xref: /openbmc/linux/arch/mips/math-emu/ieee754sp.h (revision 842ed298)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * IEEE754 floating point
4  * double precision internal header file
5  */
6 /*
7  * MIPS floating point support
8  * Copyright (C) 1994-2000 Algorithmics Ltd.
9  */
10 
11 #include <linux/compiler.h>
12 
13 #include "ieee754int.h"
14 
15 #define assert(expr) ((void)0)
16 
17 #define SP_EBIAS	127
18 #define SP_EMIN		(-126)
19 #define SP_EMAX		127
20 #define SP_FBITS	23
21 #define SP_MBITS	23
22 
23 #define SP_MBIT(x)	((u32)1 << (x))
24 #define SP_HIDDEN_BIT	SP_MBIT(SP_FBITS)
25 #define SP_SIGN_BIT	SP_MBIT(31)
26 
27 #define SPSIGN(sp)	(sp.sign)
28 #define SPBEXP(sp)	(sp.bexp)
29 #define SPMANT(sp)	(sp.mant)
30 
31 static inline int ieee754sp_finite(union ieee754sp x)
32 {
33 	return SPBEXP(x) != SP_EMAX + 1 + SP_EBIAS;
34 }
35 
36 /* 64 bit right shift with rounding */
37 #define XSPSRS64(v, rs)						\
38 	(((rs) >= 64) ? ((v) != 0) : ((v) >> (rs)) | ((v) << (64-(rs)) != 0))
39 
40 /* 3bit extended single precision sticky right shift */
41 #define XSPSRS(v, rs)						\
42 	((rs > (SP_FBITS+3))?1:((v) >> (rs)) | ((v) << (32-(rs)) != 0))
43 
44 #define XSPSRS1(m) \
45 	((m >> 1) | (m & 1))
46 
47 #define SPXSRSX1() \
48 	(xe++, (xm = XSPSRS1(xm)))
49 
50 #define SPXSRSY1() \
51 	(ye++, (ym = XSPSRS1(ym)))
52 
53 /* convert denormal to normalized with extended exponent */
54 #define SPDNORMx(m,e) \
55 	while ((m >> SP_FBITS) == 0) { m <<= 1; e--; }
56 #define SPDNORMX	SPDNORMx(xm, xe)
57 #define SPDNORMY	SPDNORMx(ym, ye)
58 #define SPDNORMZ	SPDNORMx(zm, ze)
59 
60 static inline union ieee754sp buildsp(int s, int bx, unsigned int m)
61 {
62 	union ieee754sp r;
63 
64 	assert((s) == 0 || (s) == 1);
65 	assert((bx) >= SP_EMIN - 1 + SP_EBIAS
66 	       && (bx) <= SP_EMAX + 1 + SP_EBIAS);
67 	assert(((m) >> SP_FBITS) == 0);
68 
69 	r.sign = s;
70 	r.bexp = bx;
71 	r.mant = m;
72 
73 	return r;
74 }
75 
76 extern union ieee754sp __cold ieee754sp_nanxcpt(union ieee754sp);
77 extern union ieee754sp ieee754sp_format(int, int, unsigned);
78