97 lines
2.3 KiB
C++
97 lines
2.3 KiB
C++
#ifdef ICD2_CPP
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//convert linear pixel data { 0x00, 0x55, 0xaa, 0xff } to 2bpp planar tiledata
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void ICD2::render(const uint16 *source) {
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memset(lcd.output, 0x00, 320 * sizeof(uint16));
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for(unsigned y = 0; y < 8; y++) {
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for(unsigned x = 0; x < 160; x++) {
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unsigned pixel = *source++;
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unsigned addr = y * 2 + (x / 8 * 16);
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lcd.output[addr + 0] |= ((pixel & 1) >> 0) << (7 - (x & 7));
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lcd.output[addr + 1] |= ((pixel & 2) >> 1) << (7 - (x & 7));
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}
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}
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}
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uint8 ICD2::read(unsigned addr) {
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addr &= 0xffff;
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//LY counter
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if(addr == 0x6000) {
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r6000_ly = GameBoy::lcd.status.ly;
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r6000_row = lcd.row;
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return r6000_ly;
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}
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//command ready port
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if(addr == 0x6002) {
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bool data = packetsize > 0;
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if(data) {
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for(unsigned i = 0; i < 16; i++) r7000[i] = packet[0][i];
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packetsize--;
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for(unsigned i = 0; i < packetsize; i++) packet[i] = packet[i + 1];
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}
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return data;
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}
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//ICD2 revision
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if(addr == 0x600f) {
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return 0x21;
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}
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//command port
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if((addr & 0xfff0) == 0x7000) {
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return r7000[addr & 15];
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}
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//VRAM port
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if(addr == 0x7800) {
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uint8 data = lcd.output[r7800];
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r7800 = (r7800 + 1) % 320;
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return data;
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}
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return 0x00;
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}
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void ICD2::write(unsigned addr, uint8 data) {
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addr &= 0xffff;
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//VRAM port
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if(addr == 0x6001) {
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r6001 = data;
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r7800 = 0;
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unsigned offset = (r6000_row - (4 - (r6001 - (r6000_ly & 3)))) & 3;
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render(lcd.buffer + offset * 160 * 8);
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return;
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}
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//control port
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//d7: 0 = halt, 1 = reset
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//d5,d4: 0 = 1-player, 1 = 2-player, 2 = 4-player, 3 = ???
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//d1,d0: 0 = frequency divider (clock rate adjust)
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if(addr == 0x6003) {
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if((r6003 & 0x80) == 0x00 && (data & 0x80) == 0x80) {
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reset();
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}
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switch(data & 3) {
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case 0: frequency = cpu.frequency / 4; break; //fast (glitchy, even on real hardware)
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case 1: frequency = cpu.frequency / 5; break; //normal
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case 2: frequency = cpu.frequency / 7; break; //slow
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case 3: frequency = cpu.frequency / 9; break; //very slow
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}
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r6003 = data;
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return;
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}
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if(addr == 0x6004) { r6004 = data; return; } //joypad 1
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if(addr == 0x6005) { r6005 = data; return; } //joypad 2
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if(addr == 0x6006) { r6006 = data; return; } //joypad 3
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if(addr == 0x6007) { r6007 = data; return; } //joypad 4
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}
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#endif
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