79 lines
1.7 KiB
C
79 lines
1.7 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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/*
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NORMALIZE an EXTENDED FORMAT NUMBER
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*/
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/********************************************************/
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#include "FP_shift.h"
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#include "FP_types.h"
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nrm_ext(e1)
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EXTEND *e1;
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{
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register unsigned long *mant_1;
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register unsigned long *mant_2;
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/* local CAST conversion */
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#ifdef PRT_EXT
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prt_ext("before NRM_EXT() e1:",e1);
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#endif PRT_EXT
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mant_1 = (unsigned long *) &e1->m1;
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/*
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THIS RESULTS IN A BAD CODE !!!!
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ANOTHER BUG IN EM CODE MAYBE????
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mant_2 = (unsigned long *) &e1->m2;
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*/
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/* statement that works */
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mant_2 = mant_1 + 1;
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/* we assume that the mantissa != 0 */
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/* if it is then just return */
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/* to let it be a problem elsewhere */
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/* THAT IS, The exponent is not set to */
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/* zero. If we don't test here an */
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/* infinite loop is generated when */
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/* mantissa is zero */
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if ((*mant_1 | *mant_2) == 0L)
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return;
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/* if top word is zero mov low word */
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/* to top word, adjust exponent value */
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if (*mant_1 == 0L) {
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*mant_1++ = e1->m2;
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*mant_1-- = 0L;
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e1->exp -= 32;
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}
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#ifdef OLD
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/* check that e1->m1 is not too large */
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if (*mant_1 & CARRYBIT) { /* carry occured */
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e1->exp++; /* increase exponent */
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*mant_2 >>= 1; /* right shift mantissa */
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if ((short) *mant_1 & 01)
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*mant_2 |= CARRYBIT;
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*mant_1 >>= 1;
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}
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#endif
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while ((*mant_1 & NORMBIT) == 0) {
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e1->exp--;
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*mant_1 <<= 1;
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if ((*mant_2 & CARRYBIT) == 0)
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; /* empty statement */
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else {
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*mant_1 += 1;
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}
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*mant_2 <<= 1;
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}
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#ifdef PRT_EXT
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prt_ext("after NRM_EXT() e1:",e1);
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#endif PRT_EXT
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}
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