diff options
-rw-r--r-- | subx/015immediate_addressing.cc | 79 |
1 files changed, 68 insertions, 11 deletions
diff --git a/subx/015immediate_addressing.cc b/subx/015immediate_addressing.cc index 4210c024..4212b80f 100644 --- a/subx/015immediate_addressing.cc +++ b/subx/015immediate_addressing.cc @@ -1012,27 +1012,84 @@ case 7: { ZF = (tmp1 == 0); const int64_t tmp2 = static_cast<int64_t>(*signed_arg1) - signed_arg2; OF = (tmp1 != tmp2); + const uint32_t unsigned_arg1 = static_cast<uint32_t>(*signed_arg1); + const uint32_t unsigned_arg2 = static_cast<uint32_t>(signed_arg2); + const uint32_t tmp3 = unsigned_arg1 - unsigned_arg2; + const uint64_t tmp4 = static_cast<uint64_t>(unsigned_arg1) - unsigned_arg2; + CF = (tmp3 != tmp4); trace(Callstack_depth+1, "run") << "SF=" << SF << "; ZF=" << ZF << "; CF=" << CF << "; OF=" << OF << end(); break; } :(code) -void test_compare_imm32_with_r32_lesser() { - Reg[EBX].i = 0x0d0c0b07; +void test_compare_rm32_with_imm32_lesser_unsigned_and_signed() { + Reg[EAX].i = 0x0a0b0c07; run( "== 0x1\n" // code segment // op ModR/M SIB displacement immediate - " 81 fb 0a 0b 0c 0d \n" // compare 0x0d0c0b0a with EBX - // ModR/M in binary: 11 (direct mode) 111 (subop compare) 011 (dest EBX) + " 81 f8 0d 0c 0b 0a \n" // compare EAX with imm32 + // ModR/M in binary: 11 (direct mode) 111 (subop compare) 000 (dest EAX) ); CHECK_TRACE_CONTENTS( "run: combine imm32 with r/m32\n" - "run: r/m32 is EBX\n" - "run: imm32 is 0x0d0c0b0a\n" + "run: r/m32 is EAX\n" + "run: imm32 is 0x0a0b0c0d\n" + "run: subop compare\n" + "run: SF=1; ZF=0; CF=1; OF=0\n" + ); +} + +void test_compare_rm32_with_imm32_lesser_unsigned_and_signed_due_to_overflow() { + Reg[EAX].i = 0x7fffffff; // largest positive signed integer + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 81 f8 00 00 00 80\n" // compare EAX with smallest negative signed integer + // ModR/M in binary: 11 (direct mode) 111 (subop compare) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: combine imm32 with r/m32\n" + "run: r/m32 is EAX\n" + "run: imm32 is 0x80000000\n" + "run: subop compare\n" + "run: SF=1; ZF=0; CF=1; OF=1\n" + ); +} + +void test_compare_rm32_with_imm32_lesser_signed() { + Reg[EAX].i = 0xffffffff; // -1 + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 81 f8 01 00 00 00\n" // compare EAX with 1 + // ModR/M in binary: 11 (direct mode) 111 (subop compare) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: combine imm32 with r/m32\n" + "run: r/m32 is EAX\n" + "run: imm32 is 0x00000001\n" + "run: subop compare\n" "run: SF=1; ZF=0; CF=0; OF=0\n" ); } +void test_compare_rm32_with_imm32_lesser_unsigned() { + Reg[EAX].i = 0x00000001; // 1 + run( + "== 0x1\n" // code segment + // op ModR/M SIB displacement immediate + " 81 f8 ff ff ff ff\n" // compare EAX with -1 + // ModR/M in binary: 11 (direct mode) 111 (subop compare) 000 (dest EAX) + ); + CHECK_TRACE_CONTENTS( + "run: combine imm32 with r/m32\n" + "run: r/m32 is EAX\n" + "run: imm32 is 0xffffffff\n" + "run: subop compare\n" + "run: SF=0; ZF=0; CF=1; OF=0\n" + ); +} + :(code) void test_compare_imm32_with_r32_equal() { Reg[EBX].i = 0x0d0c0b0a; @@ -1071,20 +1128,20 @@ void test_compare_imm32_with_mem_at_r32_greater() { :(code) void test_compare_imm32_with_mem_at_r32_lesser() { - Reg[EBX].i = 0x2000; + Reg[EAX].i = 0x2000; run( "== 0x1\n" // code segment // op ModR/M SIB displacement immediate - " 81 3b 0a 0b 0c 0d \n" // compare 0x0d0c0b0a with *EBX - // ModR/M in binary: 00 (indirect mode) 111 (subop compare) 011 (dest EBX) + " 81 38 0a 0b 0c 0d \n" // compare 0x0d0c0b0a with *EAX + // ModR/M in binary: 00 (indirect mode) 111 (subop compare) 000 (dest EAX) "== 0x2000\n" // data segment "07 0b 0c 0d\n" // 0x0d0c0b07 ); CHECK_TRACE_CONTENTS( "run: combine imm32 with r/m32\n" - "run: effective address is 0x00002000 (EBX)\n" + "run: effective address is 0x00002000 (EAX)\n" "run: imm32 is 0x0d0c0b0a\n" - "run: SF=1; ZF=0; CF=0; OF=0\n" + "run: SF=1; ZF=0; CF=1; OF=0\n" ); } |