Initial import of David Gay's gdtoa library for conversion between

strings and floating point.

1 files changed, 104 insertions, 0 deletions

diff --git a/contrib/gdtoa/sum.c b/contrib/gdtoa/sum.c
new file mode 100644
index 0000000..1e1a4de
--- /dev/null
+++ b/contrib/gdtoa/sum.c
@@ -0,0 +1,104 @@
+/****************************************************************
+
+The author of this software is David M. Gay.
+
+Copyright (C) 1998 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
+	Bell Laboratories, Room 2C-463
+	600 Mountain Avenue
+	Murray Hill, NJ 07974-0636
+	U.S.A.
+	dmg@bell-labs.com
+ */
+
+#include "gdtoaimp.h"
+
+ Bigint *
+#ifdef KR_headers
+sum(a, b) Bigint *a; Bigint *b;
+#else
+sum(Bigint *a, Bigint *b)
+#endif
+{
+	Bigint *c;
+	ULong carry, *xc, *xa, *xb, *xe, y;
+#ifdef Pack_32
+	ULong z;
+#endif
+
+	if (a->wds < b->wds) {
+		c = b; b = a; a = c;
+		}
+	c = Balloc(a->k);
+	c->wds = a->wds;
+	carry = 0;
+	xa = a->x;
+	xb = b->x;
+	xc = c->x;
+	xe = xc + b->wds;
+#ifdef Pack_32
+	do {
+		y = (*xa & 0xffff) + (*xb & 0xffff) + carry;
+		carry = (y & 0x10000) >> 16;
+		z = (*xa++ >> 16) + (*xb++ >> 16) + carry;
+		carry = (z & 0x10000) >> 16;
+		Storeinc(xc, z, y);
+		}
+		while(xc < xe);
+	xe += a->wds - b->wds;
+	while(xc < xe) {
+		y = (*xa & 0xffff) + carry;
+		carry = (y & 0x10000) >> 16;
+		z = (*xa++ >> 16) + carry;
+		carry = (z & 0x10000) >> 16;
+		Storeinc(xc, z, y);
+		}
+#else
+	do {
+		y = *xa++ + *xb++ + carry;
+		carry = (y & 0x10000) >> 16;
+		*xc++ = y & 0xffff;
+		}
+		while(xc < xe);
+	xe += a->wds - b->wds;
+	while(xc < xe) {
+		y = *xa++ + carry;
+		carry = (y & 0x10000) >> 16;
+		*xc++ = y & 0xffff;
+		}
+#endif
+	if (carry) {
+		if (c->wds == c->maxwds) {
+			b = Balloc(c->k + 1);
+			Bcopy(b, c);
+			Bfree(c);
+			c = b;
+			}
+		c->x[c->wds++] = 1;
+		}
+	return c;
+	}