mirror of https://github.com/mgba-emu/mgba.git
GBA BIOS: Clean up decompression routines and add writeback
This commit is contained in:
Jeffrey Pfau
parent
7059fcc257
commit
fb35a8b3f7
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@ -12,10 +12,10 @@
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const uint32_t GBA_BIOS_CHECKSUM = 0xBAAE187F;
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const uint32_t GBA_DS_BIOS_CHECKSUM = 0xBAAE1880;
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static void _unLz77(struct GBA* gba, uint32_t source, uint32_t dest, int width);
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static void _unHuffman(struct GBA* gba, uint32_t source, uint32_t dest);
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static void _unRl(struct GBA* gba, uint32_t source, uint32_t dest, int width);
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static void _unFilter(struct GBA* gba, uint32_t source, uint32_t dest, int inwidth, int outwidth);
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static void _unLz77(struct GBA* gba, int width);
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static void _unHuffman(struct GBA* gba);
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static void _unRl(struct GBA* gba, int width);
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static void _unFilter(struct GBA* gba, int inwidth, int outwidth);
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static void _RegisterRamReset(struct GBA* gba) {
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uint32_t registers = gba->cpu->gprs[0];
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@ -180,7 +180,7 @@ void GBASwi16(struct ARMCore* cpu, int immediate) {
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case REGION_WORKING_RAM:
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case REGION_WORKING_IRAM:
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case REGION_VRAM:
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_unLz77(gba, cpu->gprs[0], cpu->gprs[1], immediate == 0x11 ? 1 : 2);
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_unLz77(gba, immediate == 0x11 ? 1 : 2);
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break;
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}
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break;
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@ -194,7 +194,7 @@ void GBASwi16(struct ARMCore* cpu, int immediate) {
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case REGION_WORKING_RAM:
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case REGION_WORKING_IRAM:
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case REGION_VRAM:
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_unHuffman(gba, cpu->gprs[0], cpu->gprs[1]);
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_unHuffman(gba);
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break;
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}
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break;
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@ -209,7 +209,7 @@ void GBASwi16(struct ARMCore* cpu, int immediate) {
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case REGION_WORKING_RAM:
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case REGION_WORKING_IRAM:
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case REGION_VRAM:
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_unRl(gba, cpu->gprs[0], cpu->gprs[1], immediate == 0x14 ? 1 : 2);
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_unRl(gba, immediate == 0x14 ? 1 : 2);
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break;
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}
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break;
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@ -225,7 +225,7 @@ void GBASwi16(struct ARMCore* cpu, int immediate) {
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case REGION_WORKING_RAM:
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case REGION_WORKING_IRAM:
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case REGION_VRAM:
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_unFilter(gba, cpu->gprs[0], cpu->gprs[1], immediate == 0x18 ? 2 : 1, immediate == 0x16 ? 1 : 2);
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_unFilter(gba, immediate == 0x18 ? 2 : 1, immediate == 0x16 ? 1 : 2);
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break;
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}
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break;
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@ -250,13 +250,14 @@ uint32_t GBAChecksum(uint32_t* memory, size_t size) {
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return sum;
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}
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static void _unLz77(struct GBA* gba, uint32_t source, uint32_t dest, int width) {
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static void _unLz77(struct GBA* gba, int width) {
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struct ARMCore* cpu = gba->cpu;
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uint32_t source = cpu->gprs[0];
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uint32_t dest = cpu->gprs[1];
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int remaining = (cpu->memory.load32(cpu, source, 0) & 0xFFFFFF00) >> 8;
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// We assume the signature byte (0x10) is correct
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int blockheader = 0; // Some compilers warn if this isn't set, even though it's trivially provably always set
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uint32_t sPointer = source + 4;
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uint32_t dPointer = dest;
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source += 4;
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int blocksRemaining = 0;
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int block;
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uint32_t disp;
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@ -267,51 +268,54 @@ static void _unLz77(struct GBA* gba, uint32_t source, uint32_t dest, int width)
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if (blocksRemaining) {
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if (blockheader & 0x80) {
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// Compressed
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block = cpu->memory.loadU8(cpu, sPointer, 0) | (cpu->memory.loadU8(cpu, sPointer + 1, 0) << 8);
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sPointer += 2;
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disp = dPointer - (((block & 0x000F) << 8) | ((block & 0xFF00) >> 8)) - 1;
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block = cpu->memory.loadU8(cpu, source, 0) | (cpu->memory.loadU8(cpu, source + 1, 0) << 8);
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source += 2;
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disp = dest - (((block & 0x000F) << 8) | ((block & 0xFF00) >> 8)) - 1;
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bytes = ((block & 0x00F0) >> 4) + 3;
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while (bytes-- && remaining) {
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--remaining;
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byte = cpu->memory.loadU8(cpu, disp, 0);
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++disp;
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if (width == 2) {
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if (dPointer & 1) {
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if (dest & 1) {
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halfword |= byte << 8;
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cpu->memory.store16(cpu, dPointer ^ 1, halfword, 0);
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cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
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} else {
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halfword = byte;
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}
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} else {
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cpu->memory.store8(cpu, dPointer, byte, 0);
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cpu->memory.store8(cpu, dest, byte, 0);
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}
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++dPointer;
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++dest;
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}
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} else {
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// Uncompressed
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byte = cpu->memory.loadU8(cpu, sPointer, 0);
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++sPointer;
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byte = cpu->memory.loadU8(cpu, source, 0);
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++source;
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if (width == 2) {
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if (dPointer & 1) {
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if (dest & 1) {
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halfword |= byte << 8;
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cpu->memory.store16(cpu, dPointer ^ 1, halfword, 0);
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cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
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} else {
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halfword = byte;
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}
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} else {
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cpu->memory.store8(cpu, dPointer, byte, 0);
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cpu->memory.store8(cpu, dest, byte, 0);
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}
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++dPointer;
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++dest;
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--remaining;
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}
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blockheader <<= 1;
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--blocksRemaining;
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} else {
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blockheader = cpu->memory.loadU8(cpu, sPointer, 0);
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++sPointer;
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blockheader = cpu->memory.loadU8(cpu, source, 0);
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++source;
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blocksRemaining = 8;
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}
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}
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cpu->gprs[0] = source;
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cpu->gprs[1] = dest;
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cpu->gprs[3] = 0;
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}
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DECL_BITFIELD(HuffmanNode, uint8_t);
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@ -319,9 +323,10 @@ DECL_BITS(HuffmanNode, Offset, 0, 6);
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DECL_BIT(HuffmanNode, RTerm, 6);
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DECL_BIT(HuffmanNode, LTerm, 7);
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static void _unHuffman(struct GBA* gba, uint32_t source, uint32_t dest) {
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static void _unHuffman(struct GBA* gba) {
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struct ARMCore* cpu = gba->cpu;
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source = source & 0xFFFFFFFC;
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uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
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uint32_t dest = cpu->gprs[1];
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uint32_t header = cpu->memory.load32(cpu, source, 0);
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int remaining = header >> 8;
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int bits = header & 0xF;
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@ -335,8 +340,7 @@ static void _unHuffman(struct GBA* gba, uint32_t source, uint32_t dest) {
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int treesize = (cpu->memory.loadU8(cpu, source + 4, 0) << 1) + 1;
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int block = 0;
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uint32_t treeBase = source + 5;
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uint32_t sPointer = source + 5 + treesize;
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uint32_t dPointer = dest;
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source += 5 + treesize;
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uint32_t nPointer = treeBase;
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HuffmanNode node;
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int bitsRemaining;
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@ -344,8 +348,8 @@ static void _unHuffman(struct GBA* gba, uint32_t source, uint32_t dest) {
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int bitsSeen = 0;
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node = cpu->memory.load8(cpu, nPointer, 0);
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while (remaining > 0) {
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uint32_t bitstream = cpu->memory.load32(cpu, sPointer, 0);
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sPointer += 4;
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uint32_t bitstream = cpu->memory.load32(cpu, source, 0);
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source += 4;
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for (bitsRemaining = 32; bitsRemaining > 0 && remaining > 0; --bitsRemaining, bitstream <<= 1) {
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uint32_t next = (nPointer & ~1) + HuffmanNodeGetOffset(node) * 2 + 2;
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if (bitstream & 0x80000000) {
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@ -374,8 +378,8 @@ static void _unHuffman(struct GBA* gba, uint32_t source, uint32_t dest) {
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node = cpu->memory.load8(cpu, nPointer, 0);
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if (bitsSeen == 32) {
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bitsSeen = 0;
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cpu->memory.store32(cpu, dPointer, block, 0);
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dPointer += 4;
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cpu->memory.store32(cpu, dest, block, 0);
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dest += 4;
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remaining -= 4;
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block = 0;
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}
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@ -383,82 +387,89 @@ static void _unHuffman(struct GBA* gba, uint32_t source, uint32_t dest) {
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}
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if (padding) {
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cpu->memory.store32(cpu, dPointer, block, 0);
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cpu->memory.store32(cpu, dest, block, 0);
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}
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cpu->gprs[0] = source;
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cpu->gprs[1] = dest;
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}
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static void _unRl(struct GBA* gba, uint32_t source, uint32_t dest, int width) {
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static void _unRl(struct GBA* gba, int width) {
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struct ARMCore* cpu = gba->cpu;
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source = source & 0xFFFFFFFC;
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uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
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int remaining = (cpu->memory.load32(cpu, source, 0) & 0xFFFFFF00) >> 8;
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int padding = (4 - remaining) & 0x3;
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// We assume the signature byte (0x30) is correct
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int blockheader;
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int block;
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uint32_t sPointer = source + 4;
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uint32_t dPointer = dest;
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source += 4;
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uint32_t dest = cpu->gprs[1];
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int halfword = 0;
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while (remaining > 0) {
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blockheader = cpu->memory.loadU8(cpu, sPointer++, 0);
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blockheader = cpu->memory.loadU8(cpu, source, 0);
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++source;
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if (blockheader & 0x80) {
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// Compressed
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blockheader &= 0x7F;
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blockheader += 3;
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block = cpu->memory.loadU8(cpu, sPointer++, 0);
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block = cpu->memory.loadU8(cpu, source, 0);
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++source;
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while (blockheader-- && remaining) {
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--remaining;
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if (width == 2) {
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if (dPointer & 1) {
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if (dest & 1) {
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halfword |= block << 8;
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cpu->memory.store16(cpu, dPointer ^ 1, halfword, 0);
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cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
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} else {
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halfword = block;
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}
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} else {
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cpu->memory.store8(cpu, dPointer, block, 0);
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cpu->memory.store8(cpu, dest, block, 0);
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}
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++dPointer;
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++dest;
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}
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} else {
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// Uncompressed
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blockheader++;
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while (blockheader-- && remaining) {
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--remaining;
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int byte = cpu->memory.loadU8(cpu, sPointer, 0);
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++sPointer;
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int byte = cpu->memory.loadU8(cpu, source, 0);
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++source;
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if (width == 2) {
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if (dPointer & 1) {
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if (dest & 1) {
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halfword |= byte << 8;
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cpu->memory.store16(cpu, dPointer ^ 1, halfword, 0);
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cpu->memory.store16(cpu, dest ^ 1, halfword, 0);
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} else {
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halfword = byte;
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}
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} else {
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cpu->memory.store8(cpu, dPointer, byte, 0);
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cpu->memory.store8(cpu, dest, byte, 0);
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}
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++dPointer;
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++dest;
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}
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}
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}
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if (width == 2) {
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if (dPointer & 1) {
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if (dest & 1) {
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--padding;
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++dPointer;
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++dest;
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}
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for (; padding > 0; padding -= 2, dPointer += 2) {
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cpu->memory.store16(cpu, dPointer, 0, 0);
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for (; padding > 0; padding -= 2, dest += 2) {
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cpu->memory.store16(cpu, dest, 0, 0);
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}
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} else {
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while (padding--) {
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cpu->memory.store8(cpu, dPointer, 0, 0);
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++dPointer;
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cpu->memory.store8(cpu, dest, 0, 0);
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++dest;
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}
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}
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cpu->gprs[0] = source;
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cpu->gprs[1] = dest;
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}
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static void _unFilter(struct GBA* gba, uint32_t source, uint32_t dest, int inwidth, int outwidth) {
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static void _unFilter(struct GBA* gba, int inwidth, int outwidth) {
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struct ARMCore* cpu = gba->cpu;
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source = source & 0xFFFFFFFC;
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uint32_t source = cpu->gprs[0] & 0xFFFFFFFC;
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uint32_t dest = cpu->gprs[1];
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uint32_t header = cpu->memory.load32(cpu, source, 0);
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int remaining = header >> 8;
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// We assume the signature nybble (0x8) is correct
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@ -487,4 +498,6 @@ static void _unFilter(struct GBA* gba, uint32_t source, uint32_t dest, int inwid
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source += inwidth;
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remaining -= outwidth;
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}
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cpu->gprs[0] = source;
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cpu->gprs[1] = dest;
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}
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