My question is about the assembly result of a long long variable divided by a
long variable.
Assume two global variable declarations:
long long a1 = 3;
long a2 = 4;
I guess a1/a2 could be assembled to something like (on ia32/linux) :
movl a1, %eax
movl a1+4, %edx
idivl a2
Is this correct ?
However the result compiled by GCC 4.1.1 is much more complicated. As a
matter of fact,
the following C program:
long long a1 = 15;
long a2 = 5;
int f() { return a1/a2; }
is compiled to a long assembly program below (gcc -O1 -S tmp1.c) . Why ?
.file "tmp1.c"
.globl __divdi3
.text
.globl f
.type f, @function
f:
pushl %ebp
movl %esp, %ebp
subl $24, %esp
movl a2, %eax
movl %eax, 8(%esp)
cltd
movl %edx, 12(%esp)
movl a1, %eax
movl a1+4, %edx
movl %eax, (%esp)
movl %edx, 4(%esp)
call __divdi3
leave
ret
.size f, .-f
.globl a1
.data
.align 8
.type a1, @object
.size a1, 8
a1:
.long 15
.long 0
.globl a2
.align 4
.type a2, @object
.size a2, 4
a2:
.long 5
.ident "GCC: (GNU) 4.1.1"
.section .note.GNU-stack,"",@progbits
--
View this message in context: http://www.nabble.com/Question%3A-assembly-result-of-a-long-long-variable-divided-by-a-long-variable-tf2677244.html#a7466698
Sent from the gcc - Help mailing list archive at Nabble.com.
