On Mon, 2010-01-04 at 01:19 +0530, prashant rawat wrote:
> Thanks a lot :)
> However, what if I make variable a global?
> Now it will be there in the assembly code.
> #include<stdio.h>
> int b, a=0;
> int main ()
> {
> while (a < 100)
> {
> b = 10;
> a = a + 1;
> printf ("%d\n", a);
> }
> printf ("%d, %d\n", b, a);
> return 0;
> }
>
Yes, it will be in the assembly language, but its value is ignored if it
is => 100. Otherwise, it's just set to 100:
.file "loop_invar_2.c"
.section .rodata.str1.1,"aMS",@progbits,1
.LC0:
.string "%d\n"
.text
.p2align 4,,15
.globl main
.type main, @function
main:
.LFB22:
.cfi_startproc
subq $24, %rsp
.cfi_def_cfa_offset 32
cmpl $99, a(%rip) # compare a to 99
jg .L6 # greater, ignore loop stuff
movl $10, 12(%rsp) # b = 10;
movl $100, a(%rip) # a = 100;
movl $10, %edx
.L3:
leaq 12(%rsp), %rax
movl $.LC0, %esi
movl $1, %edi
movq %rax, c(%rip)
xorl %eax, %eax
call __printf_chk
xorl %eax, %eax
addq $24, %rsp
ret
.p2align 4,,10
.p2align 3
.L6:
movl 12(%rsp), %edx # use current b (garbage)
jmp .L3
.cfi_endproc
.LFE22:
.size main, .-main
.globl a
.bss
.align 4
.type a, @object
.size a, 4
a:
.zero 4
.comm c,8,8
.ident "GCC: (Ubuntu 4.4.1-4ubuntu8) 4.4.1"
.section .note.GNU-stack,"",@progbits
