libmwemu 0.24.0

x86 32/64bits and system internals emulator, for securely emulating malware and other stuff.
Documentation 
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//! Tests for the FIDIV instruction.
//!
//! FIDIV - Divide floating-point by integer (m16int and m32int)
//!
//! Reference: /Users/int/dev/rax/docs/fdiv:fdivp:fidiv.txt
//!
//! Opcode: DE /6 - FIDIV m16int  ; ST(0) = ST(0) / m16int
//! Opcode: DA /6 - FIDIV m32int  ; ST(0) = ST(0) / m32int

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 write_i16(mem: u64, addr: u64, value: i16) {
    let mut emu = emu64();    emu.maps.write_bytes_slice(addr, &value.to_le_bytes());
}

fn write_i32(mem: u64, addr: u64, value: i32) {
    let mut emu = emu64();    emu.maps.write_bytes_slice(addr, &value.to_le_bytes());
}

fn read_f64(mem: u64, addr: u64) -> f64 {
    let emu = emu64();    let mut buf = [0u8; 8];
    emu.maps.read_bytes_buff(&mut buf, addr);
    f64::from_le_bytes(buf)
}

// FIDIV m16int tests
#[test]
fn test_fidiv_m16int_basic() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, // FLD qword [0x2000]
        0xDE, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00, // FIDIV word [0x2008]
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00, // FSTP qword [0x3000]
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 10.0);
    emu.maps.write_word(DATA_ADDR + 8, (2) as i16 as u16);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), 5.0);
}

#[test]
fn test_fidiv_m16int_negative_divisor() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDE, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 15.0);
    emu.maps.write_word(DATA_ADDR + 8, (-3) as i16 as u16);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), -5.0);
}

#[test]
fn test_fidiv_m16int_one() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDE, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 123.456);
    emu.maps.write_word(DATA_ADDR + 8, (1) as i16 as u16);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), 123.456);
}

#[test]
fn test_fidiv_m16int_fractional_result() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDE, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 1.0);
    emu.maps.write_word(DATA_ADDR + 8, (3) as i16 as u16);

    emu.run(None).unwrap();
    let result = emu.maps.read_f64(0x3000).unwrap();
    assert!((result - (1.0 / 3.0)).abs() < 1e-15);
}

#[test]
fn test_fidiv_m16int_max() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDE, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 100000.0);
    emu.maps.write_word(DATA_ADDR + 8, (i16::MAX) as i16 as u16);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), 100000.0 / i16::MAX as f64);
}

// FIDIV m32int tests
#[test]
fn test_fidiv_m32int_basic() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDA, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00, // FIDIV dword [0x2008]
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 1000.0);
    emu.maps.write_dword(DATA_ADDR + 8, (10) as i32 as u32);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), 100.0);
}

#[test]
fn test_fidiv_m32int_negative() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDA, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, -250.0);
    emu.maps.write_dword(DATA_ADDR + 8, (100) as i32 as u32);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), -2.5);
}

#[test]
fn test_fidiv_m32int_large_divisor() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDA, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 2000000.0);
    emu.maps.write_dword(DATA_ADDR + 8, (1000000) as i32 as u32);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), 2.0);
}

#[test]
fn test_fidiv_m32int_fractional() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDA, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 1.0);
    emu.maps.write_dword(DATA_ADDR + 8, (7) as i32 as u32);

    emu.run(None).unwrap();
    let result = emu.maps.read_f64(0x3000).unwrap();
    assert!((result - (1.0 / 7.0)).abs() < 1e-15);
}

#[test]
fn test_fidiv_chain() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00, // FLD 1000.0
        0xDA, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00, // FIDIV 10
        0xDA, 0x34, 0x25, 0x0C, 0x20, 0x00, 0x00, // FIDIV 5
        0xDA, 0x34, 0x25, 0x10, 0x20, 0x00, 0x00, // FIDIV 2
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 1000.0);
    emu.maps.write_dword(DATA_ADDR + 8, (10) as i32 as u32);
    emu.maps.write_dword(DATA_ADDR + 12, (5) as i32 as u32);
    emu.maps.write_dword(DATA_ADDR + 16, (2) as i32 as u32);

    emu.run(None).unwrap();
    assert_eq!(emu.maps.read_f64(0x3000).unwrap(), 10.0); // 1000 / 10 / 5 / 2
}

#[test]
fn test_fidiv_infinity() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDA, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, f64::INFINITY);
    emu.maps.write_dword(DATA_ADDR + 8, (5) as i32 as u32);

    emu.run(None).unwrap();
    let result = emu.maps.read_f64(0x3000).unwrap();
    assert!(result.is_infinite() && result.is_sign_positive());
}

#[test]
fn test_fidiv_zero_dividend() {
    let mut emu = emu64();    let code = [
        0xDD, 0x04, 0x25, 0x00, 0x20, 0x00, 0x00,
        0xDA, 0x34, 0x25, 0x08, 0x20, 0x00, 0x00,
        0xDD, 0x1C, 0x25, 0x00, 0x30, 0x00, 0x00,
        0xf4,
    ];
    emu.load_code_bytes(&code);
    emu.maps.write_f64(DATA_ADDR, 0.0);
    emu.maps.write_dword(DATA_ADDR + 8, (5) as i32 as u32);

    emu.run(None).unwrap();
    let result = emu.maps.read_f64(0x3000).unwrap();
    assert_eq!(result, 0.0);
    assert!(!result.is_sign_negative());
}