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authornsz <nsz@port70.net>2012-03-19 19:26:31 +0100
committernsz <nsz@port70.net>2012-03-19 19:26:31 +0100
commit2e8c8fbe7d65ba0026cb084dc8570d94cbc908ff (patch)
tree59b2813cfc9f1e2d36d80d6c8b39c404fc9cdbe7 /src/math/__rem_pio2l.c
parentc3587effe27a3ac8c1406f064b7705963be9887a (diff)
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don't inline __rem_pio2l so the code size is smaller
Diffstat (limited to 'src/math/__rem_pio2l.c')
-rw-r--r--src/math/__rem_pio2l.c131
1 files changed, 131 insertions, 0 deletions
diff --git a/src/math/__rem_pio2l.c b/src/math/__rem_pio2l.c
new file mode 100644
index 00000000..10af404c
--- /dev/null
+++ b/src/math/__rem_pio2l.c
@@ -0,0 +1,131 @@
+/* origin: FreeBSD /usr/src/lib/msun/ld80/e_rem_pio2.c */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ * Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ *
+ * Optimized by Bruce D. Evans.
+ */
+#include "libm.h"
+#if LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
+/* ld80 version of __rem_pio2(x,y)
+ *
+ * return the remainder of x rem pi/2 in y[0]+y[1]
+ * use __rem_pio2_large() for large x
+ */
+
+#define BIAS (LDBL_MAX_EXP - 1)
+
+/*
+ * invpio2: 64 bits of 2/pi
+ * pio2_1: first 39 bits of pi/2
+ * pio2_1t: pi/2 - pio2_1
+ * pio2_2: second 39 bits of pi/2
+ * pio2_2t: pi/2 - (pio2_1+pio2_2)
+ * pio2_3: third 39 bits of pi/2
+ * pio2_3t: pi/2 - (pio2_1+pio2_2+pio2_3)
+ */
+static const double
+zero = 0.00000000000000000000e+00, /* 0x00000000, 0x00000000 */
+two24 = 1.67772160000000000000e+07, /* 0x41700000, 0x00000000 */
+pio2_1 = 1.57079632679597125389e+00, /* 0x3FF921FB, 0x54444000 */
+pio2_2 = -1.07463465549783099519e-12, /* -0x12e7b967674000.0p-92 */
+pio2_3 = 6.36831716351370313614e-25; /* 0x18a2e037074000.0p-133 */
+
+static const long double
+invpio2 = 6.36619772367581343076e-01L, /* 0xa2f9836e4e44152a.0p-64 */
+pio2_1t = -1.07463465549719416346e-12L, /* -0x973dcb3b399d747f.0p-103 */
+pio2_2t = 6.36831716351095013979e-25L, /* 0xc51701b839a25205.0p-144 */
+pio2_3t = -2.75299651904407171810e-37L; /* -0xbb5bf6c7ddd660ce.0p-185 */
+
+int __rem_pio2l(long double x, long double *y)
+{
+ union IEEEl2bits u,u1;
+ long double z,w,t,r,fn;
+ double tx[3],ty[2];
+ int e0,ex,i,j,nx,n;
+ int16_t expsign;
+
+ u.e = x;
+ expsign = u.xbits.expsign;
+ ex = expsign & 0x7fff;
+ if (ex < BIAS + 25 || (ex == BIAS + 25 && u.bits.manh < 0xc90fdaa2)) {
+ union IEEEl2bits u2;
+ int ex1;
+
+ /* |x| ~< 2^25*(pi/2), medium size */
+ /* Use a specialized rint() to get fn. Assume round-to-nearest. */
+ fn = x*invpio2 + 0x1.8p63;
+ fn = fn - 0x1.8p63;
+// FIXME
+//#ifdef HAVE_EFFICIENT_IRINT
+// n = irint(fn);
+//#else
+ n = fn;
+//#endif
+ r = x-fn*pio2_1;
+ w = fn*pio2_1t; /* 1st round good to 102 bit */
+ j = ex;
+ y[0] = r-w;
+ u2.e = y[0];
+ ex1 = u2.xbits.expsign & 0x7fff;
+ i = j-ex1;
+ if (i > 22) { /* 2nd iteration needed, good to 141 */
+ t = r;
+ w = fn*pio2_2;
+ r = t-w;
+ w = fn*pio2_2t-((t-r)-w);
+ y[0] = r-w;
+ u2.e = y[0];
+ ex1 = u2.xbits.expsign & 0x7fff;
+ i = j-ex1;
+ if (i > 61) { /* 3rd iteration need, 180 bits acc */
+ t = r; /* will cover all possible cases */
+ w = fn*pio2_3;
+ r = t-w;
+ w = fn*pio2_3t-((t-r)-w);
+ y[0] = r-w;
+ }
+ }
+ y[1] = (r - y[0]) - w;
+ return n;
+ }
+ /*
+ * all other (large) arguments
+ */
+ if (ex == 0x7fff) { /* x is inf or NaN */
+ y[0] = y[1] = x - x;
+ return 0;
+ }
+ /* set z = scalbn(|x|,ilogb(x)-23) */
+ u1.e = x;
+ e0 = ex - BIAS - 23; /* e0 = ilogb(|x|)-23; */
+ u1.xbits.expsign = ex - e0;
+ z = u1.e;
+ for (i=0; i<2; i++) {
+ tx[i] = (double)(int32_t)z;
+ z = (z-tx[i])*two24;
+ }
+ tx[2] = z;
+ nx = 3;
+ while (tx[nx-1] == zero)
+ nx--; /* skip zero term */
+ n = __rem_pio2_large(tx,ty,e0,nx,2);
+ r = (long double)ty[0] + ty[1];
+ w = ty[1] - (r - ty[0]);
+ if (expsign < 0) {
+ y[0] = -r;
+ y[1] = -w;
+ return -n;
+ }
+ y[0] = r;
+ y[1] = w;
+ return n;
+}
+#endif