Stuart Cracraft wrote:
>
> Hi - someone supplied the following code
> in a C++ program to me that g++ compiled.
>
> However, I want to convert it to use it in
> a regular C program that gcc can compile.
>
> Needless to say, the construct does not work
> for GNU C.
>
> I've tried placing each line of the assembly
> in asm("...."); and that also fails to get
> gcc to compile it.
>
> What would the equivalent GNU C function for the
> below be?
>
> static unsigned int bitScanAndReset(unsigned long long & bb) {
>
> __asm
> {
> xor edx, edx
> mov ebx, [bb]
> xor eax, eax
> inc edx
> bsf ecx, [ebx]
> jnz found
> bsf ecx, [ebx+4]
> lea ebx, [ebx+4]
> xor eax, 32
> found:
> shl edx, cl
> xor eax, ecx
> xor [ebx], edx
> }
> }
>
> Thanks,
>
> Stuart
>
>
Notice that the assembler used by gcc (as) uses by default the at&t assembly
syntax, and you have intel code.
You can either, translate the code to at&t syntax or use the -masm=intel
flag to compile (mount) this code.
read more on at&t syntax at:
http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html
Regards,
Marcelo Slomp
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