Write a custom tile copy command

agb/src/agbabi/mod.rs

@@ -4,14 +4,6 @@ global_asm!(include_str!("macros.inc"));
 global_asm!(include_str!("memcpy.s"));
 global_asm!(include_str!("memset.s"));
 
-extern "C" {
-    fn __aeabi_memcpy4(dest: *mut u32, src: *const u32, n: usize);
-}
-
-pub(crate) unsafe fn memcpy(dest: *mut u32, src: *const u32, n: usize) {
-    __aeabi_memcpy4(dest, src, n);
-}
-
 #[cfg(test)]
 mod test {
     mod memset {

agb/src/display/tiled/tile_copy.s

@@ -0,0 +1,27 @@
+agb_arm_func copy_tile_8bpp
+    @ Arguments
+    @ r0 - pointer to the image data beginning
+    @ r1 - pointer to the target in vram
+    push {{r4-r8}}
+
+.rept 2
+    ldmia r0!, {{r2-r8, r12}}
+    stmia r1!, {{r2-r8, r12}}
+.endr
+
+    pop {{r4-r8}}
+    bx lr
+agb_arm_end copy_tile_8bpp
+
+agb_arm_func copy_tile_4bpp
+    @ Arguments
+    @ r0 - pointer to the image data beginning
+    @ r1 - pointer to the target in vram
+    push {{r4-r8}}
+
+    ldmia r0!, {{r2-r8, r12}}
+    stmia r1!, {{r2-r8, r12}}
+
+    pop {{r4-r8}}
+    bx lr
+agb_arm_end copy_tile_4bpp

agb/src/display/tiled/vram_manager.rs

@@ -4,7 +4,6 @@ use alloc::{slice, vec::Vec};
 
 use crate::{
     agb_alloc::{block_allocator::BlockAllocator, bump_allocator::StartEnd},
-    agbabi,
     display::palette16,
     dma::dma_copy16,
     hash_map::{Entry, HashMap},
@@ -381,11 +380,13 @@ impl VRamManager {
         let tile_offset = (tile_id as usize) * tile_size;
         let tile_slice = &tile_set.tiles[tile_offset..(tile_offset + tile_size)];
 
-        let tile_size = tile_slice.len();
         let target_location = tile_reference.0.as_ptr() as *mut _;
 
         unsafe {
-            agbabi::memcpy(target_location, tile_slice.as_ptr() as *const _, tile_size);
+            match tile_set.format {
+                TileFormat::FourBpp => copy_tile_4bpp(tile_slice.as_ptr().cast(), target_location),
+                TileFormat::EightBpp => copy_tile_8bpp(tile_slice.as_ptr().cast(), target_location),
+            }
         }
     }
 
@@ -409,3 +410,8 @@ impl VRamManager {
         }
     }
 }
+
+extern "C" {
+    fn copy_tile_4bpp(src: *const u32, dest: *mut u32);
+    fn copy_tile_8bpp(src: *const u32, dest: *mut u32);
+}

agb/src/global_asm.rs

@@ -6,3 +6,4 @@ global_asm!(include_str!("crt0.s"));
 global_asm!(include_str!("interrupt_handler.s"));
 global_asm!(include_str!("sound/mixer/mixer.s"));
 global_asm!(include_str!("save/asm_routines.s"));
+global_asm!(include_str!("display/tiled/tile_copy.s"));