Initial revision

lib/float/adder.c

@@ -0,0 +1,50 @@
+/*
+  (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
+  See the copyright notice in the ACK home directory, in the file "Copyright".
+*/
+
+/* $Header$ */
+
+/*
+ *	these are the routines the routines to do 32 and  64-bit addition
+ */
+
+# ifdef	EXT_DEBUG
+# include <stdio.h>
+# endif
+
+# include "FP_types.h"
+# define	UNKNOWN -1
+# define	TRUE	 1
+# define	FALSE	 0
+# define	MAXBIT	0x80000000L
+
+	/*
+	 *	add 64 bits
+	 */
+int
+b64_add(e1,e2)
+		/*
+		 * pointers to 64 bit 'registers'
+		 */
+register	B64	*e1,*e2;
+{
+		register	int	overflow;
+				int	carry;
+
+			/* add higher pair of 32 bits */
+	overflow = ((unsigned long) 0xFFFFFFFF - e1->h_32 < e2->h_32);
+	e1->h_32 += e2->h_32;
+
+			/* add lower pair of 32 bits */
+	carry = ((unsigned long) 0xFFFFFFFF - e1->l_32 < e2->l_32);
+	e1->l_32 += e2->l_32;
+# ifdef	EXT_DEBUG
+	printf("\t\t\t\t\tb64_add: overflow (%d); internal carry(%d)\n",
+					overflow,carry);
+	fflush(stdout);
+# endif
+	if ((carry) && (++e1->h_32 == 0))
+		return(TRUE);		/* had a 64 bit overflow */
+	return(overflow);		/* return status from higher add */
+}