diff options
| -rw-r--r-- | subx/015immediate_addressing.cc | 51 | ||||
| -rw-r--r-- | subx/034compute_segment_address.cc | 2 |
2 files changed, 51 insertions, 2 deletions
diff --git a/subx/015immediate_addressing.cc b/subx/015immediate_addressing.cc index 30f96523..eedf81a3 100644 --- a/subx/015immediate_addressing.cc +++ b/subx/015immediate_addressing.cc @@ -6,7 +6,7 @@ put_new(Name, "05", "add imm32 to EAX (add)"); :(before "End Single-Byte Opcodes") case 0x05: { // add imm32 to EAX int32_t signed_arg2 = next32(); - trace(Callstack_depth+1, "run") << "add imm32 0x" << HEXWORD << signed_arg2 << " to reg EAX" << end(); + trace(Callstack_depth+1, "run") << "add imm32 0x" << HEXWORD << signed_arg2 << " to EAX" << end(); int32_t signed_result = Reg[EAX].i + signed_arg2; SF = (signed_result < 0); ZF = (signed_result == 0); @@ -23,6 +23,55 @@ case 0x05: { // add imm32 to EAX break; } +:(code) +void test_add_imm32_to_EAX_signed_overflow() { + Reg[EAX].i = 0x7fffffff; // largest positive signed integer + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 05 01 00 00 00 \n" // add 1 to EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: add imm32 0x00000001 to EAX\n" + "run: SF=1; ZF=0; CF=0; OF=1\n" + "run: storing 0x80000000\n" + ); +} + +void test_add_imm32_to_EAX_unsigned_overflow() { + Reg[EAX].u = 0xffffffff; // largest unsigned number + Reg[EBX].u = 1; + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 05 01 00 00 00 \n" // add 1 to EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: add imm32 0x00000001 to EAX\n" + "run: SF=0; ZF=1; CF=1; OF=0\n" + "run: storing 0x00000000\n" + ); +} + +void test_add_imm32_to_EAX_unsigned_and_signed_overflow() { + Reg[EAX].u = 0x80000000; // smallest negative signed integer + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 05 00 00 00 80 \n" // add 0x80000000 to EAX + // ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: add imm32 0x80000000 to EAX\n" + "run: SF=0; ZF=1; CF=1; OF=1\n" + "run: storing 0x00000000\n" + ); +} + +//: + :(before "End Initialize Op Names") put_new(Name, "81", "combine rm32 with imm32 based on subop (add/sub/and/or/xor/cmp)"); diff --git a/subx/034compute_segment_address.cc b/subx/034compute_segment_address.cc index a1b7482d..47311219 100644 --- a/subx/034compute_segment_address.cc +++ b/subx/034compute_segment_address.cc @@ -14,7 +14,7 @@ void test_segment_name() { "load: 0x09000056 -> 0b\n" "load: 0x09000057 -> 0c\n" "load: 0x09000058 -> 0d\n" - "run: add imm32 0x0d0c0b0a to reg EAX\n" + "run: add imm32 0x0d0c0b0a to EAX\n" "run: storing 0x0d0c0b0a\n" ); } |