xref: /OK3568_Linux_fs/kernel/arch/mips/math-emu/sp_fint.c (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /* IEEE754 floating point arithmetic
3*4882a593Smuzhiyun  * single precision
4*4882a593Smuzhiyun  */
5*4882a593Smuzhiyun /*
6*4882a593Smuzhiyun  * MIPS floating point support
7*4882a593Smuzhiyun  * Copyright (C) 1994-2000 Algorithmics Ltd.
8*4882a593Smuzhiyun  */
9*4882a593Smuzhiyun 
10*4882a593Smuzhiyun #include "ieee754sp.h"
11*4882a593Smuzhiyun 
ieee754sp_fint(int x)12*4882a593Smuzhiyun union ieee754sp ieee754sp_fint(int x)
13*4882a593Smuzhiyun {
14*4882a593Smuzhiyun 	unsigned int xm;
15*4882a593Smuzhiyun 	int xe;
16*4882a593Smuzhiyun 	int xs;
17*4882a593Smuzhiyun 
18*4882a593Smuzhiyun 	ieee754_clearcx();
19*4882a593Smuzhiyun 
20*4882a593Smuzhiyun 	if (x == 0)
21*4882a593Smuzhiyun 		return ieee754sp_zero(0);
22*4882a593Smuzhiyun 	if (x == 1 || x == -1)
23*4882a593Smuzhiyun 		return ieee754sp_one(x < 0);
24*4882a593Smuzhiyun 	if (x == 10 || x == -10)
25*4882a593Smuzhiyun 		return ieee754sp_ten(x < 0);
26*4882a593Smuzhiyun 
27*4882a593Smuzhiyun 	xs = (x < 0);
28*4882a593Smuzhiyun 	if (xs) {
29*4882a593Smuzhiyun 		if (x == (1 << 31))
30*4882a593Smuzhiyun 			xm = ((unsigned) 1 << 31);	/* max neg can't be safely negated */
31*4882a593Smuzhiyun 		else
32*4882a593Smuzhiyun 			xm = -x;
33*4882a593Smuzhiyun 	} else {
34*4882a593Smuzhiyun 		xm = x;
35*4882a593Smuzhiyun 	}
36*4882a593Smuzhiyun 	xe = SP_FBITS + 3;
37*4882a593Smuzhiyun 
38*4882a593Smuzhiyun 	if (xm >> (SP_FBITS + 1 + 3)) {
39*4882a593Smuzhiyun 		/* shunt out overflow bits
40*4882a593Smuzhiyun 		 */
41*4882a593Smuzhiyun 		while (xm >> (SP_FBITS + 1 + 3)) {
42*4882a593Smuzhiyun 			SPXSRSX1();
43*4882a593Smuzhiyun 		}
44*4882a593Smuzhiyun 	} else {
45*4882a593Smuzhiyun 		/* normalize in grs extended single precision
46*4882a593Smuzhiyun 		 */
47*4882a593Smuzhiyun 		while ((xm >> (SP_FBITS + 3)) == 0) {
48*4882a593Smuzhiyun 			xm <<= 1;
49*4882a593Smuzhiyun 			xe--;
50*4882a593Smuzhiyun 		}
51*4882a593Smuzhiyun 	}
52*4882a593Smuzhiyun 	return ieee754sp_format(xs, xe, xm);
53*4882a593Smuzhiyun }
54