libmwemu 0.24.1

x86 32/64bits and system internals emulator, for securely emulating malware and other stuff.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

//! Tests for the FCOMPP instruction.
//!
//! FCOMPP - Compare floating-point and pop twice
//!
//! Reference: /Users/int/dev/rax/docs/fcom:fcomp:fcompp.txt
//!
//! Opcode: DE D9 - FCOMPP ; Compare ST(0) with ST(1) and pop twice

use crate::*;

const DATA_ADDR: u64 = 0x2000;

fn write_f64(mem: u64, addr: u64, value: f64) {
    let mut emu = emu64();
    emu.maps.write_bytes_slice(addr, &value.to_le_bytes());
}

fn read_u16(mem: u64, addr: u64) -> u16 {
    let emu = emu64();
    let mut buf = [0u8; 2];
    emu.maps.read_bytes_buff(&mut buf, addr);
    u16::from_le_bytes(buf)
}

#[test]
fn test_fcompp_equal() {
    let mut emu = emu64();
    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, // FLD qword [0x2000]
        0xDD, 0x04, 0x25, 0x08, 0x20, 0x00, 0x00, // FLD qword [0x2008]
        0xDE, 0xD9, // FCOMPP
        0xDF, 0xE0, // FSTSW AX
        0x66, 0x89, 0x04, 0x25, 0x00, 0x30, 0x00, 0x00, // MOV [0x3000], AX
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 10.0);
    emu.maps.write_f64(DATA_ADDR + 8, 10.0);

    emu.run(None).unwrap();
    let status = emu.maps.read_word(0x3000).unwrap();
    // C3=1, C2=0, C0=0 for equal (bits 14, 10, 8)
    assert_eq!(status & 0x4500, 0x4000);
}

#[test]
fn test_fcompp_greater() {
    let mut emu = emu64();
    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, 0xDD, 0x04, 0x25, 0x08, 0x20, 0x00, 0x00, 0xDE,
        0xD9, // FCOMPP
        0xDF, 0xE0, // FSTSW AX
        0x66, 0x89, 0x04, 0x25, 0x00, 0x30, 0x00, 0x00, 0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 5.0);
    emu.maps.write_f64(DATA_ADDR + 8, 15.0);

    emu.run(None).unwrap();
    let status = emu.maps.read_word(0x3000).unwrap();
    // ST(0) > ST(1): 15 > 5, C3=0, C2=0, C0=0
    assert_eq!(status & 0x4500, 0x0000);
}

#[test]
fn test_fcompp_less() {
    let mut emu = emu64();
    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, 0xDD, 0x04, 0x25, 0x08, 0x20, 0x00, 0x00, 0xDE,
        0xD9, // FCOMPP
        0xDF, 0xE0, // FSTSW AX
        0x66, 0x89, 0x04, 0x25, 0x00, 0x30, 0x00, 0x00, 0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 15.0);
    emu.maps.write_f64(DATA_ADDR + 8, 5.0);

    emu.run(None).unwrap();
    let status = emu.maps.read_word(0x3000).unwrap();
    // ST(0) < ST(1): 5 < 15, C3=0, C2=0, C0=1
    assert_eq!(status & 0x4500, 0x0100);
}

#[test]
fn test_fcompp_negative_numbers() {
    let mut emu = emu64();
    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, 0xDD, 0x04, 0x25, 0x08, 0x20, 0x00, 0x00, 0xDE,
        0xD9, 0xDF, 0xE0, 0x66, 0x89, 0x04, 0x25, 0x00, 0x30, 0x00, 0x00, 0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, -10.0);
    emu.maps.write_f64(DATA_ADDR + 8, -5.0);

    emu.run(None).unwrap();
    let status = emu.maps.read_word(0x3000).unwrap();
    // -5 > -10, so ST(0) > ST(1)
    assert_eq!(status & 0x4500, 0x0000);
}

#[test]
fn test_fcompp_zero_comparison() {
    let mut emu = emu64();
    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, 0xDD, 0x04, 0x25, 0x08, 0x20, 0x00, 0x00, 0xDE,
        0xD9, 0xDF, 0xE0, 0x66, 0x89, 0x04, 0x25, 0x00, 0x30, 0x00, 0x00, 0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 0.0);
    emu.maps.write_f64(DATA_ADDR + 8, 0.0);

    emu.run(None).unwrap();
    let status = emu.maps.read_word(0x3000).unwrap();
    assert_eq!(status & 0x4500, 0x4000);
}

#[test]
fn test_fcompp_infinity() {
    let mut emu = emu64();
    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, 0xDD, 0x04, 0x25, 0x08, 0x20, 0x00, 0x00, 0xDE,
        0xD9, 0xDF, 0xE0, 0x66, 0x89, 0x04, 0x25, 0x00, 0x30, 0x00, 0x00, 0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 100.0);
    emu.maps.write_f64(DATA_ADDR + 8, f64::INFINITY);

    emu.run(None).unwrap();
    let status = emu.maps.read_word(0x3000).unwrap();
    // ST(0) > ST(1): infinity > 100
    assert_eq!(status & 0x4500, 0x0000);
}