minix/lib/ack/float/cif8.fc
2009-11-09 10:26:00 +00:00

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1.1 KiB
Text

/*
(c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
/*
CONVERT INTEGER TO FLOAT (CIF n 8)
THIS ROUTINE WORKS BY FILLING AN EXTENDED
WITH THE INTEGER VALUE IN EXTENDED FORMAT
AND USES COMPACT() TO PUT IT INTO THE PROPER
FLOATING POINT PRECISION.
*/
#include "FP_types.h"
void
cif8(ss,src)
int ss; /* source size */
long src; /* largest possible integer to convert */
{
EXTEND buf;
DOUBLE *result; /* for return value */
short *ipt;
long i_src;
result = (DOUBLE *) ((void *) &ss); /* always */
zrf_ext(&buf);
if (ss == sizeof(long)) {
buf.exp = 31;
i_src = src;
}
else {
ipt = (short *) &src;
i_src = (long) *ipt;
buf.exp = 15;
}
if (i_src == 0) {
zrf8(result);
return;
}
/* ESTABLISHED THAT src != 0 */
/* adjust exponent field */
buf.sign = (i_src < 0) ? 0x8000 : 0;
/* clear sign bit of integer */
/* move to mantissa field */
buf.m1 = (i_src < 0) ? -i_src : i_src;
/* adjust mantissa field */
if (ss != sizeof(long))
buf.m1 <<= 16;
nrm_ext(&buf);
compact(&buf,&result->d[0],8);
}