mirror of https://github.com/bsnes-emu/bsnes.git
Update to v089r11 release.
byuu says: Changelog: - SPC7110 $480b (and its settings in $4805-6 + $4807) is now fully emulated - decompressor restructured and commented accordingly The final parts remaining for the SPC7110 core, all within the decompression engine: - need to detect when 15+ input bytes are read for one output byte and simulate a crash somehow (don't have to perfectly simulate corrupted data stream) - need to emulate time required to decompress data (doesn't have to be perfect, just something other than instantaneous) - need to determine what $480c status flags d6-d0 are for, as best we can anyway
This commit is contained in:
Tim Allen
parent
4545e7c62d
commit
ec8350794a
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@ -3,7 +3,7 @@
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namespace Emulator {
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static const char Name[] = "bsnes";
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static const char Version[] = "089.10";
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static const char Version[] = "089.11";
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static const char Author[] = "byuu";
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static const char License[] = "GPLv3";
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}
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@ -16,68 +16,42 @@ void SPC7110::dcu_begin_transfer() {
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add_clocks(20);
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decompressor->initialize(dcu_mode, dcu_addr);
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decompressor->decode();
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if(r480b & 2) {
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unsigned seek = (r4805 | r4806 << 8) << dcu_mode;
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add_clocks(seek);
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while(seek--) decompressor->output();
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}
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unsigned seek = r480b & 2 ? r4805 | r4806 << 8 : 0;
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while(seek--) decompressor->decode();
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r480c |= 0x80;
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dcu_offset = 0;
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}
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uint8 SPC7110::dcu_read() {
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if((r480c & 0x80) == 0) return 0x00;
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return decompressor->output();
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}
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/*
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unsigned tilesize = 8 << dcu_mode;
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if(dcu_sp == 0) {
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unsigned tiles = r480b & 1 ? r4807 : 1;
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for(unsigned tile = 0; tile < tiles; tile++) {
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dcu_dp = tile * tilesize;
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switch(dcu_mode) {
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case 0: decompress_1bpp(); deinterleave_1bpp(tiles); break;
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case 1: decompress_2bpp(); deinterleave_2bpp(tiles); break;
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case 2: decompress_4bpp(); deinterleave_4bpp(tiles); break;
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case 3: return 0x00;
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if(dcu_offset == 0) {
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for(unsigned row = 0; row < 8; row++) {
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switch(decompressor->bpp) {
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case 1:
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dcu_tile[row] = decompressor->result;
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break;
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case 2:
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dcu_tile[row * 2 + 0] = decompressor->result >> 0;
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dcu_tile[row * 2 + 1] = decompressor->result >> 8;
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break;
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case 4:
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dcu_tile[row * 2 + 0] = decompressor->result >> 0;
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dcu_tile[row * 2 + 1] = decompressor->result >> 8;
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dcu_tile[row * 2 + 16] = decompressor->result >> 16;
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dcu_tile[row * 2 + 17] = decompressor->result >> 24;
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break;
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}
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unsigned seek = r480b & 1 ? r4807 : 1;
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while(seek--) decompressor->decode();
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}
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}
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uint8 data = dcu_output[dcu_sp++];
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dcu_sp &= tilesize - 1;
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uint8 data = dcu_tile[dcu_offset++];
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dcu_offset &= 8 * decompressor->bpp - 1;
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return data;
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*/
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/*
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void SPC7110::deinterleave_1bpp(unsigned length) {
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uint8 *target = dcu_output, *source = dcu_tiledata;
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for(unsigned row = 0, sp = 0; row < 8; row++) {
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target[row] = source[sp];
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sp += length;
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}
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}
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void SPC7110::deinterleave_2bpp(unsigned length) {
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uint8 *target = dcu_output, *source = dcu_tiledata;
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for(unsigned row = 0, sp = 0; row < 8; row++) {
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target[row * 2 + 0] = source[sp + 0];
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target[row * 2 + 1] = source[sp + 1];
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sp += 2 * length;
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}
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}
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void SPC7110::deinterleave_4bpp(unsigned length) {
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uint8 *target = dcu_output, *source = dcu_tiledata;
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for(unsigned row = 0, sp = 0; row < 8; row++) {
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target[row * 2 + 0] = source[sp + 0];
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target[row * 2 + 1] = source[sp + 1];
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target[row * 2 + 16] = source[sp + 16];
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target[row * 2 + 17] = source[sp + 17];
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sp = sp + 2 * length + 16 * ((sp + 2 * length) / 16 - sp / 16);
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}
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}
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*/
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@ -7,17 +7,12 @@ struct Decompressor {
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Decompressor(SPC7110 &spc7110) : spc7110(spc7110) {}
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uint8 input() {
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uint8 read() {
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return spc7110.datarom_read(offset++);
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}
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uint8 output() {
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if(cursor == 0) decompress();
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uint8 data = tile[cursor++];
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cursor &= 8 * bpp - 1;
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return data;
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}
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//inverse morton code transform: unpack big-endian packed pixels
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//returns odd bits in lower half; even bits in upper half
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uint32 deinterleave(uint64 data, unsigned bits) {
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data = data & (1ull << bits) - 1;
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data = 0x5555555555555555ull & (data << bits | data >> 1);
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@ -28,6 +23,7 @@ struct Decompressor {
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return data | data >> 16;
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}
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//extract a nibble and move it to the low four bits
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uint64 moveToFront(uint64 list, unsigned nibble) {
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for(uint64 n = 0, mask = ~15; n < 64; n += 4, mask <<= 4) {
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if((list >> n & 15) != nibble) continue;
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@ -38,21 +34,18 @@ struct Decompressor {
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void initialize(unsigned mode, unsigned origin) {
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for(auto &root : context) for(auto &node : root) node = {0, 0};
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base = 0;
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range = Max + 1;
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bpp = 1 << mode;
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offset = origin;
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cursor = 0;
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bits = 8;
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read = input();
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read = read << 8 | input();
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write = 0;
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range = Max + 1;
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input = read();
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input = input << 8 | read();
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output = 0;
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pixels = 0;
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colormap = 0xfedcba9876543210ull;
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}
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void decompress() {
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for(unsigned row = 0; row < 8; row++) {
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void decode() {
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for(unsigned pixel = 0; pixel < 8; pixel++) {
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uint64 map = colormap;
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unsigned diff = 0;
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@ -64,10 +57,10 @@ struct Decompressor {
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if(pa != pb || pb != pc) {
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unsigned match = pa ^ pb ^ pc;
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diff = 4;
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if((match ^ pc) == 0) diff = 3;
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if((match ^ pb) == 0) diff = 2;
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if((match ^ pa) == 0) diff = 1;
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diff = 4; //no match; all pixels differ
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if((match ^ pc) == 0) diff = 3; //a == b; pixel c differs
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if((match ^ pb) == 0) diff = 2; //c == a; pixel b differs
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if((match ^ pa) == 0) diff = 1; //b == c; pixel a differs
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}
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colormap = moveToFront(colormap, pa);
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@ -79,7 +72,7 @@ struct Decompressor {
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for(unsigned plane = 0; plane < bpp; plane++) {
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unsigned bit = bpp > 1 ? 1 << plane : 1 << (pixel & 3);
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unsigned history = bit - 1 & write;
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unsigned history = bit - 1 & output;
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unsigned set = 0;
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if(bpp == 1) set = pixel >= 4;
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@ -89,58 +82,41 @@ struct Decompressor {
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auto &ctx = context[set][bit + history - 1];
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auto &model = evolution[ctx.prediction];
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uint8 lps_offset = range - model.probability;
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bool symbol = read >= (lps_offset << 8);
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bool symbol = input >= (lps_offset << 8); //test only the MSB
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write = write << 1 | (symbol ^ ctx.swap);
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output = output << 1 | (symbol ^ ctx.swap);
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if(symbol == MPS) {
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range = lps_offset;
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} else {
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range -= lps_offset;
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read -= lps_offset << 8;
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base += lps_offset;
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if(symbol == MPS) { //[0 ... range-p]
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range = lps_offset; //range = range-p
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} else { //[range-p+1 ... range]
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range -= lps_offset; //range = p-1, with p < 0.75
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input -= lps_offset << 8; //therefore, always rescale
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}
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while(range <= Max / 2) {
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while(range <= Max / 2) { //scale back into [0.75 ... 1.5]
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ctx.prediction = model.next[symbol];
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range <<= 1;
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read <<= 1;
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base <<= 1;
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input <<= 1;
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if(--bits == 0) {
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bits = 8;
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read += input();
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input += read();
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}
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}
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if(symbol == LPS && model.probability > Half) ctx.swap ^= 1;
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}
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unsigned index = write & (1 << bpp) - 1;
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unsigned index = output & (1 << bpp) - 1;
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if(bpp == 1) index ^= pixels >> 15 & 1;
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pixels = pixels << bpp | (map >> 4 * index & 15);
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}
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if(bpp == 1) {
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tile[row] = pixels;
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}
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if(bpp == 2) {
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uint32 slice = deinterleave(pixels, 16);
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tile[row * 2 + 0] = slice >> 0;
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tile[row * 2 + 1] = slice >> 8;
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}
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if(bpp == 4) {
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uint32 slice = deinterleave(deinterleave(pixels, 32), 32);
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tile[row * 2 + 0x00] = slice >> 0;
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tile[row * 2 + 0x01] = slice >> 8;
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tile[row * 2 + 0x10] = slice >> 16;
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tile[row * 2 + 0x11] = slice >> 24;
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}
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}
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if(bpp == 1) result = pixels;
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if(bpp == 2) result = deinterleave(pixels, 16);
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if(bpp == 4) result = deinterleave(deinterleave(pixels, 32), 32);
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}
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void serialize(serializer &s) {
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@ -151,44 +127,40 @@ struct Decompressor {
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}
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}
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s.integer(base);
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s.integer(range);
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s.integer(bpp);
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s.integer(offset);
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s.integer(cursor);
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s.integer(bits);
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s.integer(read);
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s.integer(write);
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s.integer(range);
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s.integer(input);
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s.integer(output);
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s.integer(pixels);
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s.integer(colormap);
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s.array(tile);
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s.integer(result);
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}
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enum : unsigned { MPS = 0, LPS = 1 };
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enum : unsigned { One = 0xaa, Half = 0x55, Max = 0xff };
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struct ModelState {
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uint8 probability;
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uint8 next[2];
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uint8 probability; //of the more probable symbol (MPS)
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uint8 next[2]; //next state after output {MPS, LPS}
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};
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static ModelState evolution[53];
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struct Context {
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uint8 prediction;
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uint8 swap;
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} context[5][15];
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uint8 prediction; //current model state
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uint8 swap; //if 1, exchange the role of MPS and LPS
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} context[5][15]; //not all 75 contexts exists; this simplifies the code
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uint8 base;
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uint16 range;
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unsigned bpp;
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unsigned offset;
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unsigned cursor;
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unsigned bits;
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uint16 read;
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uint8 write;
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unsigned bpp; //bits per pixel (1bpp = 1; 2bpp = 2; 4bpp = 4)
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unsigned offset; //SPC7110 data ROM read offset
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unsigned bits; //bits remaining in input
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uint16 range; //arithmetic range: technically 8-bits, but Max+1 = 256
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uint16 input; //input data from SPC7110 data ROM
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uint8 output;
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uint64 pixels;
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uint64 colormap;
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uint8 tile[32];
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uint64 colormap; //most recently used list
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uint32 result; //decompressed word after calling decode()
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};
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Decompressor::ModelState Decompressor::evolution[53] = {
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@ -16,6 +16,8 @@ void SPC7110::serialize(serializer &s) {
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s.integer(dcu_pending);
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s.integer(dcu_mode);
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s.integer(dcu_addr);
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s.integer(dcu_offset);
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s.array(dcu_tile);
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decompressor->serialize(s);
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s.integer(r4810);
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@ -68,9 +68,9 @@ private:
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uint8 r4802; //compression table B1
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uint7 r4803; //compression table B2
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uint8 r4804; //compression table index
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uint8 r4805; //decompression buffer index B0
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uint8 r4806; //decompression buffer index B1
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uint8 r4807; //deinterleave length
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uint8 r4805; //adjust length B0
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uint8 r4806; //adjust length B1
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uint8 r4807; //stride length
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uint8 r4809; //compression counter B0
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uint8 r480a; //compression counter B1
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uint8 r480b; //decompression settings
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@ -79,6 +79,8 @@ private:
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bool dcu_pending;
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uint2 dcu_mode;
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uint23 dcu_addr;
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unsigned dcu_offset;
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uint8 dcu_tile[32];
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Decompressor *decompressor;
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//==============
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