Re: Using floating point instructions
Re: Using floating point instructions
- Subject: Re: Using floating point instructions
- From: Greg Parker <email@hidden>
- Date: Tue, 06 Dec 2016 13:41:53 -0800
> On Dec 6, 2016, at 7:27 AM, G 3 <email@hidden> wrote:
>
> I'm working on a program that calls PowerPC assembly floating point instructions from C. It would have calls like this:
>
> double inputA, inputB, answer;
> asm volatile("fadd %0, %1, %2" : "=f" (answer) : "f" (inputA), "f" (inputB)); // answer = inputA + inputB
>
> The odd thing is it only works in the debug configuration in XCode. In Release configuration, I see this error:
> error: output constraint 0 must specify a single register
> error: output operand 0 must use '&' constraint
>
> Is there a way to fix this problem?
You'll get better answers from a clang list such as email@hidden. Most of the audience here probably does not have a copy of clang that can compile PowerPC code.
Why are you using constraint "f" here? I would expect you to use "d" with variables of type double.
--
Greg Parker email@hidden <mailto:email@hidden> Runtime Wrangler
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