Print this page
11210 libm should be cstyle(1ONBLD) clean
@@ -20,18 +20,19 @@
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
+
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak __hypot = hypot
-/* INDENT OFF */
+
/*
* Hypot(x, y)
* by K.C. Ng for SUN 4.0 libm, updated 3/11/2003.
* Method :
* A. When rounding is rounded-to-nearest:
@@ -64,29 +65,29 @@
* (units in the last place)
*/
#include "libm.h"
-static const double
- zero = 0.0,
+static const double zero = 0.0,
onep1u = 1.00000000000000022204e+00, /* 0x3ff00000 1 = 1+2**-52 */
twom53 = 1.11022302462515654042e-16, /* 0x3ca00000 0 = 2**-53 */
twom768 = 6.441148769597133308e-232, /* 2^-768 */
two768 = 1.552518092300708935e+231; /* 2^768 */
-/* INDENT ON */
double
-hypot(double x, double y) {
+hypot(double x, double y)
+{
double xh, yh, w, ax, ay;
int i, j, nx, ny, ix, iy, iscale = 0;
unsigned lx, ly;
- ix = ((int *) &x)[HIWORD] & ~0x80000000;
- lx = ((int *) &x)[LOWORD];
- iy = ((int *) &y)[HIWORD] & ~0x80000000;
- ly = ((int *) &y)[LOWORD];
+ ix = ((int *)&x)[HIWORD] & ~0x80000000;
+ lx = ((int *)&x)[LOWORD];
+ iy = ((int *)&y)[HIWORD] & ~0x80000000;
+ ly = ((int *)&y)[LOWORD];
+
/*
* Force ax = |x| ~>~ ay = |y|
*/
if (iy > ix) {
ax = fabs(y);
@@ -99,13 +100,15 @@
ly = i;
} else {
ax = fabs(x);
ay = fabs(y);
}
+
nx = ix >> 20;
ny = iy >> 20;
j = nx - ny;
+
/*
* x >= 2^500 (x*x or y*y may overflow)
*/
if (nx >= 0x5f3) {
if (nx == 0x7ff) { /* inf or NaN, signal of sNaN */
@@ -116,95 +119,119 @@
else
return (ax * ay); /* + -> * for Cheetah */
} else if (j > 32) { /* x >> y */
if (j <= 53)
ay *= twom53;
+
ax += ay;
- if (((int *) &ax)[HIWORD] == 0x7ff00000)
+
+ if (((int *)&ax)[HIWORD] == 0x7ff00000)
ax = _SVID_libm_err(x, y, 4);
+
return (ax);
}
+
ax *= twom768;
ay *= twom768;
iscale = 2;
ix -= 768 << 20;
iy -= 768 << 20;
}
+
/*
* y < 2^-450 (x*x or y*y may underflow)
*/
else if (ny < 0x23d) {
if ((ix | lx) == 0)
return (ay);
+
if ((iy | ly) == 0)
return (ax);
+
if (j > 53) /* x >> y */
return (ax + ay);
+
iscale = 1;
ax *= two768;
ay *= two768;
+
if (nx == 0) {
if (ax == zero) /* guard subnormal flush to zero */
return (ax);
- ix = ((int *) &ax)[HIWORD];
- } else
+
+ ix = ((int *)&ax)[HIWORD];
+ } else {
ix += 768 << 20;
+ }
+
if (ny == 0) {
if (ay == zero) /* guard subnormal flush to zero */
return (ax * twom768);
- iy = ((int *) &ay)[HIWORD];
- } else
+
+ iy = ((int *)&ay)[HIWORD];
+ } else {
iy += 768 << 20;
+ }
+
j = (ix >> 20) - (iy >> 20);
+
if (j > 32) { /* x >> y */
if (j <= 53)
ay *= twom53;
+
return ((ax + ay) * twom768);
}
} else if (j > 32) { /* x >> y */
if (j <= 53)
ay *= twom53;
+
return (ax + ay);
}
+
/*
* Medium range ax and ay with max{|ax/ay|,|ay/ax|} bounded by 2^32
* First check rounding mode by comparing onep1u*onep1u with onep1u+twom53.
* Make sure the computation is done at run-time.
*/
if (((lx | ly) << 5) == 0) {
ay = ay * ay;
ax += ay / (ax + sqrt(ax * ax + ay));
- } else
- if (onep1u * onep1u != onep1u + twom53) {
- /* round-to-zero, positive, negative mode */
- /* magic formula with less than an ulp error */
+ } else if (onep1u * onep1u != onep1u + twom53) {
+ /*
+ * round-to-zero, positive, negative mode
+ * magic formula with less than an ulp error
+ */
w = sqrt(ax * ax + ay * ay);
ax += ay / ((ax + w) / ay);
} else {
/* round-to-nearest mode */
w = ax - ay;
+
if (w > ay) {
- ((int *) &xh)[HIWORD] = ix;
- ((int *) &xh)[LOWORD] = 0;
+ ((int *)&xh)[HIWORD] = ix;
+ ((int *)&xh)[LOWORD] = 0;
ay = ay * ay + (ax - xh) * (ax + xh);
ax = sqrt(xh * xh + ay);
} else {
ax = ax + ax;
- ((int *) &xh)[HIWORD] = ix + 0x00100000;
- ((int *) &xh)[LOWORD] = 0;
- ((int *) &yh)[HIWORD] = iy;
- ((int *) &yh)[LOWORD] = 0;
+ ((int *)&xh)[HIWORD] = ix + 0x00100000;
+ ((int *)&xh)[LOWORD] = 0;
+ ((int *)&yh)[HIWORD] = iy;
+ ((int *)&yh)[LOWORD] = 0;
ay = w * w + ((ax - xh) * yh + (ay - yh) * ax);
ax = sqrt(xh * yh + ay);
}
}
+
if (iscale > 0) {
- if (iscale == 1)
+ if (iscale == 1) {
ax *= twom768;
- else {
+ } else {
ax *= two768; /* must generate side effect here */
- if (((int *) &ax)[HIWORD] == 0x7ff00000)
+
+ if (((int *)&ax)[HIWORD] == 0x7ff00000)
ax = _SVID_libm_err(x, y, 4);
}
}
+
return (ax);
}