github.com/afumu/libc@v0.0.6/musl/src/math/aarch64/fabs.c (about)

     1  #include <math.h>
     2  
     3  double fabs(double x)
     4  {
     5  	__asm__ ("fabs %d0, %d1" : "=w"(x) : "w"(x));
     6  	return x;
     7  }