Lecture No. 01

Dated: 13-03-2025

Typical Compilation

Source Code

int expr(int n) {
    int d;
    d = 4 * n * n * (n + 1) * (n + 1)l
    return d;
}

Intel X86 Assembly Code

The source code above is converted into corresponding assembly code which is machine dependent. Meaning that the gcc compiler translates the source code according to the platform (machine) it is compiling on.

.globl _expr
_expr:
    pushl %ebp
    movl %esp, %ebp
    subl $24, %esp
    movl 8(%ebp), %eax
    movl %eax, %edx
    leal 0(,%edx,4), %eax
    movl %eax, %edx
    imull 8(%ebp), %edx
    movl 8(%ebp), %eax
    incl %eax
    imull %eax, %edx
    movl 8(%ebp), %eax
    incl %eax
    imull %eax, %edx
    movl %edx, -4(%ebp)
    movl -4(%ebp), %edx
    movl %edx, %eax
    jmp L2
    .align 4

L2:
    leave
    ret

Issues in Compilation

The translation process is complex and is done in multiple passes.
There is no unique translation from source language to destination language.