auto ARM7TDMI::ADD(uint32 source, uint32 modify, bool carry) -> uint32 { uint32 result = source + modify + carry; if(cpsr().t || opcode.bit(20)) { uint32 overflow = ~(source ^ modify) & (source ^ result); cpsr().v = 1 << 31 & (overflow); cpsr().c = 1 << 31 & (overflow ^ source ^ modify ^ result); cpsr().z = result == 0; cpsr().n = result.bit(31); } return result; } auto ARM7TDMI::ASR(uint32 source, uint8 shift) -> uint32 { carry = cpsr().c; if(shift == 0) return source; carry = shift > 32 ? source & 1 << 31 : source & 1 << shift - 1; source = shift > 31 ? (int32)source >> 31 : (int32)source >> shift; return source; } auto ARM7TDMI::BIT(uint32 result) -> uint32 { if(cpsr().t || opcode.bit(20)) { cpsr().c = carry; cpsr().z = result == 0; cpsr().n = result.bit(31); } return result; } auto ARM7TDMI::LSL(uint32 source, uint8 shift) -> uint32 { carry = cpsr().c; if(shift == 0) return source; carry = shift > 32 ? 0 : source & 1 << 32 - shift; source = shift > 31 ? 0 : source << shift; return source; } auto ARM7TDMI::LSR(uint32 source, uint8 shift) -> uint32 { carry = cpsr().c; if(shift == 0) return source; carry = shift > 32 ? 0 : source & 1 << shift - 1; source = shift > 31 ? 0 : source >> shift; return source; } auto ARM7TDMI::MUL(uint32 product, uint32 multiplicand, uint32 multiplier) -> uint32 { idle(); if(multiplier >> 8 && multiplier >> 8 != 0xffffff) idle(); if(multiplier >> 16 && multiplier >> 16 != 0xffff) idle(); if(multiplier >> 24 && multiplier >> 24 != 0xff) idle(); product += multiplicand * multiplier; if(cpsr().t || opcode.bit(20)) { cpsr().z = product == 0; cpsr().n = product.bit(31); } return product; } auto ARM7TDMI::ROR(uint32 source, uint8 shift) -> uint32 { carry = cpsr().c; if(shift == 0) return source; if(shift &= 31) source = source << 32 - shift | source >> shift; carry = source & 1 << 31; return source; } auto ARM7TDMI::RRX(uint32 source) -> uint32 { carry = source.bit(0); return cpsr().c << 31 | source >> 1; } auto ARM7TDMI::SUB(uint32 source, uint32 modify, bool carry) -> uint32 { return ADD(source, ~modify, carry); } auto ARM7TDMI::TST(uint4 mode) -> bool { switch(mode) { case 0: return cpsr().z == 1; //EQ (equal) case 1: return cpsr().z == 0; //NE (not equal) case 2: return cpsr().c == 1; //CS (carry set) case 3: return cpsr().c == 0; //CC (carry clear) case 4: return cpsr().n == 1; //MI (negative) case 5: return cpsr().n == 0; //PL (positive) case 6: return cpsr().v == 1; //VS (overflow) case 7: return cpsr().v == 0; //VC (no overflow) case 8: return cpsr().c == 1 && cpsr().z == 0; //HI (unsigned higher) case 9: return cpsr().c == 0 || cpsr().z == 1; //LS (unsigned lower or same) case 10: return cpsr().n == cpsr().v; //GE (signed greater than or equal) case 11: return cpsr().n != cpsr().v; //LT (signed less than) case 12: return cpsr().z == 0 && cpsr().n == cpsr().v; //GT (signed greater than) case 13: return cpsr().z == 1 || cpsr().n != cpsr().v; //LE (signed less than or equal) case 14: return true; //AL (always) case 15: return false; //NV (never) } unreachable; }