mirror of https://github.com/bsnes-emu/bsnes.git
145 lines
2.4 KiB
C++
145 lines
2.4 KiB
C++
auto MOS6502::algorithmADC(uint8 i) -> uint8 {
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int16 o;
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if(!BCD || !D) {
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o = A + i + C;
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V = ~(A ^ i) & (A ^ o) & 0x80;
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} else {
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idle();
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o = (A & 0x0f) + (i & 0x0f) + (C << 0);
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if(o > 0x09) o += 0x06;
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C = o > 0x0f;
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o = (A & 0xf0) + (i & 0xf0) + (C << 4) + (o & 0x0f);
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if(o > 0x9f) o += 0x60;
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}
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C = o.bit(8);
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Z = uint8(o) == 0;
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N = o.bit(7);
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return o;
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}
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auto MOS6502::algorithmAND(uint8 i) -> uint8 {
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uint8 o = A & i;
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Z = o == 0;
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N = o.bit(7);
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return o;
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}
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auto MOS6502::algorithmASL(uint8 i) -> uint8 {
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C = i.bit(7);
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i <<= 1;
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Z = i == 0;
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N = i.bit(7);
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return i;
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}
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auto MOS6502::algorithmBIT(uint8 i) -> uint8 {
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Z = (A & i) == 0;
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V = i.bit(6);
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N = i.bit(7);
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return A;
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}
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auto MOS6502::algorithmCMP(uint8 i) -> uint8 {
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uint9 o = A - i;
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C = !o.bit(8);
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Z = uint8(o) == 0;
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N = o.bit(7);
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return A;
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}
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auto MOS6502::algorithmCPX(uint8 i) -> uint8 {
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uint9 o = X - i;
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C = !o.bit(8);
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Z = uint8(o) == 0;
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N = o.bit(7);
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return X;
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}
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auto MOS6502::algorithmCPY(uint8 i) -> uint8 {
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uint9 o = Y - i;
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C = !o.bit(8);
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Z = uint8(o) == 0;
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N = o.bit(7);
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return Y;
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}
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auto MOS6502::algorithmDEC(uint8 i) -> uint8 {
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i--;
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Z = i == 0;
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N = i.bit(7);
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return i;
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}
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auto MOS6502::algorithmEOR(uint8 i) -> uint8 {
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uint8 o = A ^ i;
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Z = o == 0;
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N = o.bit(7);
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return o;
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}
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auto MOS6502::algorithmINC(uint8 i) -> uint8 {
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i++;
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Z = i == 0;
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N = i.bit(7);
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return i;
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}
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auto MOS6502::algorithmLD(uint8 i) -> uint8 {
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Z = i == 0;
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N = i.bit(7);
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return i;
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}
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auto MOS6502::algorithmLSR(uint8 i) -> uint8 {
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C = i.bit(0);
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i >>= 1;
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Z = i == 0;
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N = i.bit(7);
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return i;
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}
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auto MOS6502::algorithmORA(uint8 i) -> uint8 {
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uint8 o = A | i;
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Z = o == 0;
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N = o.bit(7);
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return o;
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}
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auto MOS6502::algorithmROL(uint8 i) -> uint8 {
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bool c = C;
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C = i.bit(7);
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i = i << 1 | c;
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Z = i == 0;
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N = i.bit(7);
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return i;
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}
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auto MOS6502::algorithmROR(uint8 i) -> uint8 {
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bool c = C;
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C = i.bit(0);
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i = c << 7 | i >> 1;
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Z = i == 0;
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N = i.bit(7);
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return i;
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}
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auto MOS6502::algorithmSBC(uint8 i) -> uint8 {
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i = ~i;
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int16 o;
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if(!BCD || !D) {
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o = A + i + C;
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V = ~(A ^ i) & (A ^ o) & 0x80;
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} else {
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idle();
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o = (A & 0x0f) + (i & 0x0f) + (C << 0);
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if(o <= 0x0f) o -= 0x06;
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C = o > 0x0f;
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o = (A & 0xf0) + (i & 0xf0) + (C << 4) + (o & 0x0f);
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if(o <= 0xff) o -= 0x60;
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}
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C = o.bit(8);
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Z = uint8(o) == 0;
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N = o.bit(7);
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return o;
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}
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