57 lines
1.3 KiB
C
57 lines
1.3 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".
|
|
*/
|
|
|
|
/* $Id$ */
|
|
|
|
/*
|
|
ADD TWO EXTENDED FORMAT NUMBERS
|
|
*/
|
|
|
|
#include "FP_types.h"
|
|
|
|
void
|
|
add_ext(e1,e2)
|
|
register EXTEND *e1,*e2;
|
|
{
|
|
if ((e2->m1 | e2->m2) == 0L) {
|
|
return;
|
|
}
|
|
if ((e1->m1 | e1->m2) == 0L) {
|
|
*e1 = *e2;
|
|
return;
|
|
}
|
|
sft_ext(e1, e2); /* adjust mantissas to equal powers */
|
|
if (e1->sign != e2->sign) {
|
|
/* e1 + e2 = e1 - (-e2) */
|
|
if (e2->m1 > e1->m1 ||
|
|
(e2->m1 == e1->m1 && e2->m2 > e1->m2)) {
|
|
/* abs(e2) > abs(e1) */
|
|
EXTEND x;
|
|
|
|
x = *e1;
|
|
*e1 = *e2;
|
|
if (x.m2 > e1->m2) {
|
|
e1->m1 -= 1; /* carry in */
|
|
}
|
|
e1->m1 -= x.m1;
|
|
e1->m2 -= x.m2;
|
|
}
|
|
else {
|
|
if (e2->m2 > e1->m2)
|
|
e1->m1 -= 1; /* carry in */
|
|
e1->m1 -= e2->m1;
|
|
e1->m2 -= e2->m2;
|
|
}
|
|
}
|
|
else {
|
|
if (b64_add(&e1->mantissa,&e2->mantissa)) { /* addition carry */
|
|
b64_rsft(&e1->mantissa); /* shift mantissa one bit RIGHT */
|
|
e1->m1 |= 0x80000000L; /* set max bit */
|
|
e1->exp++; /* increase the exponent */
|
|
}
|
|
}
|
|
nrm_ext(e1);
|
|
}
|