libm: sync with upstream.
There's potential here to maybe lose some/all of builtins.cpp, but I'll
look at that separately later.
Test: treehugger
Change-Id: I2c2bc1d0753affdd214daeb09fa1ac7cd73db347
diff --git a/libm/upstream-freebsd/lib/msun/src/s_scalbnf.c b/libm/upstream-freebsd/lib/msun/src/s_scalbnf.c
index 21d001c..8cf1e01 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_scalbnf.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_scalbnf.c
@@ -1,57 +1,41 @@
-/* s_scalbnf.c -- float version of s_scalbn.c.
- * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
- */
-
/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ * Copyright (c) 2005-2020 Rich Felker, et al.
*
- * Developed at SunPro, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice
- * is preserved.
- * ====================================================
+ * SPDX-License-Identifier: MIT
+ *
+ * Please see https://git.musl-libc.org/cgit/musl/tree/COPYRIGHT
+ * for all contributors to musl.
*/
+#include <math.h>
+#include <stdint.h>
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-#include "math.h"
-#include "math_private.h"
-
-static const float
-two25 = 3.355443200e+07, /* 0x4c000000 */
-twom25 = 2.9802322388e-08, /* 0x33000000 */
-huge = 1.0e+30,
-tiny = 1.0e-30;
-
-float
-scalbnf (float x, int n)
+float scalbnf(float x, int n)
{
- int32_t k,ix;
- GET_FLOAT_WORD(ix,x);
- k = (ix&0x7f800000)>>23; /* extract exponent */
- if (k==0) { /* 0 or subnormal x */
- if ((ix&0x7fffffff)==0) return x; /* +-0 */
- x *= two25;
- GET_FLOAT_WORD(ix,x);
- k = ((ix&0x7f800000)>>23) - 25;
- if (n< -50000) return tiny*x; /*underflow*/
- }
- if (k==0xff) return x+x; /* NaN or Inf */
- k = k+n;
- if (k > 0xfe) return huge*copysignf(huge,x); /* overflow */
- if (k > 0) /* normal result */
- {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
- if (k <= -25) {
- if (n > 50000) /* in case integer overflow in n+k */
- return huge*copysignf(huge,x); /*overflow*/
- else
- return tiny*copysignf(tiny,x); /*underflow*/
+ union {float f; uint32_t i;} u;
+ float_t y = x;
+
+ if (n > 127) {
+ y *= 0x1p127f;
+ n -= 127;
+ if (n > 127) {
+ y *= 0x1p127f;
+ n -= 127;
+ if (n > 127)
+ n = 127;
+ }
+ } else if (n < -126) {
+ y *= 0x1p-126f * 0x1p24f;
+ n += 126 - 24;
+ if (n < -126) {
+ y *= 0x1p-126f * 0x1p24f;
+ n += 126 - 24;
+ if (n < -126)
+ n = -126;
+ }
}
- k += 25; /* subnormal result */
- SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
- return x*twom25;
+ u.i = (uint32_t)(0x7f+n)<<23;
+ x = y * u.f;
+ return x;
}
__strong_reference(scalbnf, ldexpf);