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- Correct the range check in the double version to catch negative values

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that would overflow.
- Style fixes and improved handling of NaNs suggested by bde.
This commit is contained in:
David Schultz 2008-01-11 04:18:25 +00:00
parent 9330dbc3a1
commit 73b2958b94
2 changed files with 22 additions and 19 deletions

35
lib/msun/src/s_csqrt.c

@ -41,17 +41,20 @@ __FBSDID("$FreeBSD$");
*/
#pragma STDC CX_LIMITED_RANGE on
/* We risk spurious overflow for components >= DBL_MAX/(1+sqrt(2)) */
#define THRESH 0x1.a827999fcef32p+1022
/* We risk spurious overflow for components >= DBL_MAX / (1 + sqrt(2)). */
#define THRESH 0x1.a827999fcef32p+1022
double complex
csqrt(double complex z)
{
double a = creal(z), b = cimag(z);
double t;
double complex result;
double a, b;
double t;
int scale;
a = creal(z);
b = cimag(z);
/* Handle special cases. */
if (z == 0)
return (cpack(0, b));
@ -59,13 +62,13 @@ csqrt(double complex z)
return (cpack(INFINITY, b));
if (isnan(a)) {
t = (b - b) / (b - b); /* raise invalid if b is not a NaN */
return (cpack(t, t)); /* return NaN + NaN i */
return (cpack(a, t)); /* return NaN + NaN i */
}
if (isinf(a)) {
/*
* csqrt(inf + nan i) = inf + nan i
* csqrt(inf + NaN i) = inf + NaN i
* csqrt(inf + y i) = inf + 0 i
* csqrt(-inf + nan i) = nan +- inf i
* csqrt(-inf + NaN i) = NaN +- inf i
* csqrt(-inf + y i) = 0 + inf i
*/
if (signbit(a))
@ -79,15 +82,15 @@ csqrt(double complex z)
*/
/* Scale to avoid overflow. */
if (a >= THRESH || b >= THRESH) {
a *= 0.25;
b *= 0.25;
scale = 1;
if (fabs(a) >= THRESH || fabs(b) >= THRESH) {
a *= 0.25;
b *= 0.25;
scale = 1;
} else {
scale = 0;
scale = 0;
}
/* Algorithm 312, CACM vol 10, Oct 1967 */
/* Algorithm 312, CACM vol 10, Oct 1967. */
if (a >= 0) {
t = sqrt((a + hypot(a, b)) * 0.5);
result = cpack(t, b / (2 * t));
@ -96,9 +99,9 @@ csqrt(double complex z)
result = cpack(fabs(b) / (2 * t), copysign(t, b));
}
/* Rescale */
/* Rescale. */
if (scale)
return (result * 2);
return (result * 2);
else
return (result);
return (result);
}

6
lib/msun/src/s_csqrtf.c

@ -54,13 +54,13 @@ csqrtf(float complex z)
return (cpackf(INFINITY, b));
if (isnan(a)) {
t = (b - b) / (b - b); /* raise invalid if b is not a NaN */
return (cpackf(t, t)); /* return NaN + NaN i */
return (cpackf(a, t)); /* return NaN + NaN i */
}
if (isinf(a)) {
/*
* csqrtf(inf + nan i) = inf + nan i
* csqrtf(inf + NaN i) = inf + NaN i
* csqrtf(inf + y i) = inf + 0 i
* csqrtf(-inf + nan i) = nan +- inf i
* csqrtf(-inf + NaN i) = NaN +- inf i
* csqrtf(-inf + y i) = 0 + inf i
*/
if (signbit(a))