diff options
Diffstat (limited to 'subx/013direct_addressing.cc')
| -rw-r--r-- | subx/013direct_addressing.cc | 308 |
1 files changed, 261 insertions, 47 deletions
diff --git a/subx/013direct_addressing.cc b/subx/013direct_addressing.cc index c2dfa911..2914e0dd 100644 --- a/subx/013direct_addressing.cc +++ b/subx/013direct_addressing.cc @@ -25,12 +25,75 @@ 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); + int32_t signed_result = *signed_arg1 + Reg[arg2].i; + SF = (signed_result < 0); + ZF = (signed_result == 0); + int64_t signed_full_result = static_cast<int64_t>(*signed_arg1) + Reg[arg2].i; + OF = (signed_result != 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 = static_cast<uint64_t>(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(); + *signed_arg1 = signed_result; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << *signed_arg1 << end(); break; } :(code) +void test_add_r32_to_r32_signed_overflow() { + Reg[EAX].i = 0x7fffffff; // largest positive signed integer + Reg[EBX].i = 1; + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 01 d8 \n" // add EBX to EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: add EBX to r/m32\n" + "run: r/m32 is EAX\n" + "run: SF=1; ZF=0; CF=0; OF=1\n" + "run: storing 0x80000000\n" + ); +} + +void test_add_r32_to_r32_unsigned_overflow() { + Reg[EAX].u = 0xffffffff; // largest unsigned number + Reg[EBX].u = 1; + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 01 d8 \n" // add EBX to EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: add EBX to r/m32\n" + "run: r/m32 is EAX\n" + "run: SF=0; ZF=1; CF=1; OF=0\n" + "run: storing 0x00000000\n" + ); +} + +void test_add_r32_to_r32_unsigned_and_signed_overflow() { + Reg[EAX].u = Reg[EBX].u = 0x80000000; // smallest negative signed integer + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 01 d8 \n" // add EBX to EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: add EBX to r/m32\n" + "run: r/m32 is EAX\n" + "run: SF=0; ZF=1; CF=1; OF=1\n" + "run: storing 0x00000000\n" + ); +} + +:(code) // Implement tables 2-2 and 2-3 in the Intel manual, Volume 2. // We return a pointer so that instructions can write to multiple bytes in // 'Mem' at once. @@ -111,18 +174,82 @@ 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); + int32_t signed_result = *signed_arg1 - Reg[arg2].i; + SF = (signed_result < 0); + ZF = (signed_result == 0); + int64_t signed_full_result = static_cast<int64_t>(*signed_arg1) - Reg[arg2].i; + OF = (signed_result != 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 = static_cast<uint64_t>(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(); + *signed_arg1 = signed_result; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << *signed_arg1 << end(); break; } +:(code) +void test_subtract_r32_from_r32_signed_overflow() { + Reg[EAX].i = 0x80000000; // smallest negative signed integer + Reg[EBX].i = 0x7fffffff; // largest positive signed integer + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 29 d8 \n" // subtract EBX from EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: subtract EBX from r/m32\n" + "run: r/m32 is EAX\n" + "run: SF=0; ZF=0; CF=0; OF=1\n" + "run: storing 0x00000001\n" + ); +} + +void test_subtract_r32_from_r32_unsigned_overflow() { + Reg[EAX].i = 0; + Reg[EBX].i = 1; + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 29 d8 \n" // subtract EBX from EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: subtract EBX from r/m32\n" + "run: r/m32 is EAX\n" + "run: SF=1; ZF=0; CF=1; OF=0\n" + "run: storing 0xffffffff\n" + ); +} + +void test_subtract_r32_from_r32_signed_and_unsigned_overflow() { + Reg[EAX].i = 0; + Reg[EBX].i = 0x80000000; // smallest negative signed integer + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 29 d8 \n" // subtract EBX from EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: subtract EBX from r/m32\n" + "run: r/m32 is EAX\n" + "run: SF=1; ZF=0; CF=1; OF=1\n" + "run: storing 0x80000000\n" + ); +} + //:: multiply :(before "End Initialize Op Names") put_new(Name, "f7", "negate/multiply/divide rm32 (with EAX and EDX if necessary) depending on subop (neg/mul/idiv)"); :(code) -void test_multiply_eax_by_r32() { +void test_multiply_EAX_by_r32() { Reg[EAX].i = 4; Reg[ECX].i = 3; run( @@ -148,7 +275,7 @@ case 0xf7: { switch (subop) { case 4: { // mul unsigned EAX by r/m32 trace(Callstack_depth+1, "run") << "subop: multiply EAX by r/m32" << end(); - const uint64_t result = Reg[EAX].u * static_cast<uint32_t>(*arg1); + const uint64_t result = static_cast<uint64_t>(Reg[EAX].u) * static_cast<uint32_t>(*arg1); Reg[EAX].u = result & 0xffffffff; Reg[EDX].u = result >> 32; OF = (Reg[EDX].u != 0); @@ -179,19 +306,27 @@ 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); + int32_t result = Reg[arg1].i * (*arg2); + SF = (Reg[arg1].i < 0); + ZF = (Reg[arg1].i == 0); + int64_t full_result = static_cast<int64_t>(Reg[arg1].i) * (*arg2); + OF = (Reg[arg1].i != full_result); + CF = OF; + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); + Reg[arg1].i = result; + trace(Callstack_depth+1, "run") << "storing 0x" << HEXWORD << Reg[arg1].i << end(); break; } @@ -253,7 +388,7 @@ void test_negate_can_overflow() { //:: divide with remainder -void test_divide_eax_by_rm32() { +void test_divide_EAX_by_rm32() { Reg[EAX].u = 7; Reg[EDX].u = 0; Reg[ECX].i = 3; @@ -280,13 +415,14 @@ 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; } :(code) -void test_divide_eax_by_negative_rm32() { +void test_divide_EAX_by_negative_rm32() { Reg[EAX].u = 7; Reg[EDX].u = 0; Reg[ECX].i = -3; @@ -305,7 +441,7 @@ void test_divide_eax_by_negative_rm32() { ); } -void test_divide_negative_eax_by_rm32() { +void test_divide_negative_EAX_by_rm32() { Reg[EAX].i = -7; Reg[EDX].i = -1; // sign extend Reg[ECX].i = 3; @@ -324,7 +460,7 @@ void test_divide_negative_eax_by_rm32() { ); } -void test_divide_negative_edx_eax_by_rm32() { +void test_divide_negative_EDX_EAX_by_rm32() { Reg[EAX].i = 0; // lower 32 bits are clear Reg[EDX].i = -7; Reg[ECX].i = 0x40000000; // 2^30 (largest positive power of 2) @@ -569,8 +705,16 @@ 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; } @@ -601,8 +745,16 @@ 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; } @@ -633,8 +785,16 @@ 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; } @@ -680,13 +840,13 @@ void test_compare_r32_with_r32_greater() { run( "== 0x1\n" // code segment // op ModR/M SIB displacement immediate - " 39 d8 \n" // compare EBX with EAX + " 39 d8 \n" // compare EAX with EBX // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) ); CHECK_TRACE_CONTENTS( - "run: compare EBX with r/m32\n" + "run: compare r/m32 with EBX\n" "run: r/m32 is EAX\n" - "run: SF=0; ZF=0; OF=0\n" + "run: SF=0; ZF=0; CF=0; OF=0\n" ); } @@ -694,32 +854,84 @@ void test_compare_r32_with_r32_greater() { case 0x39: { // set SF if r/m32 < r32 const uint8_t modrm = next(); const uint8_t reg2 = (modrm>>3)&0x7; - trace(Callstack_depth+1, "run") << "compare " << rname(reg2) << " with r/m32" << end(); - const int32_t* arg1 = effective_address(modrm); - const int32_t arg2 = Reg[reg2].i; - const int32_t tmp1 = *arg1 - arg2; - SF = (tmp1 < 0); - ZF = (tmp1 == 0); - const int64_t tmp2 = *arg1 - arg2; - OF = (tmp1 != tmp2); - trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; OF=" << OF << end(); + trace(Callstack_depth+1, "run") << "compare r/m32 with " << rname(reg2) << end(); + const int32_t* signed_arg1 = effective_address(modrm); + const int32_t signed_difference = *signed_arg1 - Reg[reg2].i; + SF = (signed_difference < 0); + ZF = (signed_difference == 0); + const int64_t signed_full_difference = static_cast<int64_t>(*signed_arg1) - Reg[reg2].i; + OF = (signed_difference != signed_full_difference); + // set CF + const uint32_t unsigned_arg1 = static_cast<uint32_t>(*signed_arg1); + const uint32_t unsigned_difference = unsigned_arg1 - Reg[reg2].u; + const uint64_t unsigned_full_difference = static_cast<uint64_t>(unsigned_arg1) - Reg[reg2].u; + CF = (unsigned_difference != unsigned_full_difference); + trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } :(code) -void test_compare_r32_with_r32_lesser() { +void test_compare_r32_with_r32_lesser_unsigned_and_signed() { Reg[EAX].i = 0x0a0b0c07; Reg[EBX].i = 0x0a0b0c0d; run( "== 0x1\n" // code segment // op ModR/M SIB displacement immediate - " 39 d8 \n" // compare EBX with EAX + " 39 d8 \n" // compare EAX with EBX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: compare r/m32 with EBX\n" + "run: r/m32 is EAX\n" + "run: SF=1; ZF=0; CF=1; OF=0\n" + ); +} + +void test_compare_r32_with_r32_lesser_unsigned_and_signed_due_to_overflow() { + Reg[EAX].i = 0x7fffffff; // largest positive signed integer + Reg[EBX].i = 0x80000000; // smallest negative signed integer + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 39 d8 \n" // compare EAX with EBX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: compare r/m32 with EBX\n" + "run: r/m32 is EAX\n" + "run: SF=1; ZF=0; CF=1; OF=1\n" + ); +} + +void test_compare_r32_with_r32_lesser_signed() { + Reg[EAX].i = 0xffffffff; // -1 + Reg[EBX].i = 0x00000001; // 1 + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 39 d8 \n" // compare EAX with EBX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: compare r/m32 with EBX\n" + "run: r/m32 is EAX\n" + "run: SF=1; ZF=0; CF=0; OF=0\n" + ); +} + +void test_compare_r32_with_r32_lesser_unsigned() { + Reg[EAX].i = 0x00000001; // 1 + Reg[EBX].i = 0xffffffff; // -1 + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 39 d8 \n" // compare EAX with EBX // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) ); CHECK_TRACE_CONTENTS( - "run: compare EBX with r/m32\n" + "run: compare r/m32 with EBX\n" "run: r/m32 is EAX\n" - "run: SF=1; ZF=0; OF=0\n" + "run: SF=0; ZF=0; CF=1; OF=0\n" ); } @@ -729,13 +941,13 @@ void test_compare_r32_with_r32_equal() { run( "== 0x1\n" // code segment // op ModR/M SIB displacement immediate - " 39 d8 \n" // compare EBX with EAX + " 39 d8 \n" // compare EAX and EBX // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) ); CHECK_TRACE_CONTENTS( - "run: compare EBX with r/m32\n" + "run: compare r/m32 with EBX\n" "run: r/m32 is EAX\n" - "run: SF=0; ZF=1; OF=0\n" + "run: SF=0; ZF=1; CF=0; OF=0\n" ); } @@ -971,7 +1183,8 @@ put_new(Name, "57", "push EDI to stack (push)"); :(code) void test_push_r32() { - Reg[ESP].u = 0x64; + Mem.push_back(vma(0xbd000000)); // manually allocate memory + Reg[ESP].u = 0xbd000008; Reg[EBX].i = 0x0000000a; run( "== 0x1\n" // code segment @@ -980,7 +1193,7 @@ void test_push_r32() { ); CHECK_TRACE_CONTENTS( "run: push EBX\n" - "run: decrementing ESP to 0x00000060\n" + "run: decrementing ESP to 0xbd000004\n" "run: pushing value 0x0000000a\n" ); } @@ -1015,9 +1228,9 @@ put_new(Name, "5f", "pop top of stack to EDI (pop)"); :(code) void test_pop_r32() { - Reg[ESP].u = 0x02000000; - Mem.push_back(vma(0x02000000)); // manually allocate memory - write_mem_i32(0x02000000, 0x0000000a); // ..before this write + Mem.push_back(vma(0xbd000000)); // manually allocate memory + Reg[ESP].u = 0xbd000008; + write_mem_i32(0xbd000008, 0x0000000a); // ..before this write run( "== 0x1\n" // code segment // op ModR/M SIB displacement immediate @@ -1028,7 +1241,7 @@ void test_pop_r32() { CHECK_TRACE_CONTENTS( "run: pop into EBX\n" "run: popping value 0x0000000a\n" - "run: incrementing ESP to 0x02000004\n" + "run: incrementing ESP to 0xbd00000c\n" ); } @@ -1054,5 +1267,6 @@ uint32_t pop() { trace(Callstack_depth+1, "run") << "popping value 0x" << HEXWORD << result << end(); Reg[ESP].u += 4; trace(Callstack_depth+1, "run") << "incrementing ESP to 0x" << HEXWORD << Reg[ESP].u << end(); + assert(Reg[ESP].u < AFTER_STACK); return result; } |