ack/mach/proto/fp/fif8.c

52 lines
954 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 8)
*/
#include "FP_types.h"
#include "FP_shift.h"
_double sbf8();
struct fif8_returns {
_double ipart;
_double fpart;
};
fif8(p,x,y)
_double x,y;
struct fif8_returns *p;
{
EXTEND e1,e2;
extend(&y,&e1,sizeof(_double));
extend(&x,&e2,sizeof(_double));
/* do a multiply */
mul_ext(&e1,&e2);
e2 = e1;
compact(&e2, &y, sizeof(_double));
if (e1.exp < 0) {
p->ipart.__double[0] = 0;
p->ipart.__double[1] = 0;
p->fpart = y;
return;
}
if (e1.exp > 62 - DBL_M1LEFT) {
p->ipart = y;
p->fpart.__double[0] = 0;
p->fpart.__double[1] = 0;
return;
}
b64_sft(&e1.m1, 63 - e1.exp);
b64_sft(&e1.m1, e1.exp - 63); /* "loose" low order bits */
compact(&e1, &(p->ipart), sizeof(DOUBLE));
p->fpart = sbf8(p->ipart, y);
}