Thanks Andrew,
Could you tell me which version works for you ?
Thanks
Preeti.
On Wed, Jul 7, 2010 at 9:10 AM, Andrew Haley <aph@xxxxxxxxxx> wrote:
> On 07/07/2010 05:00 PM, Preeti Sharma wrote:
>
>> Thanks for the response :
>> also wanted you to know that the problem is only for a 64 bit value ;
>> it compiles fine for a 32 bit int.
>
> Yes, I get the same problem with 4.1.2.
>
> Maybe you should upgrade.
>
> Andrew.
>
>
>> On Wed, Jul 7, 2010 at 8:43 AM, Andrew Haley <aph@xxxxxxxxxx> wrote:
>>> On 07/07/2010 04:26 PM, Preeti Sharma wrote:
>>>> I am trying to use __sync_fetch_and_add with type as "long long" .
>>>>
>>>> This gives me the link error :
>>>> undefined reference to `__sync_fetch_and_add_8'
>>>>
>>>> This compiles for a "int " type though. I am using the the gcc option
>>>> -march=i686
>>>>
>>>> Is it possible to do a 64 bit integer operation atomically with the
>>>> __sync .. builtin functions ?
>>>
>>> Works for me:
>>>
>>> long long a;
>>>
>>> t()
>>> {
>>> __sync_fetch_and_add(&a, 1);
>>> }
>>>
>>> $ gcc -S t.c -m32 -march=i686 -O2
>>>
>>> .file "t.c"
>>> .text
>>> .p2align 4,,15
>>> .globl t
>>> .type t, @function
>>> t:
>>> pushl %ebp
>>> movl %esp, %ebp
>>> subl $12, %esp
>>> movl %ebx, (%esp)
>>> movl %esi, 4(%esp)
>>> movl %edi, 8(%esp)
>>> movl a, %eax
>>> movl a+4, %edx
>>> .L2:
>>> movl %eax, %esi
>>> movl %edx, %edi
>>> addl $1, %esi
>>> adcl $0, %edi
>>> movl %esi, %ebx
>>> movl %edi, %ecx
>>> lock cmpxchg8b a
>>> jne .L2
>>> movl (%esp), %ebx
>>> movl 4(%esp), %esi
>>> movl 8(%esp), %edi
>>> movl %ebp, %esp
>>> popl %ebp
>>> ret
>>> .size t, .-t
>>> .comm a,8,8
>>> .ident "GCC: (GNU) 4.4.3 20100127 (Red Hat 4.4.3-4)"
>>> .section .note.GNU-stack,"",@progbits
>>>
>>>
>
>
