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authorDenis Vlasenko <vda.linux@googlemail.com>2009-01-03 13:51:12 +0000
committerDenis Vlasenko <vda.linux@googlemail.com>2009-01-03 13:51:12 +0000
commitb994ff9e32473ef3779cb23b4974295f3ba08aef (patch)
treeb25aec85165e003e4fc2a04480a2fba63d3e1c00 /libm/s_scalbn.c
parent15a971616c3e2f373264d0a2e4cd87aa11042737 (diff)
libm: remove scalbln implementation, it seems to be less correct than scalbn.
instead, either alias scalbln to scalbn if int == long on this arch, or just call scalbn form scalbln. text data bss dec hex filename - 45297 180 4 45481 b1a9 lib/libm.so + 44969 180 4 45153 b061 lib/libm.so
Diffstat (limited to 'libm/s_scalbn.c')
-rw-r--r--libm/s_scalbn.c72
1 files changed, 47 insertions, 25 deletions
diff --git a/libm/s_scalbn.c b/libm/s_scalbn.c
index c98ea9d1c..bb14802d8 100644
--- a/libm/s_scalbn.c
+++ b/libm/s_scalbn.c
@@ -11,7 +11,7 @@
/*
* scalbn (double x, int n)
- * scalbn(x,n) returns x* 2**n computed by exponent
+ * scalbn(x,n) returns x* 2**n computed by exponent
* manipulation rather than by actually performing an
* exponentiation or a multiplication.
*/
@@ -20,35 +20,57 @@
#include "math_private.h"
static const double
-two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
-twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
+two54 = 1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
+twom54 = 5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
huge = 1.0e+300,
tiny = 1.0e-300;
double scalbn(double x, int n)
{
- int32_t k,hx,lx;
- EXTRACT_WORDS(hx,lx,x);
- k = (hx&0x7ff00000)>>20; /* extract exponent */
- if (k==0) { /* 0 or subnormal x */
- if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
- x *= two54;
- GET_HIGH_WORD(hx,x);
- k = ((hx&0x7ff00000)>>20) - 54;
- if (n< -50000) return tiny*x; /*underflow*/
- }
- if (k==0x7ff) return x+x; /* NaN or Inf */
- k = k+n;
- if (k > 0x7fe) return huge*copysign(huge,x); /* overflow */
- if (k > 0) /* normal result */
- {SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;}
- if (k <= -54) {
- if (n > 50000) /* in case integer overflow in n+k */
- return huge*copysign(huge,x); /*overflow*/
- else return tiny*copysign(tiny,x); /*underflow*/
+ int32_t k, hx, lx;
+
+ EXTRACT_WORDS(hx, lx, x);
+ k = (hx & 0x7ff00000) >> 20; /* extract exponent */
+ if (k == 0) { /* 0 or subnormal x */
+ if ((lx | (hx & 0x7fffffff)) == 0)
+ return x; /* +-0 */
+ x *= two54;
+ GET_HIGH_WORD(hx, x);
+ k = ((hx & 0x7ff00000) >> 20) - 54;
+ }
+ if (k == 0x7ff)
+ return x + x; /* NaN or Inf */
+ k = k + n;
+ if (k > 0x7fe)
+ return huge * copysign(huge, x); /* overflow */
+ if (n < -50000)
+ return tiny * copysign(tiny, x); /* underflow */
+ if (k > 0) { /* normal result */
+ SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
+ return x;
}
- k += 54; /* subnormal result */
- SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20));
- return x*twom54;
+ if (k <= -54) {
+ if (n > 50000) /* in case integer overflow in n+k */
+ return huge * copysign(huge, x); /* overflow */
+ return tiny * copysign(tiny, x); /* underflow */
+ }
+ k += 54; /* subnormal result */
+ SET_HIGH_WORD(x, (hx & 0x800fffff) | (k << 20));
+ return x * twom54;
}
libm_hidden_def(scalbn)
+
+#if LONG_MAX == INT_MAX
+/* strong_alias(scalbn, scalbln) - "error: conflicting types for 'scalbln'"
+ * because it tries to declare "typeof(scalbn) scalbln;"
+ * which tries to give "int" parameter to scalbln.
+ * Doing it by hand:
+ */
+__typeof(scalbln) scalbln __attribute__((alias("scalbn")));
+#else
+double scalbln(double x, long n)
+{
+ return scalbn(x, n);
+}
+#endif
+libm_hidden_def(scalbln)