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t_round.c revision 1.1 
      1 /* $NetBSD: t_round.c,v 1.1 2011/04/08 06:49:21 jruoho Exp $ */
      2 
      3 #include <atf-c.h>
      4 #include <math.h>
      5 
      6 /*
      7  * This tests for a bug in the initial implementation where
      8  * precision was lost in an internal substraction, leading to
      9  * rounding into the wrong direction.
     10  */
     11 
     12 /* 0.5 - EPSILON */
     13 #define VAL	0x0.7ffffffffffffcp0
     14 #define VALF	0x0.7fffff8p0
     15 
     16 ATF_TC(round_dir);
     17 ATF_TC_HEAD(round_dir, tc)
     18 {
     19 	atf_tc_set_md_var(tc, "descr","Check for rounding in wrong direction");
     20 }
     21 
     22 ATF_TC_BODY(round_dir, tc)
     23 {
     24 	double a = VAL, b, c;
     25 	float af = VALF, bf, cf;
     26 
     27 	b = round(a);
     28 	bf = roundf(af);
     29 
     30 	ATF_REQUIRE(fabs(b) < 1.0e-40);
     31 	ATF_REQUIRE(fabsf(bf) < 1.0e-40);
     32 
     33 	c = round(-a);
     34 	cf = roundf(-af);
     35 
     36 	ATF_REQUIRE(fabs(c) < 1.0e-40);
     37 	ATF_REQUIRE(fabsf(cf) < 1.0e-40);
     38 }
     39 
     40 ATF_TP_ADD_TCS(tp)
     41 {
     42 
     43 	ATF_TP_ADD_TC(tp, round_dir);
     44 
     45 	return atf_no_error();
     46 }
     47