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