57 lines
1.2 KiB
C
57 lines
1.2 KiB
C
|
/*
|
||
|
|
CONVERT INTEGER TO FLOAT
|
||
|
|
|
||
|
|
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"
|
||
|
|
|
||
|
|
_float
|
||
|
|
cif4(ss,src)
|
||
|
|
int ss; /* source size */
|
||
|
|
long src; /* largest possible integer to convert */
|
||
|
|
{
|
||
|
|
EXTEND buf;
|
||
|
|
short *ipt;
|
||
|
|
long i_src;
|
||
|
|
_float *result;
|
||
|
|
|
||
|
|
zrf_ext(&buf);
|
||
|
|
if (ss == sizeof(long)) {
|
||
|
|
buf.exp = 33;
|
||
|
|
i_src = src;
|
||
|
|
result = (_float *) &src;
|
||
|
|
}
|
||
|
|
else {
|
||
|
|
ipt = (short *) &src;
|
||
|
|
i_src = (long) *ipt;
|
||
|
|
buf.exp = 17;
|
||
|
|
result = (_float *) &ss;
|
||
|
|
}
|
||
|
|
#ifdef PRT_STDERR
|
||
|
|
fprintf(stderr,"CIF4(ds(%d),ss(%d),src(%D))\n\n",4,ss,i_src);
|
||
|
|
#endif
|
||
|
|
if (i_src == 0) {
|
||
|
|
*result = (_float) 0L;
|
||
|
|
return(0L);
|
||
|
|
}
|
||
|
|
/* 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); /* adjust mantissa field */
|
||
|
|
#ifdef PRT_STDERR
|
||
|
|
fprintf(stderr,"CIF() buf.exp after nrm_ext() == %d\n\n",buf.exp);
|
||
|
|
#endif
|
||
|
|
compact(&buf,(_double *) result,4); /* put on stack */
|
||
|
|
return(*result);
|
||
|
|
}
|