Begin disassembling bg.s

ld_script.txt

@@ -42,6 +42,7 @@ SECTIONS {
         src/malloc.o(.text);
         src/dma3_manager.o(.text);
         src/gpu_regs.o(.text);
+        src/bg.o(.text);
         asm/bg.o(.text);
         asm/blit.o(.text);
         src/window.o(.text);

src/bg.c

@@ -0,0 +1,533 @@
+#include "global.h"
+#include "dma3.h"
+
+#define DISPCNT_ALL_BG_AND_MODE_BITS    0x0F07
+#define SECONDARY_TILESET_BASE_TILE     0x4000
+#define SECONDARY_TILESET_BASE_BLOCK    0x800
+
+struct BgControl {
+    struct BgConfig {
+        u16 visible:1;
+        u16 unknown_1:1;
+        u16 screenSize:2;
+        u16 priority:2;
+        u16 mosaic:1;
+        u16 wraparound:1;
+        
+        u16 tilesBaseBlock:2;
+        u16 tileMapBaseBlock:5;
+        u16 paletteMode:1;
+        
+        u8 unknown_2;
+        u8 unknown_3;
+    } configs[4];
+    
+    u16 bgVisibilityAndMode;
+};
+
+struct BgTemplate {
+    u32 bg:2;
+    u32 tilesBaseBlock:2;
+    u32 tileMapBaseBlock:5;
+    u32 screenSize:2;
+    u32 paletteMode:1;
+    u32 priority:2;
+    u32 unk_1:10;
+};
+
+struct BgConfig2 {
+    u32 unk_1:10;
+    u32 unk_2:4;
+    u32 unk_3:18;
+    
+    u32 unk_4;
+    u32 unk_5;
+    u32 unk_6;
+};
+
+extern struct BgControl gUnknown_030008E0;    // gGpuBgConfigs
+extern struct BgConfig2 gUnknown_030008F8[4]; // gGpuBgConfigs2
+extern u32 gUnknown_03000938[4];
+extern u32 gUnneededFireRedVariable;
+extern struct BgConfig gZeroedBgControlStruct;
+extern bool32 IsInvalidBgDuplicate(u8 bg);
+
+void ResetBgControlStructs();
+
+extern void SetTextModeAndHideBgs();
+extern bool8 IsInvalidBg(u8 bg);
+extern void SetGpuReg(u8 regOffset, u16 value);
+extern u16 GetGpuReg(u8 regOffset);
+
+void ResetBgs(void)
+{
+    ResetBgControlStructs();
+    gUnknown_030008E0.bgVisibilityAndMode = 0;
+    SetTextModeAndHideBgs();
+}
+
+void SetBgModeInternal(u8 bgMode)
+{
+    gUnknown_030008E0.bgVisibilityAndMode &= 0xFFF8;
+    gUnknown_030008E0.bgVisibilityAndMode |= bgMode;
+}
+
+u8 GetBgMode(void)
+{
+    return gUnknown_030008E0.bgVisibilityAndMode & 0x7;
+}
+
+void ResetBgControlStructs(void)
+{
+    struct BgConfig* bgConfigs = &gUnknown_030008E0.configs[0];
+    struct BgConfig zeroedConfig = gZeroedBgControlStruct;
+    int i;
+    
+    for (i = 0; i < 4; i++)
+    {
+        bgConfigs[i] = zeroedConfig;
+    }
+}
+
+void Unused_ResetBgControlStruct(u8 bg)
+{
+    if (IsInvalidBg(bg) == FALSE)
+    {
+        gUnknown_030008E0.configs[bg] = gZeroedBgControlStruct;
+    }
+}
+
+void SetBgControlAttributes(u8 bg, u8 tilesBaseBlock, u8 tileMapBaseBlock, u8 screenSize, u8 paletteMode, u8 priority, u8 mosaic, u8 wraparound)
+{
+    if (IsInvalidBg(bg) == FALSE)
+    {
+        if (tilesBaseBlock != 0xFF)
+        {
+            gUnknown_030008E0.configs[bg].tilesBaseBlock = tilesBaseBlock & 0x3;
+        }
+        
+        if (tileMapBaseBlock != 0xFF)
+        {
+            gUnknown_030008E0.configs[bg].tileMapBaseBlock = tileMapBaseBlock & 0x1F;
+        }
+        
+        if (screenSize != 0xFF)
+        {
+            gUnknown_030008E0.configs[bg].screenSize = screenSize & 0x3;
+        }
+        
+        if (paletteMode != 0xFF)
+        {
+            gUnknown_030008E0.configs[bg].paletteMode = paletteMode;
+        }
+        
+        if (priority != 0xFF)
+        {
+            gUnknown_030008E0.configs[bg].priority = priority & 0x3;
+        }
+        
+        if (mosaic != 0xFF)
+        {
+            gUnknown_030008E0.configs[bg].mosaic = mosaic & 0x1;
+        }
+        
+        if (wraparound != 0xFF)
+        {
+            gUnknown_030008E0.configs[bg].wraparound = wraparound;
+        }
+        
+        gUnknown_030008E0.configs[bg].unknown_2 = 0;
+        gUnknown_030008E0.configs[bg].unknown_3 = 0;
+        
+        gUnknown_030008E0.configs[bg].visible = 1;
+    }
+}
+
+u16 GetBgControlAttribute(u8 bg, u8 attributeId)
+{
+    if (IsInvalidBg(bg) == FALSE && gUnknown_030008E0.configs[bg].visible != FALSE)
+    {
+        switch (attributeId)
+        {
+            case 1:
+                return gUnknown_030008E0.configs[bg].visible;
+            case 2:
+                return gUnknown_030008E0.configs[bg].tilesBaseBlock;
+            case 3:
+                return gUnknown_030008E0.configs[bg].tileMapBaseBlock;
+            case 4:
+                return gUnknown_030008E0.configs[bg].screenSize;
+            case 5:
+                return gUnknown_030008E0.configs[bg].paletteMode;
+            case 6:
+                return gUnknown_030008E0.configs[bg].priority;
+            case 7:
+                return gUnknown_030008E0.configs[bg].mosaic;
+            case 8:
+                return gUnknown_030008E0.configs[bg].wraparound;
+        }
+    }
+    
+    return 0xFF;
+}
+
+u8 LoadBgVram(u8 bg, void *src, u16 size, u16 destOffset, u8 mode)
+{
+    u16 offset;
+    s8 cursor;
+    
+    if (IsInvalidBg(bg) == FALSE && gUnknown_030008E0.configs[bg].visible != FALSE)
+    {
+        switch (mode)
+        {
+            case 0x1:
+                offset = gUnknown_030008E0.configs[bg].tilesBaseBlock * SECONDARY_TILESET_BASE_TILE;
+                break;
+            case 0x2:
+                offset = gUnknown_030008E0.configs[bg].tileMapBaseBlock * SECONDARY_TILESET_BASE_BLOCK;
+                break;
+            default:
+                cursor = -1;
+                goto end;
+        }
+        
+        offset = destOffset + offset;
+        
+        cursor = RequestDma3Copy(src, (void*)(offset + BG_VRAM), size, 0);
+        
+        if (cursor == -1)
+        {
+            return -1;
+        }
+    }
+    else
+    {
+       return -1;
+    }
+    
+end:
+    return cursor;
+}
+
+void ShowBgInternal(u8 bg)
+{
+    u16 value;
+    if (IsInvalidBg(bg) == FALSE && gUnknown_030008E0.configs[bg].visible != FALSE)
+    {
+        value = gUnknown_030008E0.configs[bg].priority |
+                (gUnknown_030008E0.configs[bg].tilesBaseBlock << 2) |
+                (gUnknown_030008E0.configs[bg].mosaic << 6) |
+                (gUnknown_030008E0.configs[bg].paletteMode << 7) |
+                (gUnknown_030008E0.configs[bg].tileMapBaseBlock << 8) |
+                (gUnknown_030008E0.configs[bg].wraparound << 13) |
+                (gUnknown_030008E0.configs[bg].screenSize << 14);
+        
+        SetGpuReg((bg << 1) + 0x8, value);
+        
+        gUnknown_030008E0.bgVisibilityAndMode |= 1 << (bg + 8);
+        gUnknown_030008E0.bgVisibilityAndMode &= DISPCNT_ALL_BG_AND_MODE_BITS;
+    }
+}
+
+void HideBgInternal(u8 bg)
+{
+    if (IsInvalidBg(bg) == FALSE)
+    {
+        gUnknown_030008E0.bgVisibilityAndMode &= ~(1 << (bg + 8));
+        gUnknown_030008E0.bgVisibilityAndMode &= DISPCNT_ALL_BG_AND_MODE_BITS;
+    }
+}
+
+void SyncBgVisibilityAndMode()
+{
+    SetGpuReg(0, (GetGpuReg(0) & ~DISPCNT_ALL_BG_AND_MODE_BITS) | gUnknown_030008E0.bgVisibilityAndMode);
+}
+
+void SetTextModeAndHideBgs()
+{
+    SetGpuReg(0, GetGpuReg(0) & ~DISPCNT_ALL_BG_AND_MODE_BITS);
+}
+
+void SetBgAffineInternal(u8 bg, u32 srcCenterX, u32 srcCenterY, u16 dispCenterX, u16 dispCenterY, u16 scaleX, u16 scaleY, u16 rotationAngle)
+{
+    struct BgAffineSrcData src;
+    struct BgAffineDstData dest;
+    
+    switch (gUnknown_030008E0.bgVisibilityAndMode & 0x7)
+    {
+        case 1:
+            if (bg != 2)
+                return;
+            break;
+        case 2:
+            if (bg < 2 || bg > 3)
+                return;
+            break;
+        case 0:
+        default:
+            return;
+    }
+    
+    src.texX = srcCenterX;
+    src.texY = srcCenterY;
+    src.scrX = dispCenterX;
+    src.scrY = dispCenterY;
+    src.sx = scaleX;
+    src.sy = scaleY;
+    src.alpha = rotationAngle;
+    
+    BgAffineSet(&src, &dest, 1);
+
+    SetGpuReg(REG_OFFSET_BG2PA, dest.pa);
+    SetGpuReg(REG_OFFSET_BG2PB, dest.pb);
+    SetGpuReg(REG_OFFSET_BG2PC, dest.pc);
+    SetGpuReg(REG_OFFSET_BG2PD, dest.pd);
+    SetGpuReg(REG_OFFSET_BG2PA, dest.pa);
+    SetGpuReg(REG_OFFSET_BG2X_L, (s16)(dest.dx));
+    SetGpuReg(REG_OFFSET_BG2X_H, (s16)(dest.dx >> 16));
+    SetGpuReg(REG_OFFSET_BG2Y_L, (s16)(dest.dy));
+    SetGpuReg(REG_OFFSET_BG2Y_H, (s16)(dest.dy >> 16));
+}
+
+bool8 IsInvalidBg(u8 bg)
+{
+    if (bg > 3)
+        return TRUE;
+    return FALSE;
+}
+
+int DummiedOutFireRedLeafGreenTileAllocFunc(int a1, int a2, int a3, int a4)
+{
+    return 0;
+}
+
+void ResetBgsAndClearDma3BusyFlags(u32 leftoverFireRedLeafGreenVariable)
+{
+    int i;
+    ResetBgs();
+    
+    for (i = 0; i < 4; i++)
+    {
+        gUnknown_03000938[i] = 0;
+    }
+    
+    gUnneededFireRedVariable = leftoverFireRedLeafGreenVariable;
+}
+
+void InitBgsFromTemplates(u8 bgMode, struct BgTemplate *templates, u8 numTemplates)
+{
+    int i;
+    u8 bg;
+    
+    SetBgModeInternal(bgMode);
+    ResetBgControlStructs();
+
+    for (i = 0; i < numTemplates; i++)
+    {
+        bg = templates[i].bg;
+        if (bg < 4) {
+            SetBgControlAttributes(bg,
+                                   templates[i].tilesBaseBlock,
+                                   templates[i].tileMapBaseBlock,
+                                   templates[i].screenSize,
+                                   templates[i].paletteMode,
+                                   templates[i].priority,
+                                   0,
+                                   0);
+            
+            gUnknown_030008F8[bg].unk_1 = templates[i].unk_1;
+            gUnknown_030008F8[bg].unk_2 = 0;
+            gUnknown_030008F8[bg].unk_3 = 0;
+            
+            gUnknown_030008F8[bg].unk_4 = 0;
+            gUnknown_030008F8[bg].unk_5 = 0;
+            gUnknown_030008F8[bg].unk_6 = 0;
+        }
+    }
+}
+
+void InitBgFromTemplate(struct BgTemplate *template)
+{
+    u8 bg = template->bg;
+    
+    if (bg < 4)
+    {
+        SetBgControlAttributes(bg,
+                               template->tilesBaseBlock,
+                               template->tileMapBaseBlock,
+                               template->screenSize,
+                               template->paletteMode,
+                               template->priority,
+                               0,
+                               0);
+        
+        gUnknown_030008F8[bg].unk_1 = template->unk_1;
+        gUnknown_030008F8[bg].unk_2 = 0;
+        gUnknown_030008F8[bg].unk_3 = 0;
+        
+        gUnknown_030008F8[bg].unk_4 = 0;
+        gUnknown_030008F8[bg].unk_5 = 0;
+        gUnknown_030008F8[bg].unk_6 = 0;
+    }
+}
+
+void SetBgMode(u8 bgMode)
+{
+    SetBgModeInternal(bgMode);
+}
+
+u16 LoadBgTiles(u8 bg, void *src, u16 size, u16 destOffset)
+{
+    u16 unk;
+    u8 cursor;
+    
+    if (GetBgControlAttribute(bg, 5) == 0)
+    {
+        unk = (gUnknown_030008F8[bg].unk_1 + destOffset) * 0x20;
+    }
+    else
+    {
+        unk = (gUnknown_030008F8[bg].unk_1 + destOffset) * 0x40;
+    }
+    
+    cursor = LoadBgVram(bg, src, size, unk, DISPCNT_MODE_1);
+    
+    if (cursor == 0xFF)
+    {
+        return -1;
+    }
+    
+    gUnknown_03000938[cursor >> 5] |= (1 << (cursor & 0x1F));
+    
+    if (gUnneededFireRedVariable == 1)
+    {
+        DummiedOutFireRedLeafGreenTileAllocFunc(bg, unk >> 5, size >> 5, 1);
+    }
+    
+    return cursor;
+}
+
+u16 LoadBgTilemap(u8 bg, void *src, u16 size, u16 destOffset)
+{
+    u8 cursor;
+    
+    cursor = LoadBgVram(bg, src, size, destOffset * 2, DISPCNT_MODE_2);
+    
+    if (cursor == 0xFF)
+    {
+        return -1;
+    }
+    
+    gUnknown_03000938[cursor >> 5] |= (1 << (cursor & 0x1F));
+    
+    return cursor;
+}
+
+#ifdef NONMATCHING
+u16 Unused_LoadBgPalette(u8 bg, void *src, u16 size, u16 destOffset)
+{
+    u16 unk_1;
+    s8 cursor;
+    int cursor2;
+    u32* ptr;
+    
+    if (IsInvalidBgDuplicate(bg) == FALSE)
+    {
+        unk_1 = (gUnknown_030008F8[bg].unk_2 * 0x20) + (destOffset * 2);
+        cursor = RequestDma3Copy(src, (void*)(unk_1 + BG_PLTT), size, 0);
+        cursor2 = cursor;
+    }
+    else
+    {
+        return -1;
+    }
+    
+    if (cursor == -1)
+    {
+        return -1;
+    }
+
+    ptr = gUnknown_03000938;
+    
+    if (cursor < 0)
+    {
+        cursor2 += 0x1F;
+    }
+    
+    cursor2 >>= 5;
+    
+    ptr[cursor2] |= (1 << (s8)(cursor - (cursor2 << 5)));
+
+    return (u8)cursor;
+}
+#else
+__attribute__((naked))
+u8 Unused_LoadBgPalette(u8 bg, void *src, u16 size, u16 destOffset)
+{
+    asm("push {r4-r7,lr}\n\
+    add r7, r1, #0\n\
+    lsl r0, #24\n\
+    lsr r4, r0, #24\n\
+    lsl r2, #16\n\
+    lsr r6, r2, #16\n\
+    lsl r3, #16\n\
+    lsr r5, r3, #16\n\
+    add r0, r4, #0\n\
+    bl IsInvalidBgDuplicate\n\
+    cmp r0, #0\n\
+    bne _08001A98\n\
+    ldr r1, =gUnknown_030008F8\n\
+    lsl r0, r4, #4\n\
+    add r0, r1\n\
+    ldrb r1, [r0, #0x1]\n\
+    lsl r1, #26\n\
+    lsr r1, #28\n\
+    lsl r1, #5\n\
+    lsl r0, r5, #1\n\
+    add r1, r0\n\
+    lsl r1, #16\n\
+    lsr r1, #16\n\
+    mov r0, #0xA0\n\
+    lsl r0, #19\n\
+    add r1, r0\n\
+    add r0, r7, #0\n\
+    add r2, r6, #0\n\
+    mov r3, #0\n\
+    bl RequestDma3Copy\n\
+    lsl r3, r0, #24\n\
+    asr r1, r3, #24\n\
+    mov r0, #0x1\n\
+    neg r0, r0\n\
+    cmp r1, r0\n\
+    bne _08001AA4\n\
+_08001A98:\n\
+    ldr r0, =0x0000ffff\n\
+    b _08001AC8\n\
+    .pool\n\
+_08001AA4:\n\
+    ldr r4, =gUnknown_03000938\n\
+    add r0, r1, #0\n\
+    cmp r1, #0\n\
+    bge _08001AAE\n\
+    add r0, #0x1F\n\
+_08001AAE:\n\
+    asr r0, #5\n\
+    lsl r2, r0, #2\n\
+    add r2, r4\n\
+    lsl r0, #5\n\
+    sub r0, r1, r0\n\
+    lsl r0, #24\n\
+    asr r0, #24\n\
+    mov r1, #0x1\n\
+    lsl r1, r0\n\
+    ldr r0, [r2]\n\
+    orr r0, r1\n\
+    str r0, [r2]\n\
+    lsr r0, r3, #24\n\
+_08001AC8:\n\
+    pop {r4-r7}\n\
+    pop {r1}\n\
+    bx r1\n\
+    .pool");
+}
+#endif // NONMATCHING