test some basic operations with subnomal numbers

regress/lib/libc/ieeefp/Makefile

@@ -1,7 +1,7 @@
-#	$NetBSD: Makefile,v 1.13 2003/10/24 21:25:20 kleink Exp $
+#	$NetBSD: Makefile,v 1.14 2006/02/21 16:36:57 drochner Exp $
 
 # Don't hook up testfloat just yet. (ross, 2001.3.12)
 
-SUBDIR+= except infinity nan round
+SUBDIR+= except infinity nan round subnormal
 
 .include <bsd.subdir.mk>

regress/lib/libc/ieeefp/subnormal/Makefile

@@ -0,0 +1,13 @@
+# $NetBSD: Makefile,v 1.1 2006/02/21 16:36:57 drochner Exp $
+
+NOMAN=		# defined
+
+PROG=		subnormal
+LDADD+=		-lm
+
+#CPPFLAGS+=	-DUSE_FLOAT
+
+regress: ${PROG}
+	./${PROG}
+
+.include <bsd.prog.mk>

regress/lib/libc/ieeefp/subnormal/subnormal.c

@@ -0,0 +1,71 @@
+/* $NetBSD: subnormal.c,v 1.1 2006/02/21 16:36:57 drochner Exp $ */
+#include <math.h>
+#include <float.h>
+#include <assert.h>
+
+#ifdef USE_FLOAT
+#define FPTYPE float
+#define FPTYPE_MIN FLT_MIN
+#define FPTYPE_MIN_EXP FLT_MIN_EXP
+#define FPTYPE_MANT_DIG FLT_MANT_DIG
+#define LDEXP(d,e) ldexpf(d,e)
+#define MODF(d,ip) modff(d,ip)
+#define FREXP(d,e) frexpf(d,e)
+#else
+#ifdef USE_LONGDOUBLE
+#define FPTYPE long double
+#define FPTYPE_MIN LDBL_MIN
+#define FPTYPE_MIN_EXP LDBL_MIN_EXP
+#define FPTYPE_MANT_DIG LDBL_MANT_DIG
+#define LDEXP(d,e) ldexpl(d,e)
+#define MODF(d,ip) modfl(d,ip)
+#define FREXP(d,e) frexpl(d,e)
+#else
+#define FPTYPE double
+#define FPTYPE_MIN DBL_MIN
+#define FPTYPE_MIN_EXP DBL_MIN_EXP
+#define FPTYPE_MANT_DIG DBL_MANT_DIG
+#define LDEXP(d,e) ldexp(d,e)
+#define MODF(d,ip) modf(d,ip)
+#define FREXP(d,e) frexp(d,e)
+#endif
+#endif
+
+int
+main()
+{
+	FPTYPE d0, d1, d2, f, ip;
+	int e, i;
+
+	d0 = FPTYPE_MIN;
+	assert(fpclassify(d0) == FP_NORMAL);
+	f = FREXP(d0, &e);
+	assert(e == FPTYPE_MIN_EXP);
+	assert(f == 0.5);
+	d1 = d0;
+
+	/* shift a "1" bit through the mantissa (skip the implicit bit) */
+	for (i = 1; i < FPTYPE_MANT_DIG; i++) {
+		d1 /= 2;
+		assert(fpclassify(d1) == FP_SUBNORMAL);
+		assert(d1 > 0 && d1 < d0);
+
+		d2 = LDEXP(d0, -i);
+		assert(d2 == d1);
+		d2 = MODF(d1, &ip);
+		assert(d2 == d1);
+		assert(ip == 0);
+
+		f = FREXP(d1, &e);
+		assert(e == FPTYPE_MIN_EXP - i);
+		assert(f == 0.5);
+	}
+
+	d1 /= 2;
+	assert(fpclassify(d1) == FP_ZERO);
+	f = FREXP(d1, &e);
+	assert(e == 0);
+	assert(f == 0);
+
+	return (0);
+}