xref: /linux/arch/mips/math-emu/ieee754dp.h (revision b8d312aa075f33282565467662c4628dae0a2aff)
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 DP_EBIAS	1023
18 #define DP_EMIN		(-1022)
19 #define DP_EMAX		1023
20 #define DP_FBITS	52
21 #define DP_MBITS	52
22 
23 #define DP_MBIT(x)	((u64)1 << (x))
24 #define DP_HIDDEN_BIT	DP_MBIT(DP_FBITS)
25 #define DP_SIGN_BIT	DP_MBIT(63)
26 
27 #define DPSIGN(dp)	(dp.sign)
28 #define DPBEXP(dp)	(dp.bexp)
29 #define DPMANT(dp)	(dp.mant)
30 
31 static inline int ieee754dp_finite(union ieee754dp x)
32 {
33 	return DPBEXP(x) != DP_EMAX + 1 + DP_EBIAS;
34 }
35 
36 /* 3bit extended double precision sticky right shift */
37 #define XDPSRS(v,rs)	\
38 	((rs > (DP_FBITS+3))?1:((v) >> (rs)) | ((v) << (64-(rs)) != 0))
39 
40 #define XDPSRSX1() \
41 	(xe++, (xm = (xm >> 1) | (xm & 1)))
42 
43 #define XDPSRS1(v)	\
44 	(((v) >> 1) | ((v) & 1))
45 
46 /* 32bit * 32bit => 64bit unsigned integer multiplication */
47 #define DPXMULT(x, y)	((u64)(x) * (u64)y)
48 
49 /* convert denormal to normalized with extended exponent */
50 #define DPDNORMx(m,e) \
51 	while ((m >> DP_FBITS) == 0) { m <<= 1; e--; }
52 #define DPDNORMX	DPDNORMx(xm, xe)
53 #define DPDNORMY	DPDNORMx(ym, ye)
54 #define DPDNORMZ	DPDNORMx(zm, ze)
55 
56 static inline union ieee754dp builddp(int s, int bx, u64 m)
57 {
58 	union ieee754dp r;
59 
60 	assert((s) == 0 || (s) == 1);
61 	assert((bx) >= DP_EMIN - 1 + DP_EBIAS
62 	       && (bx) <= DP_EMAX + 1 + DP_EBIAS);
63 	assert(((m) >> DP_FBITS) == 0);
64 
65 	r.sign = s;
66 	r.bexp = bx;
67 	r.mant = m;
68 
69 	return r;
70 }
71 
72 extern union ieee754dp __cold ieee754dp_nanxcpt(union ieee754dp);
73 extern union ieee754dp ieee754dp_format(int, int, u64);
74