Optimize scalbln
authorUlrich Drepper <drepper@gmail.com>
Wed, 11 Jan 2012 17:49:16 +0000 (12:49 -0500)
committerUlrich Drepper <drepper@gmail.com>
Wed, 11 Jan 2012 17:49:16 +0000 (12:49 -0500)
ChangeLog
sysdeps/ieee754/dbl-64/s_scalbln.c
sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c [new file with mode: 0644]
sysdeps/ieee754/flt-32/s_scalblnf.c
sysdeps/ieee754/ldbl-96/s_scalblnl.c

index 9ebbdf9..7b87e2c 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2012-01-11  Ulrich Drepper  <drepper@gmail.com>
+
+       * sysdeps/ieee754/dbl-64/s_scalbln.c: Add branch prediction.
+       * sysdeps/ieee754/flt-32/s_scalblnf.c: Likewise.
+       * sysdeps/ieee754/ldbl-96/s_scalblnl.c: Likewise.
+       * sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c: New file.
+
 2012-01-10  Ulrich Drepper  <drepper@gmail.com>
 
        * sysdeps/ieee754/dbl-64/wordsize-64/s_modf.c: New file.
@@ -9,9 +16,9 @@
        * math/bits/mathcalls.h: Add const attribute to fmin and fmax.
 
        * sysdeps/ieee754/dbl-64/s_scalbn.c: Add branch prediction.
-       * sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c: Likewise.
        * sysdeps/ieee754/flt-32/s_scalbnf.c: Likewise.
        * sysdeps/ieee754/ldbl-96/s_scalbnl.c: Likewise.
+       * sysdeps/ieee754/dbl-64/wordsize-64/s_scalbn.c: New file.
 
        * math/bits/math-finite.h: Add ldexp support.
 
index aa6134f..89174b4 100644 (file)
@@ -1,4 +1,3 @@
-/* @(#)s_scalbn.c 5.1 93/09/24 */
 /*
  * ====================================================
  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
@@ -10,10 +9,6 @@
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: s_scalbn.c,v 1.8 1995/05/10 20:48:08 jtc Exp $";
-#endif
-
 /*
  * scalbn (double x, int n)
  * scalbn(x,n) returns x* 2**n  computed by  exponent
@@ -24,44 +19,37 @@ static char rcsid[] = "$NetBSD: s_scalbn.c,v 1.8 1995/05/10 20:48:08 jtc Exp $";
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const double
-#else
-static double
-#endif
 two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
 twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
 huge   = 1.0e+300,
 tiny   = 1.0e-300;
 
-#ifdef __STDC__
-       double __scalbln (double x, long int n)
-#else
-       double __scalbln (x,n)
-       double x; long int n;
-#endif
+double
+__scalbln (double x, long 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 */
+       k = (hx&0x7ff00000)>>20;                /* extract exponent */
+       if (__builtin_expect(k==0, 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 (n> 50000 || k >  0x7fe)
+       if (__builtin_expect(k==0x7ff, 0)) return x+x;  /* NaN or Inf */
+       k = k+n;
+       if (__builtin_expect(n> 50000 || k >  0x7fe, 0))
          return huge*__copysign(huge,x); /* overflow  */
-       if (n< -50000) return tiny*__copysign(tiny,x); /*underflow*/
-        if (k > 0)                             /* normal result */
+       if (__builtin_expect(n< -50000, 0))
+         return tiny*__copysign(tiny,x); /*underflow*/
+       if (__builtin_expect(k > 0, 1))         /* normal result */
            {SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20)); return x;}
-        if (k <= -54)
+       if (k <= -54)
          return tiny*__copysign(tiny,x);       /*underflow*/
-        k += 54;                               /* subnormal result */
+       k += 54;                                /* subnormal result */
        SET_HIGH_WORD(x,(hx&0x800fffff)|(k<<20));
-        return x*twom54;
+       return x*twom54;
 }
 weak_alias (__scalbln, scalbln)
 #ifdef NO_LONG_DOUBLE
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_scalbln.c
new file mode 100644 (file)
index 0000000..d6b97b5
--- /dev/null
@@ -0,0 +1,60 @@
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * 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.
+ * ====================================================
+ */
+
+/*
+ * scalbn (double x, int n)
+ * scalbn(x,n) returns x* 2**n  computed by  exponent
+ * manipulation rather than by actually performing an
+ * exponentiation or a multiplication.
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+static const double
+two54   =  1.80143985094819840000e+16, /* 0x43500000, 0x00000000 */
+twom54  =  5.55111512312578270212e-17, /* 0x3C900000, 0x00000000 */
+huge   = 1.0e+300,
+tiny   = 1.0e-300;
+
+double
+__scalbln (double x, long int n)
+{
+       int64_t ix;
+       int64_t k;
+       EXTRACT_WORDS64(ix,x);
+       k = (ix >> 52) & 0x7ff;                 /* extract exponent */
+       if (__builtin_expect(k==0, 0)) {        /* 0 or subnormal x */
+           if ((ix & UINT64_C(0xfffffffffffff))==0) return x; /* +-0 */
+           x *= two54;
+           EXTRACT_WORDS64(ix,x);
+           k = ((ix >> 52) & 0x7ff) - 54;
+           }
+       if (__builtin_expect(k==0x7ff, 0)) return x+x;  /* NaN or Inf */
+       k = k+n;
+       if (__builtin_expect(n> 50000 || k >  0x7fe, 0))
+         return huge*__copysign(huge,x); /* overflow  */
+       if (__builtin_expect(n< -50000, 0))
+         return tiny*__copysign(tiny,x); /*underflow*/
+       if (__builtin_expect(k > 0, 1))         /* normal result */
+           {INSERT_WORDS64(x,(ix&UINT64_C(0x800fffffffffffff))|(k<<52));
+             return x;}
+       if (k <= -54)
+         return tiny*__copysign(tiny,x);       /*underflow*/
+       k += 54;                                /* subnormal result */
+       INSERT_WORDS64(x,(ix&INT64_C(0x800fffffffffffff))|(k<<52));
+       return x*twom54;
+}
+weak_alias (__scalbln, scalbln)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__scalbln, __scalblnl)
+weak_alias (__scalbln, scalblnl)
+#endif
index 4ed4873..5256c32 100644 (file)
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: s_scalbnf.c,v 1.4 1995/05/10 20:48:10 jtc Exp $";
-#endif
-
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const float
-#else
-static float
-#endif
 two25   =  3.355443200e+07,    /* 0x4c000000 */
 twom25  =  2.9802322388e-08,   /* 0x33000000 */
 huge   = 1.0e+30,
 tiny   = 1.0e-30;
 
-#ifdef __STDC__
-       float __scalblnf (float x, long int n)
-#else
-       float __scalblnf (x,n)
-       float x; long int n;
-#endif
+float
+__scalblnf (float x, long 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 */
+       k = (ix&0x7f800000)>>23;                /* extract exponent */
+       if (__builtin_expect(k==0, 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 (k==0xff) return x+x;               /* NaN or Inf */
-        k = k+n;
-        if (n> 50000 || k >  0xfe)
+       if (__builtin_expect(k==0xff, 0)) return x+x;   /* NaN or Inf */
+       k = k+n;
+       if (__builtin_expect(n> 50000 || k >  0xfe, 0))
          return huge*copysignf(huge,x); /* overflow  */
-       if (n< -50000)
+       if (__builtin_expect(n< -50000, 0))
          return tiny*copysignf(tiny,x);        /*underflow*/
-        if (k > 0)                             /* normal result */
+       if (__builtin_expect(k > 0, 1))         /* normal result */
            {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;}
-        if (k <= -25)
+       if (k <= -25)
            return tiny*copysignf(tiny,x);      /*underflow*/
-        k += 25;                               /* subnormal result */
+       k += 25;                                /* subnormal result */
        SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23));
-        return x*twom25;
+       return x*twom25;
 }
 weak_alias (__scalblnf, scalblnf)
index 8e556fa..ada587b 100644 (file)
  * ====================================================
  */
 
-#if defined(LIBM_SCCS) && !defined(lint)
-static char rcsid[] = "$NetBSD: $";
-#endif
-
 /*
  * scalbnl (long double x, int n)
  * scalbnl(x,n) returns x* 2**n  computed by  exponent
@@ -28,44 +24,36 @@ static char rcsid[] = "$NetBSD: $";
 #include "math.h"
 #include "math_private.h"
 
-#ifdef __STDC__
 static const long double
-#else
-static long double
-#endif
 two63   =  4.50359962737049600000e+15,
 twom63  =  1.08420217248550443400e-19,
 huge   = 1.0e+4900L,
 tiny   = 1.0e-4900L;
 
-#ifdef __STDC__
-       long double __scalblnl (long double x, long int n)
-#else
-       long double __scalblnl (x,n)
-       long double x; long int n;
-#endif
+long double
+__scalblnl (long double x, long int n)
 {
        int32_t k,es,hx,lx;
        GET_LDOUBLE_WORDS(es,hx,lx,x);
-        k = es&0x7fff;                         /* extract exponent */
-        if (k==0) {                            /* 0 or subnormal x */
-            if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
+       k = es&0x7fff;                          /* extract exponent */
+       if (__builtin_expect(k==0, 0)) {        /* 0 or subnormal x */
+           if ((lx|(hx&0x7fffffff))==0) return x; /* +-0 */
            x *= two63;
            GET_LDOUBLE_EXP(es,x);
            k = (hx&0x7fff) - 63;
            }
-        if (k==0x7fff) return x+x;             /* NaN or Inf */
-        k = k+n;
-        if (n> 50000 || k > 0x7ffe)
+       if (__builtin_expect(k==0x7fff, 0)) return x+x; /* NaN or Inf */
+       k = k+n;
+       if (__builtin_expect(n> 50000 || k > 0x7ffe, 0))
          return huge*__copysignl(huge,x); /* overflow  */
-       if (n< -50000)
+       if (__builtin_expect(n< -50000, 0))
          return tiny*__copysignl(tiny,x);
-        if (k > 0)                             /* normal result */
+       if (__builtin_expect(k > 0, 1))         /* normal result */
            {SET_LDOUBLE_EXP(x,(es&0x8000)|k); return x;}
-        if (k <= -63)
+       if (k <= -63)
            return tiny*__copysignl(tiny,x);    /*underflow*/
-        k += 63;                               /* subnormal result */
+       k += 63;                                /* subnormal result */
        SET_LDOUBLE_EXP(x,(es&0x8000)|k);
-        return x*twom63;
+       return x*twom63;
 }
 weak_alias (__scalblnl, scalblnl)