6 files changed, 54 insertions, 11 deletions

diff --git a/README.md b/README.md
new file mode 100644
index 0000000..975201c
--- /dev/null
+++ b/README.md
@@ -0,0 +1,40 @@
+# UXNGBA
+
+This is a port of the [UXN virtual machine][uxn] for the GBA. It is currently at
+an early stage, but is capable of running simple demos that make use of the
+screen or console devices, including the beautiful DVD bouncing.
+
+[uxn]: https://wiki.xxiivv.com/site/uxn.html
+
+## Building from source
+
+To build this software you need the [devkitPro][devkitpro] SDK. Once installed,
+You may need to modify the Makefile to set up the path:
+
+```
+DEVKITPRO  := /opt/devkitpro
+DEVKITARM  := /opt/devkitpro/devkitARM
+PATH       := $(DEVKITARM)/bin:$(PATH)
+LIBGBA_DIR := $(DEVKITPRO)/libgba
+LIBGBA_SRC := /opt/devkitpro/libgba/include/
+LIBGBA     := $(LIBGBA_DIR)/lib/libgba.a
+LIBGBA     += $(LIBGBA_DIR)/lib/libfat.a
+LIBGBA     += $(LIBGBA_DIR)/lib/libmm.a
+```
+
+An intermediate build step will create a `src/uxn/roms/boot.c` file, for which
+you need the `bin2carr` utility that can be found [here][bin2carr].
+
+If everything is properly installed, you should be able to run `make` to compile
+the program into a `uxngba.gba` rom. If you have `mgba-qt` installed, you can
+test it with: `make run`.
+
+To use a specific UXN compiled rom, you can pass it as the `ROM_SRC` make
+parameter:
+
+```
+make run ROM_SRC=src/uxn/roms/piano.rom
+```
+
+[devkitpro]: https://devkitpro.org/
+[bin2carr]: https://git.badd10de.dev/gba-dev-tools/
diff --git a/src/main.c b/src/main.c
index c302480..e91a2f2 100644
--- a/src/main.c
+++ b/src/main.c
@@ -142,9 +142,9 @@ int main(void) {
         evaluxn(&u, mempeek16(devscreen->dat, 0));
         flipbuf(&ppu);
         int eval_cycles = profile_stop();
-        txt_position(0,0);
-        txt_printf("FRAME: %d              \n", frame_counter);
-        txt_printf("EVAL:  %d              \n", eval_cycles);
+        // txt_position(0,0);
+        // txt_printf("FRAME: %d              \n", frame_counter);
+        // txt_printf("EVAL:  %d              \n", eval_cycles);
         drawing_cycles = 0;
         frame_counter++;
     }
diff --git a/src/uxn/devices/ppu.c b/src/uxn/devices/ppu.c
index 0935329..d70afdd 100644
--- a/src/uxn/devices/ppu.c
+++ b/src/uxn/devices/ppu.c
@@ -167,8 +167,8 @@ putpixel(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 color) {
     size_t tile_y = y / 8;
     size_t start_col = x % 8;
     size_t start_row = y % 8;
-    Uint32 pos = (start_row + ((tile_x + tile_y * 30) * 8));
-    Uint32 shift = start_col * 4;
+    size_t pos = (start_row + ((tile_x + tile_y * 30) * 8));
+    size_t shift = start_col * 4;
     layer[pos] = (layer[pos] & (~(0xF << shift))) | (color << shift);
     dirty_tiles[tile_y] |= 1 << tile_x;
 }
@@ -180,13 +180,16 @@ puticn(Ppu *p, Uint32 *layer, Uint16 x, Uint16 y, Uint8 *sprite, Uint8 color,
     size_t tile_y = y / 8;
     size_t start_col = x % 8;
     size_t start_row = y % 8;
-    Uint32 pos = (start_row + ((tile_x + tile_y * 30) * 8));
-    Uint32 shift_left = start_col * 4;
-    Uint32 shift_right = (8 - start_col) * 4;
-        Uint32 *layer_ptr = &layer[pos];
-        if (flipy) flipy = 7;
+    size_t shift_left = start_col * 4;
+    size_t shift_right = (8 - start_col) * 4;
 
-        Uint32 *lut = flipx ? unpack_icon_lut : unpack_icon_lut_flipx;
+        if (flipy) {
+        flipy = 7;
+    }
+
+    size_t pos = (start_row + ((tile_x + tile_y * 30) * 8));
+        size_t *layer_ptr = &layer[pos];
+        size_t *lut = flipx ? unpack_icon_lut : unpack_icon_lut_flipx;
 
     // There are 4 possible cases:
     // 1. The sprite is exactly at the tile boundary. We can just copy the
diff --git a/src/uxn/roms/automata.rom b/src/uxn/roms/automata.rom
new file mode 100644
index 0000000..57c505c
--- /dev/null
+++ b/src/uxn/roms/automata.rom
diff --git a/src/uxn/roms/dvd.rom b/src/uxn/roms/dvd.rom
new file mode 100644
index 0000000..4de8d72
--- /dev/null
+++ b/src/uxn/roms/dvd.rom
diff --git a/src/uxn/roms/piano.rom b/src/uxn/roms/piano.rom
new file mode 100644
index 0000000..0556ccf
--- /dev/null
+++ b/src/uxn/roms/piano.rom