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math: fix exception behaviour of expm1l.c on inf and nan

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This commit is contained in:
Szabolcs Nagy 2012-11-12 23:41:48 +01:00
parent b03c19a4b9
commit 6f64505df3
1 changed files with 7 additions and 13 deletions
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20
src/math/expm1l.c
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@ -44,13 +44,7 @@
* *
* Relative error: * Relative error:
* arithmetic domain # trials peak rms * arithmetic domain # trials peak rms
* IEEE -45,+MAXLOG 200,000 1.2e-19 2.5e-20 * IEEE -45,+maxarg 200,000 1.2e-19 2.5e-20
*
* ERROR MESSAGES:
*
* message condition value returned
* expm1l overflow x > MAXLOG MAXNUM
*
*/ */
#include "libm.h" #include "libm.h"
@ -61,7 +55,6 @@ long double expm1l(long double x)
return expm1(x); return expm1(x);
} }
#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384 #elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
static const long double MAXLOGL = 1.1356523406294143949492E4L;
/* exp(x) - 1 = x + 0.5 x^2 + x^3 P(x)/Q(x) /* exp(x) - 1 = x + 0.5 x^2 + x^3 P(x)/Q(x)
-.5 ln 2 < x < .5 ln 2 -.5 ln 2 < x < .5 ln 2
@ -83,19 +76,20 @@ C1 = 6.93145751953125E-1L,
C2 = 1.428606820309417232121458176568075500134E-6L, C2 = 1.428606820309417232121458176568075500134E-6L,
/* ln 2^-65 */ /* ln 2^-65 */
minarg = -4.5054566736396445112120088E1L, minarg = -4.5054566736396445112120088E1L,
huge = 0x1p10000L; /* ln 2^16384 */
maxarg = 1.1356523406294143949492E4L;
long double expm1l(long double x) long double expm1l(long double x)
{ {
long double px, qx, xx; long double px, qx, xx;
int k; int k;
/* Overflow. */ if (isnan(x))
if (x > MAXLOGL) return x;
return huge*huge; /* overflow */ if (x > maxarg)
return x*0x1p16383L; /* overflow, unless x==inf */
if (x == 0.0) if (x == 0.0)
return x; return x;
/* Minimum value.*/
if (x < minarg) if (x < minarg)
return -1.0; return -1.0;