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| author | Kartik K. Agaram <vc@akkartik.com> | 2017-10-14 22:53:18 -0700 |
|---|---|---|
| committer | Kartik K. Agaram <vc@akkartik.com> | 2017-10-14 23:00:05 -0700 |
| commit | c67ca4b92674620f3cae3b9301471e0321a7936c (patch) | |
| tree | fb471c4ae56d38f6731d913b1450eec025ae7351 /subx/012indirect_addressing.cc | |
| parent | 0cb3c774b207c8a94bf9f9775e99e7d593d1e4fe (diff) | |
| download | mu-c67ca4b92674620f3cae3b9301471e0321a7936c.tar.gz | |
4065
subx: 'compare' Hopefully I've implemented the 'sense' of comparisons right..
Diffstat (limited to 'subx/012indirect_addressing.cc')
| -rw-r--r-- | subx/012indirect_addressing.cc | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/subx/012indirect_addressing.cc b/subx/012indirect_addressing.cc index e209d690..38c3d234 100644 --- a/subx/012indirect_addressing.cc +++ b/subx/012indirect_addressing.cc @@ -192,3 +192,83 @@ case 0x33: { // xor r/m32 with r32 +run: 'not' of effective address +run: effective address is mem at address 0x60 (reg 3) +run: storing 0xf0f0ff00 + +//:: compare + +:(scenario compare_mem_at_r32_with_r32_greater) +% Reg[0].i = 0x60; +% SET_WORD_IN_MEM(0x60, 0x0a0b0c0d); +% Reg[3].i = 0x0a0b0c07; +# op ModRM SIB displacement immediate + 39 18 # compare EBX (reg 3) with *EAX (reg 0) ++run: compare reg 3 with effective address ++run: effective address is mem at address 0x60 (reg 0) ++run: SF=0; ZF=0; OF=0 + +:(scenario compare_mem_at_r32_with_r32_lesser) +% Reg[0].i = 0x60; +% SET_WORD_IN_MEM(0x60, 0x0a0b0c07); +% Reg[3].i = 0x0a0b0c0d; +# op ModRM SIB displacement immediate + 39 18 # compare EBX (reg 3) with *EAX (reg 0) ++run: compare reg 3 with effective address ++run: effective address is mem at address 0x60 (reg 0) ++run: SF=1; ZF=0; OF=0 + +:(scenario compare_mem_at_r32_with_r32_equal) +% Reg[0].i = 0x60; +% SET_WORD_IN_MEM(0x60, 0x0a0b0c0d); +% Reg[3].i = 0x0a0b0c0d; +# op ModRM SIB displacement immediate + 39 18 # compare EBX (reg 3) with *EAX (reg 0) ++run: compare reg 3 with effective address ++run: effective address is mem at address 0x60 (reg 0) ++run: SF=0; ZF=1; OF=0 + +//: + +:(scenario compare_r32_with_mem_at_r32_greater) +% Reg[0].i = 0x60; +% SET_WORD_IN_MEM(0x60, 0x0a0b0c07); +% Reg[3].i = 0x0a0b0c0d; +# op ModRM SIB displacement immediate + 3b 18 # compare *EAX (reg 0) with EBX (reg 3) ++run: compare effective address with reg 3 ++run: effective address is mem at address 0x60 (reg 0) ++run: SF=0; ZF=0; OF=0 + +:(before "End Single-Byte Opcodes") +case 0x3b: { // compare r/m32 with r32 + uint8_t modrm = next(); + uint8_t reg1 = (modrm>>3)&0x7; + trace(2, "run") << "compare effective address with reg " << NUM(reg1) << end(); + int32_t arg1 = Reg[reg1].i; + int32_t* arg2 = effective_address(modrm); + int32_t tmp1 = arg1 - *arg2; + SF = (tmp1 < 0); + ZF = (tmp1 == 0); + int64_t tmp2 = arg1 - *arg2; + OF = (tmp1 != tmp2); + trace(2, "run") << "SF=" << SF << "; ZF=" << ZF << "; OF=" << OF << end(); + break; +} + +:(scenario compare_r32_with_mem_at_r32_lesser) +% Reg[0].i = 0x60; +% SET_WORD_IN_MEM(0x60, 0x0a0b0c0d); +% Reg[3].i = 0x0a0b0c07; +# op ModRM SIB displacement immediate + 3b 18 # compare *EAX (reg 0) with EBX (reg 3) ++run: compare effective address with reg 3 ++run: effective address is mem at address 0x60 (reg 0) ++run: SF=1; ZF=0; OF=0 + +:(scenario compare_r32_with_mem_at_r32_equal) +% Reg[0].i = 0x60; +% SET_WORD_IN_MEM(0x60, 0x0a0b0c0d); +% Reg[3].i = 0x0a0b0c0d; +# op ModRM SIB displacement immediate + 3b 18 # compare *EAX (reg 0) with EBX (reg 3) ++run: compare effective address with reg 3 ++run: effective address is mem at address 0x60 (reg 0) ++run: SF=0; ZF=1; OF=0 |