ack/mach/proto/fp/fif4.c
1989-07-25 14:21:09 +00:00

50 lines
911 B
C

/*
(c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
See the copyright notice in the ACK home directory, in the file "Copyright".
*/
/* $Header$ */
/*
MULTIPLY AND DISMEMBER PARTS (FIF 4)
*/
#include "FP_types.h"
#include "FP_shift.h"
_float sbf4();
struct fif4_returns {
_float ipart;
_float fpart;
};
fif4(p,x,y)
_float x,y;
struct fif4_returns *p;
{
EXTEND e1,e2;
extend((_double *)&y,&e1,sizeof(_float));
extend((_double *)&x,&e2,sizeof(_float));
/* do a multiply */
mul_ext(&e1,&e2);
e2 = e1;
compact(&e2, (_double *)&y, sizeof(_float));
if (e1.exp < 0) {
p->ipart = 0;
p->fpart = y;
return;
}
if (e1.exp > 30 - SGL_M1LEFT) {
p->ipart = y;
p->fpart = 0;
return;
}
b64_sft(&e1.m1, 64 - e1.exp);
b64_sft(&e1.m1, e1.exp - 64); /* "loose" low order bits */
compact(&e1,(_double *) &(p->ipart), sizeof(SINGLE));
p->fpart = sbf4(p->ipart, y);
}