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_scalbnl.c b/libm/upstream-freebsd/lib/msun/src/s_scalbnl.c
index 28b0cf9..6044c1b 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_scalbnl.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_scalbnl.c
@@ -1,71 +1,49 @@
-/* @(#)s_scalbn.c 5.1 93/09/24 */
/*
- * ====================================================
- * 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 <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
+#include <math.h>
+#include <float.h>
+#include "math_private.h"
+#include "fpmath.h"
/*
* scalbnl (long double x, int n)
* scalbnl(x,n) returns x* 2**n computed by exponent
* manipulation rather than by actually performing an
* exponentiation or a multiplication.
*/
-
-/*
- * We assume that a long double has a 15-bit exponent. On systems
- * where long double is the same as double, scalbnl() is an alias
- * for scalbn(), so we don't use this routine.
- */
-
-#include <float.h>
-#include <math.h>
-
-#include "fpmath.h"
-
-#if LDBL_MAX_EXP != 0x4000
-#error "Unsupported long double format"
-#endif
-
-static const long double
-huge = 0x1p16000L,
-tiny = 0x1p-16000L;
-
-long double
-scalbnl (long double x, int n)
+#if (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+long double scalbnl(long double x, int n)
{
union IEEEl2bits u;
- int k;
- u.e = x;
- k = u.bits.exp; /* extract exponent */
- if (k==0) { /* 0 or subnormal x */
- if ((u.bits.manh|u.bits.manl)==0) return x; /* +-0 */
- u.e *= 0x1p+128;
- k = u.bits.exp - 128;
- if (n< -50000) return tiny*x; /*underflow*/
- }
- if (k==0x7fff) return x+x; /* NaN or Inf */
- k = k+n;
- if (k >= 0x7fff) return huge*copysignl(huge,x); /* overflow */
- if (k > 0) /* normal result */
- {u.bits.exp = k; return u.e;}
- if (k <= -128) {
- if (n > 50000) /* in case integer overflow in n+k */
- return huge*copysign(huge,x); /*overflow*/
- else
- return tiny*copysign(tiny,x); /*underflow*/
- }
- k += 128; /* subnormal result */
- u.bits.exp = k;
- return u.e*0x1p-128;
-}
+ if (n > 16383) {
+ x *= 0x1p16383L;
+ n -= 16383;
+ if (n > 16383) {
+ x *= 0x1p16383L;
+ n -= 16383;
+ if (n > 16383)
+ n = 16383;
+ }
+ } else if (n < -16382) {
+ x *= 0x1p-16382L * 0x1p113L;
+ n += 16382 - 113;
+ if (n < -16382) {
+ x *= 0x1p-16382L * 0x1p113L;
+ n += 16382 - 113;
+ if (n < -16382)
+ n = -16382;
+ }
+ }
+ u.e = 1.0;
+ u.xbits.expsign = 0x3fff + n;
+ return x * u.e;
+}
__strong_reference(scalbnl, ldexpl);
+#endif
+