Merge pull request #783 from Missingmew/unused-decompress

Decompile unref_sub_800D42C

3 files changed, 144 insertions, 351 deletions

diff --git a/asm/decompress.s b/asm/decompress.s
deleted file mode 100644
index 99e449d8f..000000000
--- a/asm/decompress.s
+++ /dev/null
@@ -1,350 +0,0 @@
-	.include "constants/gba_constants.inc"
-
-	.include "include/macros.inc"
-
-	.syntax unified
-
-	.text
-	
-	thumb_func_start unref_sub_800D42C
-unref_sub_800D42C: @ 800D42C
-	push {r4-r7,lr}
-	mov r7, r10
-	mov r6, r9
-	mov r5, r8
-	push {r5-r7}
-	sub sp, 0x24
-	mov r9, r0
-	str r1, [sp]
-	str r2, [sp, 0x4]
-	adds r5, r3, 0
-	movs r0, 0x1
-	mov r1, r9
-	ands r0, r1
-	cmp r0, 0
-	bne _0800D44C
-	b _0800D5E4
-_0800D44C:
-	asrs r0, r1, 1
-	adds r0, 0x4
-	lsls r0, 24
-	lsrs r0, 24
-	str r0, [sp, 0x8]
-	movs r0, 0
-	ldr r2, [sp]
-	cmp r0, r2
-	blt _0800D460
-	b _0800D674
-_0800D460:
-	movs r4, 0x8
-	subs r1, r4, r1
-	str r1, [sp, 0x10]
-_0800D466:
-	movs r7, 0
-	adds r0, 0x1
-	str r0, [sp, 0x14]
-	ldr r0, [sp, 0x10]
-	cmp r7, r0
-	bge _0800D4E2
-	ldr r1, [sp, 0x8]
-	lsls r1, 8
-	str r1, [sp, 0x18]
-	movs r2, 0
-	mov r10, r2
-	mov r0, r9
-	movs r4, 0x8
-	subs r0, r4, r0
-	str r0, [sp, 0xC]
-_0800D484:
-	movs r3, 0
-	asrs r0, r7, 1
-	adds r1, r7, 0
-	movs r2, 0x1
-	ands r1, r2
-	str r1, [sp, 0x20]
-	lsls r0, 8
-	mov r8, r0
-	mov r12, r5
-_0800D496:
-	lsls r1, r3, 5
-	ldr r4, [sp, 0x18]
-	adds r0, r5, r4
-	adds r0, r1
-	mov r1, r8
-	adds r2, r0, r1
-	mov r1, r12
-	add r1, r8
-	movs r6, 0xF
-_0800D4A8:
-	ldr r4, [sp, 0x20]
-	cmp r4, 0
-	bne _0800D4B8
-	strb r4, [r1]
-	add r4, sp, 0x20
-	ldrb r4, [r4]
-	strb r4, [r2, 0x10]
-	b _0800D4C6
-_0800D4B8:
-	mov r0, r10
-	strb r0, [r1, 0x10]
-	movs r4, 0x80
-	lsls r4, 1
-	adds r4, r2, r4
-	str r4, [sp, 0x1C]
-	strb r0, [r4]
-_0800D4C6:
-	adds r2, 0x1
-	adds r1, 0x1
-	subs r6, 0x1
-	cmp r6, 0
-	bge _0800D4A8
-	movs r0, 0x20
-	add r12, r0
-	adds r3, 0x1
-	cmp r3, 0x7
-	ble _0800D496
-	adds r7, 0x1
-	ldr r1, [sp, 0xC]
-	cmp r7, r1
-	blt _0800D484
-_0800D4E2:
-	movs r7, 0
-	movs r2, 0
-_0800D4E6:
-	movs r6, 0
-	adds r4, r7, 0x1
-	mov r8, r4
-	lsls r4, r7, 5
-_0800D4EE:
-	adds r0, r6, 0x1
-	mov r10, r0
-	lsls r1, r6, 8
-	adds r0, r1, 0
-	adds r0, 0xC0
-	adds r0, r5, r0
-	adds r0, r4
-	adds r1, r5, r1
-	adds r1, r4
-	movs r3, 0x1F
-_0800D502:
-	strb r2, [r1]
-	strb r2, [r0]
-	adds r0, 0x1
-	adds r1, 0x1
-	subs r3, 0x1
-	cmp r3, 0
-	bge _0800D502
-	mov r6, r10
-	cmp r6, 0x7
-	ble _0800D4EE
-	mov r7, r8
-	cmp r7, 0x1
-	ble _0800D4E6
-	mov r1, r9
-	cmp r1, 0x5
-	bne _0800D528
-	movs r2, 0x90
-	lsls r2, 1
-	adds r5, r2
-_0800D528:
-	movs r7, 0
-	cmp r7, r9
-	bge _0800D5BE
-_0800D52E:
-	movs r3, 0
-	adds r7, 0x1
-	mov r8, r7
-	cmp r3, r9
-	bge _0800D59E
-_0800D538:
-	adds r3, 0x1
-	mov r10, r3
-	ldr r4, [sp, 0x4]
-	adds r4, 0x20
-	adds r7, r5, 0
-	adds r7, 0x20
-	movs r0, 0x12
-	adds r0, r5
-	mov r12, r0
-	ldr r2, [sp, 0x4]
-	adds r3, r5, 0
-	movs r6, 0x3
-_0800D550:
-	ldrb r0, [r2]
-	mov r1, r12
-	strb r0, [r1]
-	ldrb r0, [r2, 0x1]
-	strb r0, [r1, 0x1]
-	ldrb r0, [r2, 0x2]
-	strb r0, [r1, 0x1E]
-	ldrb r0, [r2, 0x3]
-	strb r0, [r1, 0x1F]
-	movs r0, 0x81
-	lsls r0, 1
-	adds r1, r3, r0
-	ldrb r0, [r2, 0x10]
-	strb r0, [r1]
-	ldr r0, _0800D5A8 @ =0x00000103
-	adds r1, r3, r0
-	ldrb r0, [r2, 0x11]
-	strb r0, [r1]
-	movs r0, 0x90
-	lsls r0, 1
-	adds r1, r3, r0
-	ldrb r0, [r2, 0x12]
-	strb r0, [r1]
-	ldr r0, _0800D5AC @ =0x00000121
-	adds r1, r3, r0
-	ldrb r0, [r2, 0x13]
-	strb r0, [r1]
-	movs r1, 0x4
-	add r12, r1
-	adds r2, 0x4
-	adds r3, 0x4
-	subs r6, 0x1
-	cmp r6, 0
-	bge _0800D550
-	str r4, [sp, 0x4]
-	adds r5, r7, 0
-	mov r3, r10
-	cmp r3, r9
-	blt _0800D538
-_0800D59E:
-	mov r2, r9
-	cmp r2, 0x7
-	bne _0800D5B0
-	adds r5, 0x20
-	b _0800D5B8
-	.align 2, 0
-_0800D5A8: .4byte 0x00000103
-_0800D5AC: .4byte 0x00000121
-_0800D5B0:
-	mov r4, r9
-	cmp r4, 0x5
-	bne _0800D5B8
-	adds r5, 0x60
-_0800D5B8:
-	mov r7, r8
-	cmp r7, r9
-	blt _0800D52E
-_0800D5BE:
-	mov r0, r9
-	cmp r0, 0x7
-	bne _0800D5CC
-	movs r1, 0x80
-	lsls r1, 1
-	adds r5, r1
-	b _0800D5D8
-_0800D5CC:
-	mov r2, r9
-	cmp r2, 0x5
-	bne _0800D5D8
-	movs r4, 0xF0
-	lsls r4, 1
-	adds r5, r4
-_0800D5D8:
-	ldr r0, [sp, 0x14]
-	ldr r1, [sp]
-	cmp r0, r1
-	bge _0800D5E2
-	b _0800D466
-_0800D5E2:
-	b _0800D674
-_0800D5E4:
-	movs r6, 0
-	ldr r2, [sp]
-	cmp r6, r2
-	bge _0800D674
-_0800D5EC:
-	adds r6, 0x1
-	mov r10, r6
-	mov r4, r9
-	cmp r4, 0x6
-	bne _0800D604
-	movs r0, 0
-	movs r3, 0xFF
-_0800D5FA:
-	strb r0, [r5]
-	adds r5, 0x1
-	subs r3, 0x1
-	cmp r3, 0
-	bge _0800D5FA
-_0800D604:
-	movs r7, 0
-	cmp r7, r9
-	bge _0800D658
-_0800D60A:
-	adds r7, 0x1
-	mov r8, r7
-	mov r1, r9
-	lsls r0, r1, 5
-	cmp r1, 0x6
-	bne _0800D624
-	movs r1, 0
-	movs r3, 0x1F
-_0800D61A:
-	strb r1, [r5]
-	adds r5, 0x1
-	subs r3, 0x1
-	cmp r3, 0
-	bge _0800D61A
-_0800D624:
-	adds r1, r0, 0
-	cmp r1, 0
-	ble _0800D63E
-	adds r3, r1, 0
-_0800D62C:
-	ldr r2, [sp, 0x4]
-	ldrb r0, [r2]
-	strb r0, [r5]
-	adds r2, 0x1
-	str r2, [sp, 0x4]
-	adds r5, 0x1
-	subs r3, 0x1
-	cmp r3, 0
-	bne _0800D62C
-_0800D63E:
-	mov r4, r9
-	cmp r4, 0x6
-	bne _0800D652
-	movs r0, 0
-	movs r3, 0x1F
-_0800D648:
-	strb r0, [r5]
-	adds r5, 0x1
-	subs r3, 0x1
-	cmp r3, 0
-	bge _0800D648
-_0800D652:
-	mov r7, r8
-	cmp r7, r9
-	blt _0800D60A
-_0800D658:
-	mov r0, r9
-	cmp r0, 0x6
-	bne _0800D66C
-	movs r0, 0
-	movs r3, 0xFF
-_0800D662:
-	strb r0, [r5]
-	adds r5, 0x1
-	subs r3, 0x1
-	cmp r3, 0
-	bge _0800D662
-_0800D66C:
-	mov r6, r10
-	ldr r1, [sp]
-	cmp r6, r1
-	blt _0800D5EC
-_0800D674:
-	add sp, 0x24
-	pop {r3-r5}
-	mov r8, r3
-	mov r9, r4
-	mov r10, r5
-	pop {r4-r7}
-	pop {r0}
-	bx r0
-	thumb_func_end unref_sub_800D42C
-
-	.align 2, 0
diff --git a/ld_script.txt b/ld_script.txt
index 46004c7c7..2606c7d1a 100644
--- a/ld_script.txt
+++ b/ld_script.txt
@@ -49,7 +49,6 @@ SECTIONS {
         src/main_menu.o(.text);
         src/battle_controllers.o(.text);
         src/decompress.o(.text);
-        asm/decompress.o(.text);
         src/battle_bg.o(.text);
         src/battle_main.o(.text);
         src/battle_util.o(.text);
diff --git a/src/decompress.c b/src/decompress.c
index d6c52439f..9f8916d52 100644
--- a/src/decompress.c
+++ b/src/decompress.c
@@ -111,3 +111,147 @@ void Unused_LZDecompressWramIndirect(const void **src, void *dest)
 {
     LZ77UnCompWram(*src, dest);
 }
+
+void unref_sub_800D42C(int object_size, int object_count, unsigned char *src_tiles, unsigned char *dest_tiles)
+{
+	/*
+	  This function appears to emulate behaviour found in the GB(C) versions regarding how the Pokemon images
+	  are stitched together to be displayed on the battle screen.
+	  Given "compacted" tiles, an object count and a bounding box/object size, place the tiles in such a way
+	  that the result will have each object centered in a 8x8 tile canvas.
+	*/
+	int i, j, k, l;
+	unsigned char *src = src_tiles, *dest = dest_tiles;
+	unsigned char bottom_off;
+
+	if (object_size & 1)
+	{
+		// Object size is odd
+		bottom_off = (object_size >> 1) + 4;
+		for (l = 0; l < object_count; l++)
+		{
+			// Clear all unused rows of tiles plus the half-tile required due to centering
+			for (j = 0; j < 8-object_size; j++)
+			{
+				for (k = 0; k < 8; k++)
+				{
+					for (i = 0; i < 16; i++)
+					{
+						if (j % 2 == 0)
+						{
+							// Clear top half of top tile and bottom half of bottom tile when on even j
+							((dest+i) + (k << 5))[((j >> 1) << 8)] = 0;
+							((bottom_off << 8) + (dest+i) + (k << 5) + 16)[((j >> 1) << 8)] = 0;
+						}
+						else
+						{
+							// Clear bottom half of top tile and top half of tile following bottom tile when on odd j
+							((dest+i) + (k << 5) + 16)[((j >> 1) << 8)] = 0;
+							((bottom_off << 8) + (dest+i) + (k << 5) + 256)[((j >> 1) << 8)] = 0;
+						}
+					}
+				}
+			}
+
+			// Clear the columns to the left and right that wont be used completely
+			// Unlike the previous loops, this will clear the later used space as well
+			for (j = 0; j < 2; j++)
+			{
+				for (i = 0; i < 8; i++)
+				{
+					for (k = 0; k < 32; k++)
+					{
+						// Left side
+						((dest+k) + (i << 8))[(j << 5)] = 0;
+						// Right side
+						((dest+k) + (i << 8))[(j << 5)+192] = 0;
+					}
+				}
+			}
+
+			// Skip the top row and first tile on the second row for objects of size 5
+			if (object_size == 5) dest += 0x120;
+
+			// Copy tile data
+			for (j = 0; j < object_size; j++)
+			{
+				for (k = 0; k < object_size; k++)
+				{
+					for (i = 0; i < 4; i++)
+					{
+						// Offset the tile by +4px in both x and y directions
+						(dest + (i << 2))[18] = (src + (i << 2))[0];
+						(dest + (i << 2))[19] = (src + (i << 2))[1];
+						(dest + (i << 2))[48] = (src + (i << 2))[2];
+						(dest + (i << 2))[49] = (src + (i << 2))[3];
+
+						(dest + (i << 2))[258] = (src + (i << 2))[16];
+						(dest + (i << 2))[259] = (src + (i << 2))[17];
+						(dest + (i << 2))[288] = (src + (i << 2))[18];
+						(dest + (i << 2))[289] = (src + (i << 2))[19];
+					}
+					src += 32;
+					dest += 32;
+				}
+
+				// At the end of a row, skip enough tiles to get to the beginning of the next row
+				if (object_size == 7) dest += 0x20;
+				else if (object_size == 5) dest += 0x60;
+			}
+
+			// Skip remaining unused space to go to the beginning of the next object
+			if (object_size == 7) dest += 0x100;
+			else if (object_size == 5) dest += 0x1e0;
+		}
+	}
+	else
+	{
+		// Object size is even
+		for (i = 0; i < object_count; i++)
+		{
+			// For objects of size 6, the first and last row and column will be cleared
+			// While the remaining space will be filled with actual data
+			if (object_size == 6)
+			{
+				for (k = 0; k < 256; k++) {
+					*dest = 0;
+					dest++;
+				}
+			}
+
+			for (j = 0; j < object_size; j++)
+			{
+				if (object_size == 6)
+				{
+					for (k = 0; k < 32; k++) {
+						*dest = 0;
+						dest++;
+					}
+				}
+
+				// Copy tile data
+				for (k = 0; k < 32 * object_size; k++) {
+					*dest = *src;
+					src++;
+					dest++;
+				}
+
+				if (object_size == 6)
+				{
+					for (k = 0; k < 32; k++) {
+						*dest = 0;
+						dest++;
+					}
+				}
+			}
+
+			if (object_size == 6)
+			{
+				for (k = 0; k < 256; k++) {
+					*dest = 0;
+					dest++;
+				}
+			}
+		}
+	}
+}