Decompile unused function, as seen in ruby

1 files changed, 141 insertions, 340 deletions

diff --git a/src/decompress.c b/src/decompress.c
index 5e85e065f..819263eb4 100644
--- a/src/decompress.c
+++ b/src/decompress.c
@@ -114,347 +114,148 @@ void Unused_LZDecompressWramIndirect(const void **src, void *dest)
     LZ77UnCompWram(*src, dest);
 }
 
-// This one (unused) function is really challenging, won't even try to decompile it.
-NAKED
-void sub_803471C()
+void sub_803471C(int object_size, int object_count, unsigned char *src_tiles, unsigned char *dest_tiles)
 {
-    asm(".syntax unified\n\
-        push {r4-r7,lr}\n\
-    mov r7, r10\n\
-    mov r6, r9\n\
-    mov r5, r8\n\
-    push {r5-r7}\n\
-    sub sp, 0x24\n\
-    mov r9, r0\n\
-    str r1, [sp]\n\
-    str r2, [sp, 0x4]\n\
-    adds r5, r3, 0\n\
-    movs r0, 0x1\n\
-    mov r1, r9\n\
-    ands r0, r1\n\
-    cmp r0, 0\n\
-    bne _0803473C\n\
-    b _080348D4\n\
-_0803473C:\n\
-    asrs r0, r1, 1\n\
-    adds r0, 0x4\n\
-    lsls r0, 24\n\
-    lsrs r0, 24\n\
-    str r0, [sp, 0x8]\n\
-    movs r0, 0\n\
-    ldr r2, [sp]\n\
-    cmp r0, r2\n\
-    blt _08034750\n\
-    b _08034964\n\
-_08034750:\n\
-    movs r4, 0x8\n\
-    subs r1, r4, r1\n\
-    str r1, [sp, 0x10]\n\
-_08034756:\n\
-    movs r7, 0\n\
-    adds r0, 0x1\n\
-    str r0, [sp, 0x14]\n\
-    ldr r0, [sp, 0x10]\n\
-    cmp r7, r0\n\
-    bge _080347D2\n\
-    ldr r1, [sp, 0x8]\n\
-    lsls r1, 8\n\
-    str r1, [sp, 0x18]\n\
-    movs r2, 0\n\
-    mov r10, r2\n\
-    mov r0, r9\n\
-    movs r4, 0x8\n\
-    subs r0, r4, r0\n\
-    str r0, [sp, 0xC]\n\
-_08034774:\n\
-    movs r3, 0\n\
-    asrs r0, r7, 1\n\
-    adds r1, r7, 0\n\
-    movs r2, 0x1\n\
-    ands r1, r2\n\
-    str r1, [sp, 0x20]\n\
-    lsls r0, 8\n\
-    mov r8, r0\n\
-    mov r12, r5\n\
-_08034786:\n\
-    lsls r1, r3, 5\n\
-    ldr r4, [sp, 0x18]\n\
-    adds r0, r5, r4\n\
-    adds r0, r1\n\
-    mov r1, r8\n\
-    adds r2, r0, r1\n\
-    mov r1, r12\n\
-    add r1, r8\n\
-    movs r6, 0xF\n\
-_08034798:\n\
-    ldr r4, [sp, 0x20]\n\
-    cmp r4, 0\n\
-    bne _080347A8\n\
-    strb r4, [r1]\n\
-    add r4, sp, 0x20\n\
-    ldrb r4, [r4]\n\
-    strb r4, [r2, 0x10]\n\
-    b _080347B6\n\
-_080347A8:\n\
-    mov r0, r10\n\
-    strb r0, [r1, 0x10]\n\
-    movs r4, 0x80\n\
-    lsls r4, 1\n\
-    adds r4, r2, r4\n\
-    str r4, [sp, 0x1C]\n\
-    strb r0, [r4]\n\
-_080347B6:\n\
-    adds r2, 0x1\n\
-    adds r1, 0x1\n\
-    subs r6, 0x1\n\
-    cmp r6, 0\n\
-    bge _08034798\n\
-    movs r0, 0x20\n\
-    add r12, r0\n\
-    adds r3, 0x1\n\
-    cmp r3, 0x7\n\
-    ble _08034786\n\
-    adds r7, 0x1\n\
-    ldr r1, [sp, 0xC]\n\
-    cmp r7, r1\n\
-    blt _08034774\n\
-_080347D2:\n\
-    movs r7, 0\n\
-    movs r2, 0\n\
-_080347D6:\n\
-    movs r6, 0\n\
-    adds r4, r7, 0x1\n\
-    mov r8, r4\n\
-    lsls r4, r7, 5\n\
-_080347DE:\n\
-    adds r0, r6, 0x1\n\
-    mov r10, r0\n\
-    lsls r1, r6, 8\n\
-    adds r0, r1, 0\n\
-    adds r0, 0xC0\n\
-    adds r0, r5, r0\n\
-    adds r0, r4\n\
-    adds r1, r5, r1\n\
-    adds r1, r4\n\
-    movs r3, 0x1F\n\
-_080347F2:\n\
-    strb r2, [r1]\n\
-    strb r2, [r0]\n\
-    adds r0, 0x1\n\
-    adds r1, 0x1\n\
-    subs r3, 0x1\n\
-    cmp r3, 0\n\
-    bge _080347F2\n\
-    mov r6, r10\n\
-    cmp r6, 0x7\n\
-    ble _080347DE\n\
-    mov r7, r8\n\
-    cmp r7, 0x1\n\
-    ble _080347D6\n\
-    mov r1, r9\n\
-    cmp r1, 0x5\n\
-    bne _08034818\n\
-    movs r2, 0x90\n\
-    lsls r2, 1\n\
-    adds r5, r2\n\
-_08034818:\n\
-    movs r7, 0\n\
-    cmp r7, r9\n\
-    bge _080348AE\n\
-_0803481E:\n\
-    movs r3, 0\n\
-    adds r7, 0x1\n\
-    mov r8, r7\n\
-    cmp r3, r9\n\
-    bge _0803488E\n\
-_08034828:\n\
-    adds r3, 0x1\n\
-    mov r10, r3\n\
-    ldr r4, [sp, 0x4]\n\
-    adds r4, 0x20\n\
-    adds r7, r5, 0\n\
-    adds r7, 0x20\n\
-    movs r0, 0x12\n\
-    adds r0, r5\n\
-    mov r12, r0\n\
-    ldr r2, [sp, 0x4]\n\
-    adds r3, r5, 0\n\
-    movs r6, 0x3\n\
-_08034840:\n\
-    ldrb r0, [r2]\n\
-    mov r1, r12\n\
-    strb r0, [r1]\n\
-    ldrb r0, [r2, 0x1]\n\
-    strb r0, [r1, 0x1]\n\
-    ldrb r0, [r2, 0x2]\n\
-    strb r0, [r1, 0x1E]\n\
-    ldrb r0, [r2, 0x3]\n\
-    strb r0, [r1, 0x1F]\n\
-    movs r0, 0x81\n\
-    lsls r0, 1\n\
-    adds r1, r3, r0\n\
-    ldrb r0, [r2, 0x10]\n\
-    strb r0, [r1]\n\
-    ldr r0, =0x00000103\n\
-    adds r1, r3, r0\n\
-    ldrb r0, [r2, 0x11]\n\
-    strb r0, [r1]\n\
-    movs r0, 0x90\n\
-    lsls r0, 1\n\
-    adds r1, r3, r0\n\
-    ldrb r0, [r2, 0x12]\n\
-    strb r0, [r1]\n\
-    ldr r0, =0x00000121\n\
-    adds r1, r3, r0\n\
-    ldrb r0, [r2, 0x13]\n\
-    strb r0, [r1]\n\
-    movs r1, 0x4\n\
-    add r12, r1\n\
-    adds r2, 0x4\n\
-    adds r3, 0x4\n\
-    subs r6, 0x1\n\
-    cmp r6, 0\n\
-    bge _08034840\n\
-    str r4, [sp, 0x4]\n\
-    adds r5, r7, 0\n\
-    mov r3, r10\n\
-    cmp r3, r9\n\
-    blt _08034828\n\
-_0803488E:\n\
-    mov r2, r9\n\
-    cmp r2, 0x7\n\
-    bne _080348A0\n\
-    adds r5, 0x20\n\
-    b _080348A8\n\
-    .pool\n\
-_080348A0:\n\
-    mov r4, r9\n\
-    cmp r4, 0x5\n\
-    bne _080348A8\n\
-    adds r5, 0x60\n\
-_080348A8:\n\
-    mov r7, r8\n\
-    cmp r7, r9\n\
-    blt _0803481E\n\
-_080348AE:\n\
-    mov r0, r9\n\
-    cmp r0, 0x7\n\
-    bne _080348BC\n\
-    movs r1, 0x80\n\
-    lsls r1, 1\n\
-    adds r5, r1\n\
-    b _080348C8\n\
-_080348BC:\n\
-    mov r2, r9\n\
-    cmp r2, 0x5\n\
-    bne _080348C8\n\
-    movs r4, 0xF0\n\
-    lsls r4, 1\n\
-    adds r5, r4\n\
-_080348C8:\n\
-    ldr r0, [sp, 0x14]\n\
-    ldr r1, [sp]\n\
-    cmp r0, r1\n\
-    bge _080348D2\n\
-    b _08034756\n\
-_080348D2:\n\
-    b _08034964\n\
-_080348D4:\n\
-    movs r6, 0\n\
-    ldr r2, [sp]\n\
-    cmp r6, r2\n\
-    bge _08034964\n\
-_080348DC:\n\
-    adds r6, 0x1\n\
-    mov r10, r6\n\
-    mov r4, r9\n\
-    cmp r4, 0x6\n\
-    bne _080348F4\n\
-    movs r0, 0\n\
-    movs r3, 0xFF\n\
-_080348EA:\n\
-    strb r0, [r5]\n\
-    adds r5, 0x1\n\
-    subs r3, 0x1\n\
-    cmp r3, 0\n\
-    bge _080348EA\n\
-_080348F4:\n\
-    movs r7, 0\n\
-    cmp r7, r9\n\
-    bge _08034948\n\
-_080348FA:\n\
-    adds r7, 0x1\n\
-    mov r8, r7\n\
-    mov r1, r9\n\
-    lsls r0, r1, 5\n\
-    cmp r1, 0x6\n\
-    bne _08034914\n\
-    movs r1, 0\n\
-    movs r3, 0x1F\n\
-_0803490A:\n\
-    strb r1, [r5]\n\
-    adds r5, 0x1\n\
-    subs r3, 0x1\n\
-    cmp r3, 0\n\
-    bge _0803490A\n\
-_08034914:\n\
-    adds r1, r0, 0\n\
-    cmp r1, 0\n\
-    ble _0803492E\n\
-    adds r3, r1, 0\n\
-_0803491C:\n\
-    ldr r2, [sp, 0x4]\n\
-    ldrb r0, [r2]\n\
-    strb r0, [r5]\n\
-    adds r2, 0x1\n\
-    str r2, [sp, 0x4]\n\
-    adds r5, 0x1\n\
-    subs r3, 0x1\n\
-    cmp r3, 0\n\
-    bne _0803491C\n\
-_0803492E:\n\
-    mov r4, r9\n\
-    cmp r4, 0x6\n\
-    bne _08034942\n\
-    movs r0, 0\n\
-    movs r3, 0x1F\n\
-_08034938:\n\
-    strb r0, [r5]\n\
-    adds r5, 0x1\n\
-    subs r3, 0x1\n\
-    cmp r3, 0\n\
-    bge _08034938\n\
-_08034942:\n\
-    mov r7, r8\n\
-    cmp r7, r9\n\
-    blt _080348FA\n\
-_08034948:\n\
-    mov r0, r9\n\
-    cmp r0, 0x6\n\
-    bne _0803495C\n\
-    movs r0, 0\n\
-    movs r3, 0xFF\n\
-_08034952:\n\
-    strb r0, [r5]\n\
-    adds r5, 0x1\n\
-    subs r3, 0x1\n\
-    cmp r3, 0\n\
-    bge _08034952\n\
-_0803495C:\n\
-    mov r6, r10\n\
-    ldr r1, [sp]\n\
-    cmp r6, r1\n\
-    blt _080348DC\n\
-_08034964:\n\
-    add sp, 0x24\n\
-    pop {r3-r5}\n\
-    mov r8, r3\n\
-    mov r9, r4\n\
-    mov r10, r5\n\
-    pop {r4-r7}\n\
-    pop {r0}\n\
-    bx r0\n\
-        .syntax divided");
+	/*
+	  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++;
+				}
+			}
+		}
+	}
 }
 
 u32 GetDecompressedDataSize(const u32 *ptr)