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authorRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
committerRoland McGrath <roland@gnu.org>1996-03-05 21:41:30 +0000
commitf7eac6eb504f4baf13dbb4d26717942df050ebe6 (patch)
tree95ff129c06c7f6f246a5e2bfa489ba6382659d19 /sysdeps/libm-ieee754/e_expf.c
parent1521668f2afae1dc2ef5d7ffaeb84353b36874dd (diff)
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Mon Mar 4 20:54:40 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de>
	* Makeconfig ($(common-objpfx)config.make): Depend on config.h.in.


Mon Mar  4 17:35:09 1996  Roland McGrath  <roland@charlie-brown.gnu.ai.mit.edu>

	* hurd/catch-signal.c (hurd_safe_memmove): New function.
	(hurd_safe_copyin, hurd_safe_copyout): New functions.
	* hurd/hurd/sigpreempt.h: Declare them.

Sun Mar  3 08:43:44 1996  Roland McGrath  <roland@charlie-brown.gnu.ai.mit.edu>

	Replace math code with fdlibm from Sun as modified for netbsd by
	JT Conklin and Ian Taylor, including x86 FPU support.
	* sysdeps/libm-ieee754, sysdeps/libm-i387: New directories.
	* math/math_private.h: New file.
	* sysdeps/i386/fpu/Implies: New file.
	* sysdeps/ieee754/Implies: New file.
	* math/machine/asm.h, math/machine/endian.h: New files.
	* math/Makefile, math/math.h: Rewritten.
	* mathcalls.h, math/mathcalls.h: New file, broken out of math.h.
	* math/finite.c: File removed.
	* sysdeps/generic/Makefile [$(subdir)=math]: Frobnication removed.

	* math/test-math.c: Include errno.h and string.h.

	* sysdeps/unix/bsd/dirstream.h: File removed.
	* sysdeps/unix/bsd/readdir.c: File removed.
Diffstat (limited to 'sysdeps/libm-ieee754/e_expf.c')
-rw-r--r--sysdeps/libm-ieee754/e_expf.c104
1 files changed, 104 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_expf.c b/sysdeps/libm-ieee754/e_expf.c
new file mode 100644
index 0000000000..80af17918f
--- /dev/null
+++ b/sysdeps/libm-ieee754/e_expf.c
@@ -0,0 +1,104 @@
+/* e_expf.c -- float version of e_exp.c.
+ * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
+ */
+
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+#if defined(LIBM_SCCS) && !defined(lint)
+static char rcsid[] = "$NetBSD: e_expf.c,v 1.5 1995/05/10 20:45:05 jtc Exp $";
+#endif
+
+#include "math.h"
+#include "math_private.h"
+
+static const volatile float huge = 1.0e+30;
+
+#ifdef __STDC__
+static const float
+#else
+static float
+#endif
+one	= 1.0,
+halF[2]	= {0.5,-0.5,},
+twom100 = 7.8886090522e-31,      /* 2**-100=0x0d800000 */
+o_threshold=  8.8721679688e+01,  /* 0x42b17180 */
+u_threshold= -1.0397208405e+02,  /* 0xc2cff1b5 */
+ln2HI[2]   ={ 6.9313812256e-01,		/* 0x3f317180 */
+	     -6.9313812256e-01,},	/* 0xbf317180 */
+ln2LO[2]   ={ 9.0580006145e-06,  	/* 0x3717f7d1 */
+	     -9.0580006145e-06,},	/* 0xb717f7d1 */
+invln2 =  1.4426950216e+00, 		/* 0x3fb8aa3b */
+P1   =  1.6666667163e-01, /* 0x3e2aaaab */
+P2   = -2.7777778450e-03, /* 0xbb360b61 */
+P3   =  6.6137559770e-05, /* 0x388ab355 */
+P4   = -1.6533901999e-06, /* 0xb5ddea0e */
+P5   =  4.1381369442e-08; /* 0x3331bb4c */
+
+#ifdef __STDC__
+	float __ieee754_expf(float x)	/* default IEEE double exp */
+#else
+	float __ieee754_expf(x)	/* default IEEE double exp */
+	float x;
+#endif
+{
+	float y,hi,lo,c,t;
+	int32_t k,xsb;
+	u_int32_t hx;
+
+	GET_FLOAT_WORD(hx,x);
+	xsb = (hx>>31)&1;		/* sign bit of x */
+	hx &= 0x7fffffff;		/* high word of |x| */
+
+    /* filter out non-finite argument */
+	if(hx >= 0x42b17218) {			/* if |x|>=88.721... */
+	    if(hx>0x7f800000)
+		 return x+x;	 		/* NaN */
+            if(hx==0x7f800000)
+		return (xsb==0)? x:0.0;		/* exp(+-inf)={inf,0} */
+	    if(x > o_threshold) return huge*huge; /* overflow */
+	    if(x < u_threshold) return twom100*twom100; /* underflow */
+	}
+
+    /* argument reduction */
+	if(hx > 0x3eb17218) {		/* if  |x| > 0.5 ln2 */ 
+	    if(hx < 0x3F851592) {	/* and |x| < 1.5 ln2 */
+		hi = x-ln2HI[xsb]; lo=ln2LO[xsb]; k = 1-xsb-xsb;
+	    } else {
+		k  = invln2*x+halF[xsb];
+		t  = k;
+		hi = x - t*ln2HI[0];	/* t*ln2HI is exact here */
+		lo = t*ln2LO[0];
+	    }
+	    x  = hi - lo;
+	} 
+	else if(hx < 0x31800000)  {	/* when |x|<2**-28 */
+	    if(huge+x>one) return one+x;/* trigger inexact */
+	}
+	else k = 0;
+
+    /* x is now in primary range */
+	t  = x*x;
+	c  = x - t*(P1+t*(P2+t*(P3+t*(P4+t*P5))));
+	if(k==0) 	return one-((x*c)/(c-(float)2.0)-x); 
+	else 		y = one-((lo-(x*c)/((float)2.0-c))-hi);
+	if(k >= -125) {
+	    u_int32_t hy;
+	    GET_FLOAT_WORD(hy,y);
+	    SET_FLOAT_WORD(y,hy+(k<<23));	/* add k to y's exponent */
+	    return y;
+	} else {
+	    u_int32_t hy;
+	    GET_FLOAT_WORD(hy,y);
+	    SET_FLOAT_WORD(y,hy+((k+100)<<23));	/* add k to y's exponent */
+	    return y*twom100;
+	}
+}