 addr, u8 bit)
 
 void lcd_new(struct lcd *lcd)
 {
+    lcd->buf = malloc(256 * 256);
     // todo < 8 bpp
     lcd->pixels = malloc(LCD_WIDTH * LCD_HEIGHT);
 }
 
 u8 lcd_is_valid_addr(u16 addr)
 {
-    return addr >= REG_LCD_BASE && addr <= REG_LCD_LAST;
+    return (addr >= 0xfe00 && addr < 0xfea0) || (addr >= REG_LCD_BASE && addr <= REG_LCD_LAST);
 }
 
 u8 lcd_read(struct lcd *lcd, u16 addr)
 {
+    if (addr >= 0xfe00 && addr < 0xfea0) {
+        return lcd->oam[addr - 0xfe00];
+    }
     return lcd->regs[addr - REG_LCD_BASE];
 }
 
 void lcd_write(struct lcd *lcd, u16 addr, u8 value)
 {
-    lcd->regs[addr - REG_LCD_BASE] = value;
+    if (addr >= 0xfe00 && addr < 0xfea0) {
+        lcd->oam[addr - 0xfe00] = value;
+    } else {
+        lcd->regs[addr - REG_LCD_BASE] = value;
+        if (addr == 0xFF46) {
+            // OAM DMA
+        }
+    }
 }
 
 void lcd_put_pixel(struct lcd *lcd, u8 x, u8 y, u8 value)
@@ -44,7 +56,13 @@ void lcd_put_pixel(struct lcd *lcd, u8 x, u8 y, u8 value)
     lcd->pixels[y * LCD_WIDTH + x] = value;
 }
 
-void lcd_step(struct lcd *lcd)
+void lcd_copy(struct lcd *lcd)
+{
+    // use all the registers to compute the pixel data
+
+}
+
+int lcd_step(struct lcd *lcd)
 {
     // update LYC
     if (lcd_read(lcd, REG_LY) == lcd_read(lcd, REG_LYC)) {
@@ -56,5 +74,7 @@ void lcd_step(struct lcd *lcd)
     // step to next scanline 0-153
     u8 next_scanline = (lcd_read(lcd, REG_LY) + 1) % 154;
     lcd_write(lcd, REG_LY, next_scanline);
+
+    return next_scanline;
     // printf("update lcd %d\n", next_scanline);
 }

src/lcd.h

@@ -25,9 +25,20 @@
 
 #define STAT_FLAG_MATCH 2
 
+#define LCDC_ENABLE_BG (1 << 0)
+#define LCDC_ENABLE_OBJ (1 << 1)
+#define LCDC_OBJ_SIZE (1 << 2)
+#define LCDC_BG_TILE_MAP (1 << 3)
+#define LCDC_BG_TILE_DATA (1 << 4)
+#define LCDC_ENABLE_WINDOW (1 << 5)
+#define LCDC_WINDOW_TILE_MAP (1 << 6)
+#define LCDC_ENABLE (1 << 7)
+
 struct lcd {
+    u8 oam[0xa0];
     u8 regs[0x0c];
-    u8 *pixels;
+    u8 *buf; // 256x256
+    u8 *pixels; // the actual 160x144 visible area
 };
 
 void lcd_new(struct lcd *lcd);
@@ -38,8 +49,10 @@ void lcd_write(struct lcd *lcd, u16 addr, u8 value);
 void lcd_put_pixel(struct lcd *lcd, u8 x, u8 y, u8 value);
 
 // i feel like i'm going to need to call this every cycle and update regs
-void lcd_step(struct lcd *lcd);
+int lcd_step(struct lcd *lcd);
+void lcd_copy(struct lcd *lcd);
 
+// output the pixels to the screen
 void lcd_draw(struct lcd *lcd);
 
 #endif