On 11 May 2007 19:27, Paul Brook wrote:
>>> > result = __macf(operand1, operand2, operand3); >
>>> > }
>>> >
>>> > Requirement : I need the value of operand3 and result to be same >
>>> after calling the builtin. > But this is not happening.
>>>
>>> What do you mean, exactly? C only has call by value, and gcc's
>>> builtins can only return one value. Builtins don't change their
>>> arguments. If you want to update one of the arguments you'll have to
>>> pass a pointer to the builtin.
>>
>> After the builtin i want to have the following operations also to carried
>> out operand3 = result ;
>
> Why do you want this to happen?
I think what he means is he wants operand 3 and operand zero to be placed in
the same register, hence the "0" constraint. As to quite why it's not
working, I don't know. A very similar pattern, only with "=&" modifiers on
operand zero, works fine for me under 3.4.4.
cheers,
DaveK
--
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