segfault

cmd/go6502/main.go

@@ -15,7 +15,7 @@ func run() {
 
 	deviceMap, err := bus.New(
 		bus.NewRam(0x0, 0x1000),
-		bus.NewRom(0x8000, "./code/blinkc"),
+		bus.NewRom(0x8000, "./code/graphics"),
 		graphics.CreatePPU(0x1000),
 		imu,
 	)

code/Makefile

@@ -1,4 +1,7 @@
 
+GFX_FILES = gfx/gfx.c
+GFX = $(patsubst %.c,%.o,$(GFX_FILES))
+
 %.o: %.s
 	ca65 -o $@ $^ -t none
 
@@ -9,5 +12,8 @@
 	cl65 -o $@ $^ -t none -c
 
 
+graphics: graphics.o $(GFX) reset.o
+	ld65 -o $@ $^ none.lib -C link.ld
+
 blinkc: blinkc.o reset.o
 	ld65 -o $@ $^ -C link.ld

code/gfx/gfx.c

@@ -0,0 +1,27 @@
+#include "gfx.h"
+#include <stdint.h>
+
+char * video_buffer;
+uint8_t width;
+uint8_t height;
+
+void gfx_init(uintptr_t video_buffer_address, uint8_t w, uint8_t h) {
+    video_buffer = (char *)video_buffer_address;
+    width = w;
+    height = h;
+}
+
+void clear(color_t color) {
+    uint8_t i;
+    uint8_t j;
+
+    for (i = 0; i < width; ++i) {
+        for (j = 0; j < height; ++j) {
+            video_buffer[j * width + i] = color;
+        }
+    }
+}
+
+color_t get_color(Palette p, uint8_t index) {
+    return (uint8_t) p << 5 | index && 0b11111;
+}

code/gfx/gfx.h

@@ -0,0 +1,27 @@
+
+#ifndef GFX_H
+#define GFX_H
+
+#include <stdint.h>
+
+extern char * video_buffer;
+extern uint8_t width;
+extern uint8_t height;
+
+typedef uint8_t color_t;
+
+void gfx_init(uintptr_t video_buffer_address, uint8_t w, uint8_t h);
+void clear(color_t color);
+
+typedef enum {
+    Palette0 = 0,
+    Endesga = 1,
+    Clear = 2,
+
+    GrayPalette = 7,
+} Palette;
+
+
+color_t get_color(Palette p, uint8_t index);
+
+#endif

code/graphics.c

@@ -0,0 +1,10 @@
+#include "gfx/gfx.h"
+
+void reset() {
+    color_t red;
+
+    gfx_init(0x1000, 64, 64);
+
+    red = get_color(Endesga, 3);
+    clear(red);
+}

code/link.ld

@@ -22,6 +22,10 @@ SEGMENTS {
         load = RAM1
         type=bss
         define=yes;
+    ZEROPAGE:
+        load = RAM1
+        type = zp
+        define = yes;
     RESET:
         load = ROM1
         start = $fffa