Implement memory device

The memory device is fully implemented, with 3MB of heap memory.

This commit is a bit messy, additional changes are:
- The program memory and program counter in each Bedrock struct have
  been moved to a dedicated struct to prevent a name collision with the
  memory device
- The run_bg and debug functions have been moved to core.c and debug.c
- The blank screen colour has been changed back to black
- No second program runs on the sub screen by default
- The number of Bedrock instances to run has been parameterized

1 files changed, 24 insertions, 0 deletions

diff --git a/arm9/source/debug.c b/arm9/source/debug.c
new file mode 100644
index 0000000..eae5192
--- /dev/null
+++ b/arm9/source/debug.c
@@ -0,0 +1,24 @@
+#include <nds.h>
+#include "core.h"
+
+void debug_stacks(Bedrock *br) {
+    u8 i;
+    printf("\nP:0x%04x   I:0x%02x", PC, MEM[PC]);
+    printf("\nW:");
+    for (i=0; i<WST.p; i++) {
+        printf("%02x ", WST.mem[i]);
+    }
+    printf("\nR:");
+    for (i=0; i<RST.p; i++) {
+        printf("%02x ", RST.mem[i]);
+    }
+    printf("\n");
+}
+
+void debug_assert(Bedrock *br) {
+    if (WST.mem[0] == 0xff && WST.p == 1 && RST.p == 0) {
+        printf(".");
+    } else {
+        printf("X");
+    }
+}