1 files changed, 70 insertions, 0 deletions
diff --git a/gdtoa/ulp.c b/gdtoa/ulp.c
new file mode 100644
index 00000000..7810a5c8
--- /dev/null
+++ b/gdtoa/ulp.c
@@ -0,0 +1,70 @@
+/****************************************************************
+
+The author of this software is David M. Gay.
+
+Copyright (C) 1998, 1999 by Lucent Technologies
+All Rights Reserved
+
+Permission to use, copy, modify, and distribute this software and
+its documentation for any purpose and without fee is hereby
+granted, provided that the above copyright notice appear in all
+copies and that both that the copyright notice and this
+permission notice and warranty disclaimer appear in supporting
+documentation, and that the name of Lucent or any of its entities
+not be used in advertising or publicity pertaining to
+distribution of the software without specific, written prior
+permission.
+
+LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
+IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
+SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
+IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
+THIS SOFTWARE.
+
+****************************************************************/
+
+/* Please send bug reports to David M. Gay (dmg at acm dot org,
+ * with " at " changed at "@" and " dot " changed to ".").	*/
+
+#include "gdtoaimp.h"
+
+ double
+ulp
+#ifdef KR_headers
+	(x) double x;
+#else
+	(double x)
+#endif
+{
+	Long L;
+	double a;
+
+	L = (word0(x) & Exp_mask) - (P-1)*Exp_msk1;
+#ifndef Sudden_Underflow
+	if (L > 0) {
+#endif
+#ifdef IBM
+		L |= Exp_msk1 >> 4;
+#endif
+		word0(a) = L;
+		word1(a) = 0;
+#ifndef Sudden_Underflow
+		}
+	else {
+		L = -L >> Exp_shift;
+		if (L < Exp_shift) {
+			word0(a) = 0x80000 >> L;
+			word1(a) = 0;
+			}
+		else {
+			word0(a) = 0;
+			L -= Exp_shift;
+			word1(a) = L >= 31 ? 1 : 1 << 31 - L;
+			}
+		}
+#endif
+	return a;
+	}