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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_fmodf.c
parent1521668f2afae1dc2ef5d7ffaeb84353b36874dd (diff)
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_fmodf.c')
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1 files changed, 113 insertions, 0 deletions
diff --git a/sysdeps/libm-ieee754/e_fmodf.c b/sysdeps/libm-ieee754/e_fmodf.c
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+/* e_fmodf.c -- float version of e_fmod.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_fmodf.c,v 1.4 1995/05/10 20:45:10 jtc Exp $";
+#endif
+
+/*
+ * __ieee754_fmodf(x,y)
+ * Return x mod y in exact arithmetic
+ * Method: shift and subtract
+ */
+
+#include "math.h"
+#include "math_private.h"
+
+#ifdef __STDC__
+static const float one = 1.0, Zero[] = {0.0, -0.0,};
+#else
+static float one = 1.0, Zero[] = {0.0, -0.0,};
+#endif
+
+#ifdef __STDC__
+ float __ieee754_fmodf(float x, float y)
+#else
+ float __ieee754_fmodf(x,y)
+ float x,y ;
+#endif
+{
+ int32_t n,hx,hy,hz,ix,iy,sx,i;
+
+ GET_FLOAT_WORD(hx,x);
+ GET_FLOAT_WORD(hy,y);
+ sx = hx&0x80000000; /* sign of x */
+ hx ^=sx; /* |x| */
+ hy &= 0x7fffffff; /* |y| */
+
+ /* purge off exception values */
+ if(hy==0||(hx>=0x7f800000)|| /* y=0,or x not finite */
+ (hy>0x7f800000)) /* or y is NaN */
+ return (x*y)/(x*y);
+ if(hx<hy) return x; /* |x|<|y| return x */
+ if(hx==hy)
+ return Zero[(u_int32_t)sx>>31]; /* |x|=|y| return x*0*/
+
+ /* determine ix = ilogb(x) */
+ if(hx<0x00800000) { /* subnormal x */
+ for (ix = -126,i=(hx<<8); i>0; i<<=1) ix -=1;
+ } else ix = (hx>>23)-127;
+
+ /* determine iy = ilogb(y) */
+ if(hy<0x00800000) { /* subnormal y */
+ for (iy = -126,i=(hy<<8); i>=0; i<<=1) iy -=1;
+ } else iy = (hy>>23)-127;
+
+ /* set up {hx,lx}, {hy,ly} and align y to x */
+ if(ix >= -126)
+ hx = 0x00800000|(0x007fffff&hx);
+ else { /* subnormal x, shift x to normal */
+ n = -126-ix;
+ hx = hx<<n;
+ }
+ if(iy >= -126)
+ hy = 0x00800000|(0x007fffff&hy);
+ else { /* subnormal y, shift y to normal */
+ n = -126-iy;
+ hy = hy<<n;
+ }
+
+ /* fix point fmod */
+ n = ix - iy;
+ while(n--) {
+ hz=hx-hy;
+ if(hz<0){hx = hx+hx;}
+ else {
+ if(hz==0) /* return sign(x)*0 */
+ return Zero[(u_int32_t)sx>>31];
+ hx = hz+hz;
+ }
+ }
+ hz=hx-hy;
+ if(hz>=0) {hx=hz;}
+
+ /* convert back to floating value and restore the sign */
+ if(hx==0) /* return sign(x)*0 */
+ return Zero[(u_int32_t)sx>>31];
+ while(hx<0x00800000) { /* normalize x */
+ hx = hx+hx;
+ iy -= 1;
+ }
+ if(iy>= -126) { /* normalize output */
+ hx = ((hx-0x00800000)|((iy+127)<<23));
+ SET_FLOAT_WORD(x,hx|sx);
+ } else { /* subnormal output */
+ n = -126 - iy;
+ hx >>= n;
+ SET_FLOAT_WORD(x,hx|sx);
+ x *= one; /* create necessary signal */
+ }
+ return x; /* exact output */
+}