Author: kargl Date: Mon Jun 3 17:51:08 2013 New Revision: 251327 URL: http://svnweb.freebsd.org/changeset/base/251327
Log: Introduce the macro LOG2_INTERVAL, which is log2(number of intervals). Use the macroi as a micro-optimization to convert a subtraction and division to a shift. Obtained from: bde Modified: head/lib/msun/ld128/s_expl.c head/lib/msun/ld80/s_expl.c Modified: head/lib/msun/ld128/s_expl.c ============================================================================== --- head/lib/msun/ld128/s_expl.c Mon Jun 3 17:41:11 2013 (r251326) +++ head/lib/msun/ld128/s_expl.c Mon Jun 3 17:51:08 2013 (r251327) @@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$"); #include "math_private.h" #define INTERVALS 128 +#define LOG2_INTERVALS 7 #define BIAS (LDBL_MAX_EXP - 1) static volatile const long double tiny = 0x1p-10000L; @@ -229,7 +230,7 @@ expl(long double x) fn = x * INV_L + 0x1.8p112 - 0x1.8p112; n = (int)fn; n2 = (unsigned)n % INTERVALS; - k = (n - n2) / INTERVALS; + k = n >> LOG2_INTERVALS; r1 = x - fn * L1; r2 = -fn * L2; Modified: head/lib/msun/ld80/s_expl.c ============================================================================== --- head/lib/msun/ld80/s_expl.c Mon Jun 3 17:41:11 2013 (r251326) +++ head/lib/msun/ld80/s_expl.c Mon Jun 3 17:51:08 2013 (r251327) @@ -50,6 +50,7 @@ __FBSDID("$FreeBSD$"); #include "math_private.h" #define INTERVALS 128 +#define LOG2_INTERVALS 7 #define BIAS (LDBL_MAX_EXP - 1) static const long double @@ -269,7 +270,8 @@ expl(long double x) n = (int)fn; #endif n2 = (unsigned)n % INTERVALS; - k = (n - n2) / INTERVALS; + /* Depend on the sign bit being propagated: */ + k = n >> LOG2_INTERVALS; r1 = x - fn * L1; r2 = -fn * L2; _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"