整数乘法

参考博客：https://blog.csdn.net/weixin_43216249/article/details/109315686

imul

imul具有三种格式：

imul 源操作数

这部分和mul大致相同，源操作数不能是立即数，同时注意符号位

imul 寄存器，源操作数

操作数必须是字或者双字，而不能是字节。

imul 寄存器，源操作数，立即数

其中，寄存器用来存放乘积，

实际测试代码：

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int a;
    a=2;
    for(int i=0;i!=10;i++)   
    {
        a=a*30;
        printf("%d\n",a);
        system("pause");
    }
    system("pause");
    return 0;
}

汇编对应代码：

test_mul.exe+1540 - 55                    - push rbp
test_mul.exe+1541 - 48 89 E5              - mov rbp,rsp
test_mul.exe+1544 - 48 83 EC 30           - sub rsp,30
test_mul.exe+1548 - E8 13010000           - call test_mul.exe+1660
test_mul.exe+154D - C7 45 FC 02000000     - mov [rbp-04],00000002
test_mul.exe+1554 - C7 45 F8 00000000     - mov [rbp-08],00000000
test_mul.exe+155B - 83 7D F8 0A           - cmp dword ptr [rbp-08],0A
test_mul.exe+155F - 74 2C                 - je test_mul.exe+158D
test_mul.exe+1561 - 8B 45 FC              - mov eax,[rbp-04]
test_mul.exe+1564 - 6B C0 1E              - imul eax,eax,1E
test_mul.exe+1567 - 89 45 FC              - mov [rbp-04],eax
test_mul.exe+156A - 8B 45 FC              - mov eax,[rbp-04]
test_mul.exe+156D - 89 C2                 - mov edx,eax
test_mul.exe+156F - 48 8D 0D 8A7A0000     - lea rcx,[test_mul.exe+9000]
test_mul.exe+1576 - E8 65660000           - call test_mul.exe+7BE0
test_mul.exe+157B - 48 8D 0D 827A0000     - lea rcx,[test_mul.exe+9004]
test_mul.exe+1582 - E8 695E0000           - call test_mul.exe+73F0
test_mul.exe+1587 - 83 45 F8 01           - add dword ptr [rbp-08],01
test_mul.exe+158B - EB CE                 - jmp test_mul.exe+155B
test_mul.exe+158D - 48 8D 0D 707A0000     - lea rcx,[test_mul.exe+9004]
test_mul.exe+1594 - E8 575E0000           - call test_mul.exe+73F0
test_mul.exe+1599 - B8 00000000           - mov eax,00000000
test_mul.exe+159E - 48 83 C4 30           - add rsp,30
test_mul.exe+15A2 - 5D                    - pop rbp
test_mul.exe+15A3 - C3                    - ret