56 lines
1.1 KiB
C
56 lines
1.1 KiB
C
/*
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CONVERT INTEGER TO FLOAT
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THIS ROUTINE WORKS BY FILLING AN EXTENDED
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WITH THE INTEGER VALUE IN EXTENDED FORMAT
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AND USES COMPACT() TO PUT IT INTO THE PROPER
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FLOATING POINT PRECISION.
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*/
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#include "FP_types.h"
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_double
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cif8(ss,src)
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int ss; /* source size */
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long src; /* largest possible integer to convert */
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{
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EXTEND buf;
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_double *result; /* for return value */
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short *ipt;
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long i_src;
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result = (_double *) &ss; /* always */
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zrf_ext(&buf);
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if (ss == sizeof(long)) {
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buf.exp = 33;
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i_src = src;
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}
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else {
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ipt = (short *) &src;
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i_src = (long) *ipt;
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buf.exp = 17;
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}
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#ifdef PRT_STDERR
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fprintf(stderr,"CIF8(ds(%d),ss(%d),src(%D))\n\n",8,ss,i_src);
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#endif
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if (i_src == 0) {
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zrf8(result);
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return(*result);
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}
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/* ESTABLISHED THAT src != 0 */
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/* adjust exponent field */
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buf.sign = (i_src < 0) ? 0x8000 : 0;
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/* clear sign bit of integer */
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/* move to mantissa field */
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buf.m1 = (i_src < 0) ? -i_src : i_src;
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/* adjust mantissa field */
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if (ss != sizeof(long))
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buf.m1 <<= 16;
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nrm_ext(&buf);
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#ifdef PRT_STDERR
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fprintf(stderr,"CIF() buf.exp after nrm_ext() == %d\n\n",buf.exp);
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#endif
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compact(&buf,result,8);
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return(*result);
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}
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