xref: /openbmc/linux/arch/mips/math-emu/sp_fint.c (revision fb574682)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* IEEE754 floating point arithmetic
3  * single precision
4  */
5 /*
6  * MIPS floating point support
7  * Copyright (C) 1994-2000 Algorithmics Ltd.
8  */
9 
10 #include "ieee754sp.h"
11 
12 union ieee754sp ieee754sp_fint(int x)
13 {
14 	unsigned int xm;
15 	int xe;
16 	int xs;
17 
18 	ieee754_clearcx();
19 
20 	if (x == 0)
21 		return ieee754sp_zero(0);
22 	if (x == 1 || x == -1)
23 		return ieee754sp_one(x < 0);
24 	if (x == 10 || x == -10)
25 		return ieee754sp_ten(x < 0);
26 
27 	xs = (x < 0);
28 	if (xs) {
29 		if (x == (1 << 31))
30 			xm = ((unsigned) 1 << 31);	/* max neg can't be safely negated */
31 		else
32 			xm = -x;
33 	} else {
34 		xm = x;
35 	}
36 	xe = SP_FBITS + 3;
37 
38 	if (xm >> (SP_FBITS + 1 + 3)) {
39 		/* shunt out overflow bits
40 		 */
41 		while (xm >> (SP_FBITS + 1 + 3)) {
42 			SPXSRSX1();
43 		}
44 	} else {
45 		/* normalize in grs extended single precision
46 		 */
47 		while ((xm >> (SP_FBITS + 3)) == 0) {
48 			xm <<= 1;
49 			xe--;
50 		}
51 	}
52 	return ieee754sp_format(xs, xe, xm);
53 }
54