instructions_0FB0.c

#include <stdint.h>

#include "instruction_defs.h"
#include "emulator_functions.h"
#include "modrm.h"

/*
 * mov r32 rm8: 2 bytes
 * Copies value of zero-extended rm8 value to r32.
 * 2 byte: op (0FB6)
 * 1 byte: ModR/M
 */
void movzx_r32_rm8(Emulator *emu)
{
    emu->eip += 2;
    ModRM modrm = create_modrm();
    parse_modrm(emu, &modrm);
    uint32_t rm16 = 0 | get_rm8(emu, &modrm);
    set_r32(emu, &modrm, rm16);
}

/*
 * mov r32 rm16: 2 bytes
 * Copies value of zero-extended rm16 value to r32.
 * 2 byte: op (0FB7)
 * 1 byte: ModR/M
 */
void movzx_r32_rm16(Emulator *emu)
{
    emu->eip += 2;
    ModRM modrm = create_modrm();
    parse_modrm(emu, &modrm);
    uint32_t rm16 = 0 | get_rm16(emu, &modrm);
    set_r32(emu, &modrm, rm16);
}

/*
 * movsx r32 rm8: 3 bytes
 * Copies sign-extended rm8 value to r32.
 * 2 byte: op (0FBE)
 * 1 byte: ModR/M
 */
void movsx_r32_rm8(Emulator *emu)
{
    emu->eip += 2;
    ModRM modrm = create_modrm();
    parse_modrm(emu, &modrm);
    uint8_t rm8 = get_rm8(emu, &modrm);
    uint8_t sign = rm8 >> 7 & 1;
    if (sign == 1)
    {
        uint32_t sign_extended = 0xFFFFFF00 | rm8;
        set_r32(emu, &modrm, sign_extended);
    }
    else
    {
        set_r32(emu, &modrm, (uint32_t)rm8);
    }
}

/*
 * movsx r32 rm16: 3 bytes
 * Copies sign-extended rm16 value to r32.
 * 2 byte: op (0FBF)
 * 1 byte: ModR/M
 */
void movsx_r32_rm16(Emulator *emu)
{
    emu->eip += 2;
    ModRM modrm = create_modrm();
    parse_modrm(emu, &modrm);
    uint16_t rm16 = get_rm16(emu, &modrm);
    uint8_t sign = rm16 >> 15 & 1;
    if (sign == 1)
    {
        uint32_t sign_extended = 0xFFFF0000 | rm16;
        set_r32(emu, &modrm, sign_extended);
    }
    else
    {
        set_r32(emu, &modrm, (uint32_t)rm16);
    }
}