ack/mach/proto/fp/cfi.c
1988-04-07 11:40:46 +00:00

54 lines
1.2 KiB
C

/*
(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 FLOAT TO UNSIGNED
N.B. The caller must know what it is getting.
A LONG is always returned. If it is an
integer the high byte is cleared first.
*/
#include "FP_trap.h"
#include "FP_types.h"
long
cfi(ds,ss,src)
int ds; /* destination size (2 or 4) */
int ss; /* source size (4 or 8) */
_double src; /* assume worst case */
{
EXTEND buf;
long new;
short newint, max_exp;
extend(&src,&buf,ss); /* get extended format */
#ifdef PRT_EXT
prt_ext("CFI() entry:",&buf);
#endif PRT_EXT
buf.exp--; /* additional bias correction */
if (buf.exp < 1) { /* no conversion needed */
src.__double[ss == 8] = 0L;
return(0L);
}
max_exp = (ds << 3) - 1; /* signed numbers */
/* have more limited max_exp */
if (buf.exp > max_exp) {
#ifdef PRT_EXT
prt_ext("CFI() INT OVERFLOW", &buf);
#endif PRT_EXT
trap(EIOVFL); /* integer overflow */
buf.exp %= max_exp; /* truncate */
}
new = buf.m1 >> (32-buf.exp);
if (buf.sign)
new = -new;
done:
src.__double[ss == 8] = new;
return(new);
}