test out BitUnpack, fix bugs.

examples/hello.rs

@@ -1,7 +1,7 @@
 #![no_std]
 #![no_main]
 
-use core::fmt::Write;
+use core::{fmt::Write, mem::size_of_val};
 use gba::{
   mgba::{MgbaBufferedLogger, MgbaMessageLevel},
   prelude::*,
@@ -36,7 +36,20 @@ extern "C" fn main() -> ! {
     writeln!(logger, "hello!").ok();
   }
 
-  DISPCNT.write(DisplayControl::new().with_show_bg0(true));
+  {
+    // get our tile data into memory.
+    //let src = ;
+    let dest = CHARBLOCK0_4BPP.index(0).as_usize() as *mut u32;
+    let info = BitUnpackInfo {
+      src_byte_len: size_of_val(&CGA_8X8_THICK) as u16,
+      src_elem_width: 1,
+      dest_elem_width: 4,
+      offset_and_touch_zero: 0,
+    };
+    unsafe { BitUnPack(CGA_8X8_THICK.as_ptr().cast::<u8>(), dest, &info) };
+  }
+
+  DISPCNT.write(DisplayControl::new().with_show_bg2(true));
 
   loop {
     VBlankIntrWait();

src/bios.rs

@@ -106,9 +106,9 @@ pub struct BitUnpackInfo {
 /// * `dest` must be 4 byte aligned.
 #[inline]
 #[instruction_set(arm::t32)]
-pub unsafe fn BitUnPack(src: *mut u8, dest: *mut u32, info: &BitUnpackInfo) {
+pub unsafe fn BitUnPack(src: *const u8, dest: *mut u32, info: &BitUnpackInfo) {
   core::arch::asm! {
-    "swi #0x05",
+    "swi #0x10",
     inout("r0") src => _,
     inout("r1") dest => _,
     inout("r2") info => _,

src/builtin_art/cga_8x8_thick.rs

@@ -8,7 +8,7 @@
 /// # use core::mem::size_of_val;
 /// let src = CGA_8X8_THICK.as_ptr().cast::<u8>();
 ///
-/// let dest = CHARBLOCK0_4BPP.as_usize() as *mut u32;
+/// let dest = CHARBLOCK0_4BPP.index(0).as_usize() as *mut u32;
 ///
 /// let info = BitUnpackInfo {
 ///   src_byte_len: size_of_val(&CGA_8X8_THICK) as u16,
@@ -35,7 +35,7 @@
 /// https://en.wikipedia.org/wiki/Intellectual_property_protection_of_typefaces
 ///
 /// [df-tiles]: https://dwarffortresswiki.org/Tileset_repository#8.C3.978
-pub const CGA_8X8_THICK: [u32; 512] = [
+pub static CGA_8X8_THICK: [u32; 512] = [
   // Note(Lokathor): I generated this by (1) converting the type face file from
   // an RGB PNG to Indexed Color PNG using GIMP, (2) running `grit
   // CGA8x8thick-indexed.png -gB1` to output an assembly file full of the