github.com/afumu/libc@v0.0.6/musl/src/math/i386/sqrtf.c (about)

     1  #include <math.h>
     2  
     3  float sqrtf(float x)
     4  {
     5  	long double t;
     6  	/* The long double result has sufficient precision so that
     7  	 * second rounding to float still keeps the returned value
     8  	 * correctly rounded, see Pierre Roux, "Innocuous Double
     9  	 * Rounding of Basic Arithmetic Operations". */
    10  	__asm__ ("fsqrt" : "=t"(t) : "0"(x));
    11  	return (float)t;
    12  }