> /usr/local/linare-gcc-5.2/bin/gcc -S -O3 -march=armv8-a+lse test.c
>
> add_int:
> ldaddal w0, w0, [x1]
> add w2, w0, w0
> mov w0, w2
> ret
Am I going mad, or does this just return the contents of the memory
location * 2.
ldaddal w0, w0, [x1]
Returns the original contents of [x1] in w0.
add w2, w0, w0
doubles it.
mov w0, w2
returns it.
I think __sync_add_and_fetch should return the updated contents.
Here is the test C code again.
int add_int(int add_value, int *dest)
{
return __sync_add_and_fetch(dest, add_value);
}
Regards,
Ed.
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