From ec69debcb977d6395f9e91ee20133de473484e20 Mon Sep 17 00:00:00 2001 From: Andoni Arregi Date: Fri, 11 Feb 2022 12:16:00 +0100 Subject: [PATCH] Improve lgammaf range for very small cases The original cut for small arguments at |x|<2**-70 (copied from the double version) produces that when computing nadj we get a subnormal number for t*x and thus, the division of pi/subnormal will be INF and the logarithm of it too, which is wrong as a result for lgammaf in this range. The proposed new limit seems to be safe and has been tested to produce accurate results. (Courtesy of Andreas Jung, ESA) --- newlib/libm/math/erf_lgamma.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/newlib/libm/math/erf_lgamma.c b/newlib/libm/math/erf_lgamma.c index f88f63092..84d02159b 100644 --- a/newlib/libm/math/erf_lgamma.c +++ b/newlib/libm/math/erf_lgamma.c @@ -168,7 +168,7 @@ static float zero= 0.0000000000e+00; *signgamp = -1; return one/(x-x); } - if(ix<0x1c800000) { /* |x|<2**-70, return -log(|x|) */ + if(ix<0x30800000) { /* |x|<2**-30, return -log(|x|) */ if(hx<0) { *signgamp = -1; return -__ieee754_logf(-x);