mirror of
https://github.com/bsnes-emu/bsnes.git
synced 2025-02-24 07:02:27 +01:00
ea02f1e36a
byuu says: This WIP scores 448/920 tests passed. Gave a shot at ROM prefetch that failed miserably (ranged from 409 to 494 tests passed. Nowhere near where it would be if it were implemented correctly.) Three remaining issues: - ROM prefetch - DMA timing - timers (I suspect it's a 3-clock delay in starting, not a 3-clock into the future affair) Probably only going to be able to get the timers working without heroic amounts of effort. MUL timing is fixed to use idle cycles. STMIA is fixed to set sequential at the right moments. DMA priority support is added, so DMA 0 can interrupt DMA 1 mid-transfer. In other news ... I'm calling gtk_widget_destroy on the GtkWindow now, so hopefully those Window_configure issues go away. I realize I was leaking Display* handles in the X-video driver while I was looking at it, so I fixed those. I added DT_NOPREFIX so the Windows ListView will show & characters correctly now.
104 lines
3.6 KiB
C++
104 lines
3.6 KiB
C++
auto ARM::condition(uint4 condition) -> bool {
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switch(condition) {
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case 0: return cpsr().z == 1; //EQ (equal)
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case 1: return cpsr().z == 0; //NE (not equal)
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case 2: return cpsr().c == 1; //CS (carry set)
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case 3: return cpsr().c == 0; //CC (carry clear)
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case 4: return cpsr().n == 1; //MI (negative)
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case 5: return cpsr().n == 0; //PL (positive)
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case 6: return cpsr().v == 1; //VS (overflow)
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case 7: return cpsr().v == 0; //VC (no overflow)
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case 8: return cpsr().c == 1 && cpsr().z == 0; //HI (unsigned higher)
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case 9: return cpsr().c == 0 || cpsr().z == 1; //LS (unsigned lower or same)
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case 10: return cpsr().n == cpsr().v; //GE (signed greater than or equal)
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case 11: return cpsr().n != cpsr().v; //LT (signed less than)
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case 12: return cpsr().z == 0 && cpsr().n == cpsr().v; //GT (signed greater than)
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case 13: return cpsr().z == 1 || cpsr().n != cpsr().v; //LE (signed less than or equal)
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case 14: return true; //AL (always)
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case 15: return false; //NV (never)
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}
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}
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auto ARM::bit(uint32 result) -> uint32 {
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if(cpsr().t || instruction() & (1 << 20)) {
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cpsr().n = result >> 31;
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cpsr().z = result == 0;
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cpsr().c = carryout();
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}
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return result;
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}
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auto ARM::add(uint32 source, uint32 modify, bool carry) -> uint32 {
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uint32 result = source + modify + carry;
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if(cpsr().t || instruction() & (1 << 20)) {
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uint32 overflow = ~(source ^ modify) & (source ^ result);
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cpsr().n = result >> 31;
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cpsr().z = result == 0;
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cpsr().c = (1u << 31) & (overflow ^ source ^ modify ^ result);
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cpsr().v = (1u << 31) & (overflow);
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}
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return result;
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}
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auto ARM::sub(uint32 source, uint32 modify, bool carry) -> uint32 {
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return add(source, ~modify, carry);
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}
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auto ARM::mul(uint32 product, uint32 multiplicand, uint32 multiplier) -> uint32 {
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idle();
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if((multiplier & 0xffffff00) != 0x00000000 && (multiplier & 0xffffff00) != 0xffffff00) idle();
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if((multiplier & 0xffff0000) != 0x00000000 && (multiplier & 0xffff0000) != 0xffff0000) idle();
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if((multiplier & 0xff000000) != 0x00000000 && (multiplier & 0xff000000) != 0xff000000) idle();
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product += multiplicand * multiplier;
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if(cpsr().t || instruction() & (1 << 20)) {
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cpsr().n = product >> 31;
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cpsr().z = product == 0;
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}
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return product;
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}
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auto ARM::lsl(uint32 source, uint8 shift) -> uint32 {
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carryout() = cpsr().c;
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if(shift == 0) return source;
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carryout() = shift > 32 ? 0 : source & (1 << 32 - shift);
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source = shift > 31 ? 0 : source << shift;
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return source;
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}
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auto ARM::lsr(uint32 source, uint8 shift) -> uint32 {
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carryout() = cpsr().c;
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if(shift == 0) return source;
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carryout() = shift > 32 ? 0 : source & (1 << shift - 1);
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source = shift > 31 ? 0 : source >> shift;
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return source;
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}
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auto ARM::asr(uint32 source, uint8 shift) -> uint32 {
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carryout() = cpsr().c;
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if(shift == 0) return source;
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carryout() = shift > 32 ? source & (1 << 31) : source & (1 << shift - 1);
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source = shift > 31 ? (int32)source >> 31 : (int32)source >> shift;
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return source;
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}
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auto ARM::ror(uint32 source, uint8 shift) -> uint32 {
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carryout() = cpsr().c;
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if(shift == 0) return source;
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if(shift &= 31)
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source = source << 32 - shift | source >> shift;
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carryout() = source & (1 << 31);
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return source;
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}
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auto ARM::rrx(uint32 source) -> uint32 {
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carryout() = source & 1;
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return (cpsr().c << 31) | (source >> 1);
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}
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