diff options
Diffstat (limited to 'subx/013direct_addressing.cc')
| -rw-r--r-- | subx/013direct_addressing.cc | 86 |
1 files changed, 70 insertions, 16 deletions
diff --git a/subx/013direct_addressing.cc b/subx/013direct_addressing.cc index c94a152d..87983e3d 100644 --- a/subx/013direct_addressing.cc +++ b/subx/013direct_addressing.cc @@ -25,8 +25,19 @@ case 0x01: { // add r32 to r/m32 uint8_t modrm = next(); uint8_t arg2 = (modrm>>3)&0x7; trace(Callstack_depth+1, "run") << "add " << rname(arg2) << " to r/m32" << end(); - int32_t* arg1 = effective_address(modrm); - BINARY_ARITHMETIC_OP(+, *arg1, Reg[arg2].i); + int32_t* signed_arg1 = effective_address(modrm); + int64_t signed_full_result = *signed_arg1 + Reg[arg2].i; + *signed_arg1 += Reg[arg2].i; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << *signed_arg1 << end(); + SF = (*signed_arg1 < 0); + ZF = (*signed_arg1 == 0); + OF = (*signed_arg1 != signed_full_result); + // set CF + uint32_t unsigned_arg1 = static_cast<uint32_t>(*signed_arg1); + uint32_t unsigned_result = unsigned_arg1 + Reg[arg2].u; + uint64_t unsigned_full_result = unsigned_arg1 + Reg[arg2].u; + CF = (unsigned_result != unsigned_full_result); + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } @@ -129,8 +140,19 @@ case 0x29: { // subtract r32 from r/m32 const uint8_t modrm = next(); const uint8_t arg2 = (modrm>>3)&0x7; trace(Callstack_depth+1, "run") << "subtract " << rname(arg2) << " from r/m32" << end(); - int32_t* arg1 = effective_address(modrm); - BINARY_ARITHMETIC_OP(-, *arg1, Reg[arg2].i); + int32_t* signed_arg1 = effective_address(modrm); + int64_t signed_full_result = *signed_arg1 - Reg[arg2].i; + *signed_arg1 -= Reg[arg2].i; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << *signed_arg1 << end(); + SF = (*signed_arg1 < 0); + ZF = (*signed_arg1 == 0); + OF = (*signed_arg1 != signed_full_result); + // set CF + uint32_t unsigned_arg1 = static_cast<uint32_t>(*signed_arg1); + uint32_t unsigned_result = unsigned_arg1 - Reg[arg2].u; + uint64_t unsigned_full_result = unsigned_arg1 - Reg[arg2].u; + CF = (unsigned_result != unsigned_full_result); + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } @@ -215,19 +237,26 @@ void test_multiply_r32_into_r32() { // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) ); CHECK_TRACE_CONTENTS( - "run: multiply r/m32 into EBX\n" + "run: multiply EBX by r/m32\n" "run: r/m32 is EAX\n" "run: storing 0x00000008\n" ); } :(before "End Two-Byte Opcodes Starting With 0f") -case 0xaf: { // multiply r32 into r/m32 +case 0xaf: { // multiply r32 by r/m32 const uint8_t modrm = next(); - const uint8_t arg2 = (modrm>>3)&0x7; - trace(Callstack_depth+1, "run") << "multiply r/m32 into " << rname(arg2) << end(); - const int32_t* arg1 = effective_address(modrm); - BINARY_ARITHMETIC_OP(*, Reg[arg2].i, *arg1); + const uint8_t arg1 = (modrm>>3)&0x7; + trace(Callstack_depth+1, "run") << "multiply " << rname(arg1) << " by r/m32" << end(); + const int32_t* arg2 = effective_address(modrm); + int64_t full_result = Reg[arg1].i * (*arg2); + Reg[arg1].i *= (*arg2); + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << Reg[arg1].i << end(); + SF = (Reg[arg1].i < 0); + ZF = (Reg[arg1].i == 0); + OF = (Reg[arg1].i != full_result); + CF = OF; + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } @@ -316,6 +345,7 @@ case 7: { // divide EDX:EAX by r/m32, storing quotient in EAX and remainder in assert(divisor != 0); Reg[EAX].i = dividend/divisor; // quotient Reg[EDX].i = dividend%divisor; // remainder + // flag state undefined trace(Callstack_depth+1, "run") << "quotient: 0x" << HEXWORD << Reg[EAX].i << end(); trace(Callstack_depth+1, "run") << "remainder: 0x" << HEXWORD << Reg[EDX].i << end(); break; @@ -605,8 +635,16 @@ case 0x21: { // and r32 with r/m32 const uint8_t modrm = next(); const uint8_t arg2 = (modrm>>3)&0x7; trace(Callstack_depth+1, "run") << "and " << rname(arg2) << " with r/m32" << end(); - int32_t* arg1 = effective_address(modrm); - BINARY_BITWISE_OP(&, *arg1, Reg[arg2].u); + // bitwise ops technically operate on unsigned numbers, but it makes no + // difference + int32_t* signed_arg1 = effective_address(modrm); + *signed_arg1 &= Reg[arg2].i; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << *signed_arg1 << end(); + SF = (*signed_arg1 >> 31); + ZF = (*signed_arg1 == 0); + CF = false; + OF = false; + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } @@ -637,8 +675,16 @@ case 0x09: { // or r32 with r/m32 const uint8_t modrm = next(); const uint8_t arg2 = (modrm>>3)&0x7; trace(Callstack_depth+1, "run") << "or " << rname(arg2) << " with r/m32" << end(); - int32_t* arg1 = effective_address(modrm); - BINARY_BITWISE_OP(|, *arg1, Reg[arg2].u); + // bitwise ops technically operate on unsigned numbers, but it makes no + // difference + int32_t* signed_arg1 = effective_address(modrm); + *signed_arg1 |= Reg[arg2].i; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << *signed_arg1 << end(); + SF = (*signed_arg1 >> 31); + ZF = (*signed_arg1 == 0); + CF = false; + OF = false; + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } @@ -669,8 +715,16 @@ case 0x31: { // xor r32 with r/m32 const uint8_t modrm = next(); const uint8_t arg2 = (modrm>>3)&0x7; trace(Callstack_depth+1, "run") << "xor " << rname(arg2) << " with r/m32" << end(); - int32_t* arg1 = effective_address(modrm); - BINARY_BITWISE_OP(^, *arg1, Reg[arg2].u); + // bitwise ops technically operate on unsigned numbers, but it makes no + // difference + int32_t* signed_arg1 = effective_address(modrm); + *signed_arg1 ^= Reg[arg2].i; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << *signed_arg1 << end(); + SF = (*signed_arg1 >> 31); + ZF = (*signed_arg1 == 0); + CF = false; + OF = false; + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } |