I am back with a new post.
Today's topic is .. "how to check assembly of a C code ? "
There is a inbuilt option for this in gcc compiler
for example let say i have a file called "hello.c"
#include
void print(char *name)
{
printf("%s",name);
}
int main()
{
print("pankaj");
}
and when you compile the code with
$ gcc -S hello.c
A new file will be generated by the compiler called "hello.s", which will have the content like
.file "test.c"
.section .rodata
.LC0:
.string "%s"
.text
.globl print
.type print, @function
print:
pushl %ebp
movl %esp, %ebp
subl $8, %esp
movl 8(%ebp), %eax
movl %eax, 4(%esp)
movl $.LC0, (%esp)
call printf
leave
ret
.size print, .-print
.section .rodata
.LC1:
.string "pankaj"
.text
.globl main
.type main, @function
main:
leal 4(%esp), %ecx
andl $-16, %esp
pushl -4(%ecx)
pushl %ebp
movl %esp, %ebp
pushl %ecx
subl $20, %esp
movl $.LC1, (%esp)
call print
addl $20, %esp
popl %ecx
popl %ebp
leal -4(%ecx), %esp
ret
.size main, .-main
.ident "GCC: (Ubuntu 4.3.2-1ubuntu12) 4.3.2"
.section .note.GNU-stack,"",@progbits
so this is all for today ..
have fun..
with regards
Pankaj anand.
