diff options
Diffstat (limited to 'subx/011direct_addressing.cc')
| -rw-r--r-- | subx/011direct_addressing.cc | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/subx/011direct_addressing.cc b/subx/011direct_addressing.cc index 46c24828..2a948626 100644 --- a/subx/011direct_addressing.cc +++ b/subx/011direct_addressing.cc @@ -50,6 +50,7 @@ int32_t* effective_address(uint8_t modrm) { % Reg[3].i = 1; # op ModR/M SIB displacement immediate 29 d8 # subtract EBX from EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: subtract EBX from effective address +run: effective address is EAX +run: storing 0x00000009 @@ -71,6 +72,7 @@ case 0x29: { // subtract r32 from r/m32 % Reg[3].i = 0x000000ff; # op ModR/M SIB displacement immediate 21 d8 # and EBX with destination EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: and EBX with effective address +run: effective address is EAX +run: storing 0x0000000d @@ -92,6 +94,7 @@ case 0x21: { // and r32 with r/m32 % Reg[3].i = 0xa0b0c0d0; # op ModR/M SIB displacement immediate 09 d8 # or EBX with destination EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: or EBX with effective address +run: effective address is EAX +run: storing 0xaabbccdd @@ -113,6 +116,7 @@ case 0x09: { // or r32 with r/m32 % Reg[3].i = 0xaabbc0d0; # op ModR/M SIB displacement immediate 31 d8 # xor EBX with destination EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: xor EBX with effective address +run: effective address is EAX +run: storing 0xa0b0ccdd @@ -133,6 +137,7 @@ case 0x31: { // xor r32 with r/m32 % Reg[3].i = 0x0f0f00ff; # op ModR/M SIB displacement immediate f7 c3 # not EBX +# ModR/M in binary: 11 (direct mode) 000 (unused) 011 (dest EBX) +run: 'not' of effective address +run: effective address is EBX +run: storing 0xf0f0ff00 @@ -155,8 +160,9 @@ case 0xf7: { // xor r32 with r/m32 :(scenario compare_r32_with_r32_greater) % Reg[0].i = 0x0a0b0c0d; % Reg[3].i = 0x0a0b0c07; -# op ModRM SIB displacement immediate +# op ModR/M SIB displacement immediate 39 d8 # compare EBX with EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: compare EBX with effective address +run: effective address is EAX +run: SF=0; ZF=0; OF=0 @@ -180,8 +186,9 @@ case 0x39: { // set SF if r/m32 < r32 :(scenario compare_r32_with_r32_lesser) % Reg[0].i = 0x0a0b0c07; % Reg[3].i = 0x0a0b0c0d; -# op ModRM SIB displacement immediate +# op ModR/M SIB displacement immediate 39 d8 # compare EBX with EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: compare EBX with effective address +run: effective address is EAX +run: SF=1; ZF=0; OF=0 @@ -189,8 +196,9 @@ case 0x39: { // set SF if r/m32 < r32 :(scenario compare_r32_with_r32_equal) % Reg[0].i = 0x0a0b0c0d; % Reg[3].i = 0x0a0b0c0d; -# op ModRM SIB displacement immediate +# op ModR/M SIB displacement immediate 39 d8 # compare EBX with EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: compare EBX with effective address +run: effective address is EAX +run: SF=0; ZF=1; OF=0 @@ -199,8 +207,9 @@ case 0x39: { // set SF if r/m32 < r32 :(scenario copy_r32_to_r32) % Reg[3].i = 0xaf; -# op ModRM SIB displacement immediate +# op ModR/M SIB displacement immediate 89 d8 # copy EBX to EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: copy EBX to effective address +run: effective address is EAX +run: storing 0x000000af @@ -221,8 +230,9 @@ case 0x89: { // copy r32 to r/m32 :(scenario xchg_r32_with_r32) % Reg[3].i = 0xaf; % Reg[0].i = 0x2e; -# op ModRM SIB displacement immediate +# op ModR/M SIB displacement immediate 87 d8 # exchange EBX with EAX +# ModR/M in binary: 11 (direct mode) 011 (src EBX) 000 (dest EAX) +run: exchange EBX with effective address +run: effective address is EAX +run: storing 0x000000af in effective address @@ -247,7 +257,7 @@ case 0x87: { // exchange r32 with r/m32 :(scenario push_r32) % Reg[ESP].u = 0x64; % Reg[EBX].i = 0x0000000a; -# op ModRM SIB displacement immediate +# op ModR/M SIB displacement immediate 53 # push EBX to stack +run: push EBX +run: decrementing ESP to 0x00000060 @@ -280,7 +290,7 @@ void push(uint32_t val) { :(scenario pop_r32) % Reg[ESP].u = 0x60; % SET_WORD_IN_MEM(0x60, 0x0000000a); -# op ModRM SIB displacement immediate +# op ModR/M SIB displacement immediate 5b # pop stack to EBX +run: pop into EBX +run: popping value 0x0000000a |