1/*	$OpenBSD: e_sqrt.c,v 1.7 2016/09/12 19:47:02 guenther Exp $	*/
2
3/*
4 * Written by Martynas Venckus.  Public domain
5 */
6
7#include <sys/types.h>
8#include <math.h>
9
10#define	FPSCR_PR	(1 << 19)
11#define	FPSCR_SZ	(1 << 20)
12
13double
14sqrt(double d)
15{
16	register_t fpscr, nfpscr;
17
18	__asm__ volatile ("sts fpscr, %0" : "=r" (fpscr));
19
20	/* Set floating-point mode to double-precision. */
21	nfpscr = fpscr | FPSCR_PR;
22
23	/* Do not set SZ and PR to 1 simultaneously. */
24	nfpscr &= ~FPSCR_SZ;
25
26	__asm__ volatile ("lds %0, fpscr" : : "r" (nfpscr));
27	__asm__ volatile ("fsqrt %0" : "+f" (d));
28
29	/* Restore fp status/control register. */
30	__asm__ volatile ("lds %0, fpscr" : : "r" (fpscr));
31
32	return (d);
33}
34DEF_STD(sqrt);
35LDBL_CLONE(sqrt);
36