1
2
3 :(scenario add_imm32_to_r32)
4 % Reg[3].i = 1;
5
6 81 c3 0a 0b 0c 0d
7 +run: combine imm32 0x0d0c0b0a with effective address
8 +run: effective address is reg 3
9 +run: subop add
10 +run: storing 0x0d0c0b0b
11
12 :(before "End Single-Byte Opcodes")
13 case 0x81: {
14 uint8_t modrm = next();
15 int32_t arg2 = imm32();
16 trace(2, "run") << "combine imm32 0x" << HEXWORD << arg2 << " with effective address" << end();
17 int32_t* arg1 = effective_address(modrm);
18 uint8_t subop = (modrm>>3)&0x7;
19 switch (subop) {
20 case 0:
21 ¦ trace(2, "run") << "subop add" << end();
22 ¦ BINARY_ARITHMETIC_OP(+, *arg1, arg2);
23 ¦ break;
24
25 default:
26 ¦ cerr << "unrecognized sub-opcode after 81: " << NUM(subop) << '\n';
27 ¦ exit(1);
28 }
29 break;
30 }
31
32
33
34 :(scenario add_imm32_to_mem_at_r32)
35 % Reg[3].i = 0x60;
36 % Mem.at(0x60) = 1;
37
38 81 03 0a 0b 0c 0d
39 +run: combine imm32 0x0d0c0b0a with effective address
40 +run: effective address is mem at address 0x60 (reg 3)
41 +run: subop add
42 +run: storing 0x0d0c0b0b
43
44
45
46 :(scenario subtract_imm32_from_eax)
47 % Reg[EAX].i = 0x0d0c0baa;
48
49 2d 0a 0b 0c 0d
50 +run: subtract imm32 0x0d0c0b0a from reg EAX
51 +run: storing 0x000000a0
52
53 :(before "End Single-Byte Opcodes")
54 case 0x2d: {
55 int32_t arg2 = imm32();
56 trace(2, "run") << "subtract imm32 0x" << HEXWORD << arg2 << " from reg EAX" << end();
57 BINARY_ARITHMETIC_OP(-, Reg[EAX].i, arg2);
58 break;
59 }
60
61
62
63 :(scenario subtract_imm32_from_mem_at_r32)
64 % Reg[3].i = 0x60;
65 % Mem.at(0x60) = 10;
66
67 81 2b 01 00 00 00
68 +run: combine imm32 0x00000001 with effective address
69 +run: effective address is mem at address 0x60 (reg 3)
70 +run: subop subtract
71 +run: storing 0x00000009
72
73
74
75 :(scenario subtract_imm32_from_r32)
76 % Reg[3].i = 10;
77
78 81 eb 01 00 00 00
79 +run: combine imm32 0x00000001 with effective address
80 +run: effective address is reg 3
81 +run: subop subtract
82 +run: storing 0x00000009
83
84 :(before "End Op 81 Subops")
85 case 5: {
86 trace(2, "run") << "subop subtract" << end();
87 BINARY_ARITHMETIC_OP(-, *arg1, arg2);
88 break;
89 }