66 lines
1.3 KiB
C
66 lines
1.3 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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ADD TWO FLOATS - DOUBLE
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*/
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#include "FP_types.h"
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_double
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adf8(s2,s1)
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_double s1,s2;
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{
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EXTEND e1,e2;
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short swap;
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if (s1.__double[0] == 0 && s1.__double[1] == 0) {
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s1 = s2;
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return s1;
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}
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if (s2.__double[0] == 0 && s2.__double[1] == 0) {
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return s1;
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}
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extend(&s1,&e1,sizeof(_double));
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extend(&s2,&e2,sizeof(_double));
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#ifdef PRT_EXT
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prt_ext("ADF8: e1",&e1);
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prt_ext("ADF8: e2",&e2);
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#endif
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/* adjust mantissas to equal powers */
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if (e1.sign ^ e2.sign) { /* signs are different */
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/* determine which is largest number */
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swap = (e2.exp > e1.exp) ? 1 : (e2.exp < e1.exp) ? 0 :
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(e2.m1 > e1.m1 ) ? 1 : (e2.m1 < e1.m1 ) ? 0 :
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(e2.m2 > e1.m2 ) ? 1 : 0;
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/* adjust mantissas to equal powers */
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sft_ext(&e1,&e2);
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/* subtract the extended formats */
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if (swap) { /* &e2 is the largest number */
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#ifdef PRT_EXT
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fprintf(stderr,"ADF8: swaps and subtracts extended\n");
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#endif
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sub_ext(&e2,&e1);
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e1 = e2;
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}
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else {
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sub_ext(&e1,&e2);
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}
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}
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else {
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/* adjust mantissas to equal powers */
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sft_ext(&e1,&e2);
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add_ext(&e1,&e2);
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}
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#ifdef PRT_EXT
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prt_ext("ADF8: e1 result",&e1);
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#endif
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compact(&e1,&s1,sizeof(_double));
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return(s1);
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}
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