Practical C Programming

How to do it…

To multiply two numbers using the inline assembly language in C, perform the following steps:

1. Load the two values to be multiplied into eax and ebx registers
2. Multiply the contents of the eax and ebx registers and store the result in the eax register
3. Display the content of the eax register on the screen

The program for multiplying two digits using inline assembly code is as follows:

#include <stdio.h>#include <stdint.h>int main(int argc, char **argv){    int32_t var1=10, var2=20, multi = 0;    asm volatile ("imull %%ebx,%%eax;"        : "=a" (multi)                  : "a" (var1), "b" (var2)     );    printf("Multiplication = %d\n", multi);    return 0;}

Now, let's go behind the scenes.