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snes9x/spc7110dec.cpp

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/*****
* SPC7110 emulator - version 0.03 (2008-08-10)
* Copyright (c) 2008, byuu and neviksti
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* The software is provided "as is" and the author disclaims all warranties
* with regard to this software including all implied warranties of
* merchantibility and fitness, in no event shall the author be liable for
* any special, direct, indirect, or consequential damages or any damages
* whatsoever resulting from loss of use, data or profits, whether in an
* action of contract, negligence or other tortious action, arising out of
* or in connection with the use or performance of this software.
*****/
#ifdef _SPC7110EMU_CPP_
uint8 SPC7110Decomp::read() {
if(decomp_buffer_length == 0) {
//decompress at least (decomp_buffer_size / 2) bytes to the buffer
switch(decomp_mode) {
case 0: mode0(false); break;
case 1: mode1(false); break;
case 2: mode2(false); break;
default: return 0x00;
}
}
uint8 data = decomp_buffer[decomp_buffer_rdoffset++];
decomp_buffer_rdoffset &= decomp_buffer_size - 1;
decomp_buffer_length--;
return data;
}
void SPC7110Decomp::write(uint8 data) {
decomp_buffer[decomp_buffer_wroffset++] = data;
decomp_buffer_wroffset &= decomp_buffer_size - 1;
decomp_buffer_length++;
}
uint8 SPC7110Decomp::dataread() {
unsigned size = memory_cartrom_size() > 0x500000 ? memory_cartrom_size() - 0x200000 : memory_cartrom_size() - 0x100000;
while(decomp_offset >= size) decomp_offset -= size;
return memory_cartrom_read(0x100000 + decomp_offset++);
}
void SPC7110Decomp::init(unsigned mode, unsigned offset, unsigned index) {
decomp_mode = mode;
decomp_offset = offset;
decomp_buffer_rdoffset = 0;
decomp_buffer_wroffset = 0;
decomp_buffer_length = 0;
//reset context states
for(unsigned i = 0; i < 32; i++) {
context[i].index = 0;
context[i].invert = 0;
}
switch(decomp_mode) {
case 0: mode0(true); break;
case 1: mode1(true); break;
case 2: mode2(true); break;
}
//decompress up to requested output data index
while(index--) read();
}
//
void SPC7110Decomp::mode0(bool init) {
static uint8 val, in, span;
static int out, inverts, lps, in_count;
if(init == true) {
out = inverts = lps = 0;
span = 0xff;
val = dataread();
in = dataread();
in_count = 8;
return;
}
while(decomp_buffer_length < (decomp_buffer_size >> 1)) {
for(unsigned bit = 0; bit < 8; bit++) {
//get context
uint8 mask = (1 << (bit & 3)) - 1;
uint8 con = mask + ((inverts & mask) ^ (lps & mask));
if(bit > 3) con += 15;
//get prob and mps
unsigned prob = probability(con);
unsigned mps = (((out >> 15) & 1) ^ context[con].invert);
//get bit
unsigned flag_lps;
if(val <= span - prob) { //mps
span = span - prob;
out = (out << 1) + mps;
flag_lps = 0;
} else { //lps
val = val - (span - (prob - 1));
span = prob - 1;
out = (out << 1) + 1 - mps;
flag_lps = 1;
}
//renormalize
unsigned shift = 0;
while(span < 0x7f) {
shift++;
span = (span << 1) + 1;
val = (val << 1) + (in >> 7);
in <<= 1;
if(--in_count == 0) {
in = dataread();
in_count = 8;
}
}
//update processing info
lps = (lps << 1) + flag_lps;
inverts = (inverts << 1) + context[con].invert;
//update context state
if(flag_lps & toggle_invert(con)) context[con].invert ^= 1;
if(flag_lps) context[con].index = next_lps(con);
else if(shift) context[con].index = next_mps(con);
}
//save byte
write(out);
}
}
void SPC7110Decomp::mode1(bool init) {
static unsigned pixelorder[4], realorder[4];
static uint8 in, val, span;
static int out, inverts, lps, in_count;
if(init == true) {
for(unsigned i = 0; i < 4; i++) pixelorder[i] = i;
out = inverts = lps = 0;
span = 0xff;
val = dataread();
in = dataread();
in_count = 8;
return;
}
while(decomp_buffer_length < (decomp_buffer_size >> 1)) {
for(unsigned pixel = 0; pixel < 8; pixel++) {
//get first symbol context
unsigned a = ((out >> (1 * 2)) & 3);
unsigned b = ((out >> (7 * 2)) & 3);
unsigned c = ((out >> (8 * 2)) & 3);
unsigned con = (a == b) ? (b != c) : (b == c) ? 2 : 4 - (a == c);
//update pixel order
unsigned m, n;
for(m = 0; m < 4; m++) if(pixelorder[m] == a) break;
for(n = m; n > 0; n--) pixelorder[n] = pixelorder[n - 1];
pixelorder[0] = a;
//calculate the real pixel order
for(m = 0; m < 4; m++) realorder[m] = pixelorder[m];
//rotate reference pixel c value to top
for(m = 0; m < 4; m++) if(realorder[m] == c) break;
for(n = m; n > 0; n--) realorder[n] = realorder[n - 1];
realorder[0] = c;
//rotate reference pixel b value to top
for(m = 0; m < 4; m++) if(realorder[m] == b) break;
for(n = m; n > 0; n--) realorder[n] = realorder[n - 1];
realorder[0] = b;
//rotate reference pixel a value to top
for(m = 0; m < 4; m++) if(realorder[m] == a) break;
for(n = m; n > 0; n--) realorder[n] = realorder[n - 1];
realorder[0] = a;
//get 2 symbols
for(unsigned bit = 0; bit < 2; bit++) {
//get prob
unsigned prob = probability(con);
//get symbol
unsigned flag_lps;
if(val <= span - prob) { //mps
span = span - prob;
flag_lps = 0;
} else { //lps
val = val - (span - (prob - 1));
span = prob - 1;
flag_lps = 1;
}
//renormalize
unsigned shift = 0;
while(span < 0x7f) {
shift++;
span = (span << 1) + 1;
val = (val << 1) + (in >> 7);
in <<= 1;
if(--in_count == 0) {
in = dataread();
in_count = 8;
}
}
//update processing info
lps = (lps << 1) + flag_lps;
inverts = (inverts << 1) + context[con].invert;
//update context state
if(flag_lps & toggle_invert(con)) context[con].invert ^= 1;
if(flag_lps) context[con].index = next_lps(con);
else if(shift) context[con].index = next_mps(con);
//get next context
con = 5 + (con << 1) + ((lps ^ inverts) & 1);
}
//get pixel
b = realorder[(lps ^ inverts) & 3];
out = (out << 2) + b;
}
//turn pixel data into bitplanes
unsigned data = morton_2x8(out);
write(data >> 8);
write(data >> 0);
}
}
void SPC7110Decomp::mode2(bool init) {
static unsigned pixelorder[16], realorder[16];
static uint8 bitplanebuffer[16], buffer_index;
static uint8 in, val, span;
static int out0, out1, inverts, lps, in_count;
if(init == true) {
for(unsigned i = 0; i < 16; i++) pixelorder[i] = i;
buffer_index = 0;
out0 = out1 = inverts = lps = 0;
span = 0xff;
val = dataread();
in = dataread();
in_count = 8;
return;
}
while(decomp_buffer_length < (decomp_buffer_size >> 1)) {
for(unsigned pixel = 0; pixel < 8; pixel++) {
//get first symbol context
unsigned a = ((out0 >> (0 * 4)) & 15);
unsigned b = ((out0 >> (7 * 4)) & 15);
unsigned c = ((out1 >> (0 * 4)) & 15);
unsigned con = 0;
unsigned refcon = (a == b) ? (b != c) : (b == c) ? 2 : 4 - (a == c);
//update pixel order
unsigned m, n;
for(m = 0; m < 16; m++) if(pixelorder[m] == a) break;
for(n = m; n > 0; n--) pixelorder[n] = pixelorder[n - 1];
pixelorder[0] = a;
//calculate the real pixel order
for(m = 0; m < 16; m++) realorder[m] = pixelorder[m];
//rotate reference pixel c value to top
for(m = 0; m < 16; m++) if(realorder[m] == c) break;
for(n = m; n > 0; n--) realorder[n] = realorder[n - 1];
realorder[0] = c;
//rotate reference pixel b value to top
for(m = 0; m < 16; m++) if(realorder[m] == b) break;
for(n = m; n > 0; n--) realorder[n] = realorder[n - 1];
realorder[0] = b;
//rotate reference pixel a value to top
for(m = 0; m < 16; m++) if(realorder[m] == a) break;
for(n = m; n > 0; n--) realorder[n] = realorder[n - 1];
realorder[0] = a;
//get 4 symbols
for(unsigned bit = 0; bit < 4; bit++) {
//get prob
unsigned prob = probability(con);
//get symbol
unsigned flag_lps;
if(val <= span - prob) { //mps
span = span - prob;
flag_lps = 0;
} else { //lps
val = val - (span - (prob - 1));
span = prob - 1;
flag_lps = 1;
}
//renormalize
unsigned shift = 0;
while(span < 0x7f) {
shift++;
span = (span << 1) + 1;
val = (val << 1) + (in >> 7);
in <<= 1;
if(--in_count == 0) {
in = dataread();
in_count = 8;
}
}
//update processing info
lps = (lps << 1) + flag_lps;
unsigned invertbit = context[con].invert;
inverts = (inverts << 1) + invertbit;
//update context state
if(flag_lps & toggle_invert(con)) context[con].invert ^= 1;
if(flag_lps) context[con].index = next_lps(con);
else if(shift) context[con].index = next_mps(con);
//get next context
con = mode2_context_table[con][flag_lps ^ invertbit] + (con == 1 ? refcon : 0);
}
//get pixel
b = realorder[(lps ^ inverts) & 0x0f];
out1 = (out1 << 4) + ((out0 >> 28) & 0x0f);
out0 = (out0 << 4) + b;
}
//convert pixel data into bitplanes
unsigned data = morton_4x8(out0);
write(data >> 24);
write(data >> 16);
bitplanebuffer[buffer_index++] = data >> 8;
bitplanebuffer[buffer_index++] = data >> 0;
if(buffer_index == 16) {
for(unsigned i = 0; i < 16; i++) write(bitplanebuffer[i]);
buffer_index = 0;
}
}
}
//
const uint8 SPC7110Decomp::evolution_table[53][4] = {
//{ prob, nextlps, nextmps, toggle invert },
{ 0x5a, 1, 1, 1 },
{ 0x25, 6, 2, 0 },
{ 0x11, 8, 3, 0 },
{ 0x08, 10, 4, 0 },
{ 0x03, 12, 5, 0 },
{ 0x01, 15, 5, 0 },
{ 0x5a, 7, 7, 1 },
{ 0x3f, 19, 8, 0 },
{ 0x2c, 21, 9, 0 },
{ 0x20, 22, 10, 0 },
{ 0x17, 23, 11, 0 },
{ 0x11, 25, 12, 0 },
{ 0x0c, 26, 13, 0 },
{ 0x09, 28, 14, 0 },
{ 0x07, 29, 15, 0 },
{ 0x05, 31, 16, 0 },
{ 0x04, 32, 17, 0 },
{ 0x03, 34, 18, 0 },
{ 0x02, 35, 5, 0 },
{ 0x5a, 20, 20, 1 },
{ 0x48, 39, 21, 0 },
{ 0x3a, 40, 22, 0 },
{ 0x2e, 42, 23, 0 },
{ 0x26, 44, 24, 0 },
{ 0x1f, 45, 25, 0 },
{ 0x19, 46, 26, 0 },
{ 0x15, 25, 27, 0 },
{ 0x11, 26, 28, 0 },
{ 0x0e, 26, 29, 0 },
{ 0x0b, 27, 30, 0 },
{ 0x09, 28, 31, 0 },
{ 0x08, 29, 32, 0 },
{ 0x07, 30, 33, 0 },
{ 0x05, 31, 34, 0 },
{ 0x04, 33, 35, 0 },
{ 0x04, 33, 36, 0 },
{ 0x03, 34, 37, 0 },
{ 0x02, 35, 38, 0 },
{ 0x02, 36, 5, 0 },
{ 0x58, 39, 40, 1 },
{ 0x4d, 47, 41, 0 },
{ 0x43, 48, 42, 0 },
{ 0x3b, 49, 43, 0 },
{ 0x34, 50, 44, 0 },
{ 0x2e, 51, 45, 0 },
{ 0x29, 44, 46, 0 },
{ 0x25, 45, 24, 0 },
{ 0x56, 47, 48, 1 },
{ 0x4f, 47, 49, 0 },
{ 0x47, 48, 50, 0 },
{ 0x41, 49, 51, 0 },
{ 0x3c, 50, 52, 0 },
{ 0x37, 51, 43, 0 },
};
const uint8 SPC7110Decomp::mode2_context_table[32][2] = {
//{ next 0, next 1 },
{ 1, 2 },
{ 3, 8 },
{ 13, 14 },
{ 15, 16 },
{ 17, 18 },
{ 19, 20 },
{ 21, 22 },
{ 23, 24 },
{ 25, 26 },
{ 25, 26 },
{ 25, 26 },
{ 25, 26 },
{ 25, 26 },
{ 27, 28 },
{ 29, 30 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
{ 31, 31 },
};
uint8 SPC7110Decomp::probability (unsigned n) { return evolution_table[context[n].index][0]; }
uint8 SPC7110Decomp::next_lps (unsigned n) { return evolution_table[context[n].index][1]; }
uint8 SPC7110Decomp::next_mps (unsigned n) { return evolution_table[context[n].index][2]; }
bool SPC7110Decomp::toggle_invert(unsigned n) { return evolution_table[context[n].index][3]; }
unsigned SPC7110Decomp::morton_2x8(unsigned data) {
//reverse morton lookup: de-interleave two 8-bit values
//15, 13, 11, 9, 7, 5, 3, 1 -> 15- 8
//14, 12, 10, 8, 6, 4, 2, 0 -> 7- 0
return morton16[0][(data >> 0) & 255] + morton16[1][(data >> 8) & 255];
}
unsigned SPC7110Decomp::morton_4x8(unsigned data) {
//reverse morton lookup: de-interleave four 8-bit values
//31, 27, 23, 19, 15, 11, 7, 3 -> 31-24
//30, 26, 22, 18, 14, 10, 6, 2 -> 23-16
//29, 25, 21, 17, 13, 9, 5, 1 -> 15- 8
//28, 24, 20, 16, 12, 8, 4, 0 -> 7- 0
return morton32[0][(data >> 0) & 255] + morton32[1][(data >> 8) & 255]
+ morton32[2][(data >> 16) & 255] + morton32[3][(data >> 24) & 255];
}
//
void SPC7110Decomp::reset() {
//mode 3 is invalid; this is treated as a special case to always return 0x00
//set to mode 3 so that reading decomp port before starting first decomp will return 0x00
decomp_mode = 3;
decomp_buffer_rdoffset = 0;
decomp_buffer_wroffset = 0;
decomp_buffer_length = 0;
}
SPC7110Decomp::SPC7110Decomp() {
decomp_buffer = new uint8_t[decomp_buffer_size];
reset();
//initialize reverse morton lookup tables
for(unsigned i = 0; i < 256; i++) {
#define map(x, y) (((i >> x) & 1) << y)
//2x8-bit
morton16[1][i] = map(7, 15) + map(6, 7) + map(5, 14) + map(4, 6)
+ map(3, 13) + map(2, 5) + map(1, 12) + map(0, 4);
morton16[0][i] = map(7, 11) + map(6, 3) + map(5, 10) + map(4, 2)
+ map(3, 9) + map(2, 1) + map(1, 8) + map(0, 0);
//4x8-bit
morton32[3][i] = map(7, 31) + map(6, 23) + map(5, 15) + map(4, 7)
+ map(3, 30) + map(2, 22) + map(1, 14) + map(0, 6);
morton32[2][i] = map(7, 29) + map(6, 21) + map(5, 13) + map(4, 5)
+ map(3, 28) + map(2, 20) + map(1, 12) + map(0, 4);
morton32[1][i] = map(7, 27) + map(6, 19) + map(5, 11) + map(4, 3)
+ map(3, 26) + map(2, 18) + map(1, 10) + map(0, 2);
morton32[0][i] = map(7, 25) + map(6, 17) + map(5, 9) + map(4, 1)
+ map(3, 24) + map(2, 16) + map(1, 8) + map(0, 0);
#undef map
}
}
SPC7110Decomp::~SPC7110Decomp() {
delete[] decomp_buffer;
}
#endif
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