1 // SPDX-License-Identifier: GPL-2.0-only 1 // SPDX-License-Identifier: GPL-2.0-only
2 /* IEEE754 floating point arithmetic 2 /* IEEE754 floating point arithmetic
3 * single precision 3 * single precision
4 */ 4 */
5 /* 5 /*
6 * MIPS floating point support 6 * MIPS floating point support
7 * Copyright (C) 1994-2000 Algorithmics Ltd. 7 * Copyright (C) 1994-2000 Algorithmics Ltd.
8 */ 8 */
9 9
10 #include "ieee754sp.h" 10 #include "ieee754sp.h"
11 #include "ieee754dp.h" 11 #include "ieee754dp.h"
12 12
13 static inline union ieee754sp ieee754sp_nan_fd 13 static inline union ieee754sp ieee754sp_nan_fdp(int xs, u64 xm)
14 { 14 {
15 return buildsp(xs, SP_EMAX + 1 + SP_EB 15 return buildsp(xs, SP_EMAX + 1 + SP_EBIAS,
16 xm >> (DP_FBITS - SP_FB 16 xm >> (DP_FBITS - SP_FBITS));
17 } 17 }
18 18
19 union ieee754sp ieee754sp_fdp(union ieee754dp 19 union ieee754sp ieee754sp_fdp(union ieee754dp x)
20 { 20 {
21 union ieee754sp y; 21 union ieee754sp y;
22 u32 rm; 22 u32 rm;
23 23
24 COMPXDP; 24 COMPXDP;
25 COMPYSP; 25 COMPYSP;
26 26
27 EXPLODEXDP; 27 EXPLODEXDP;
28 28
29 ieee754_clearcx(); 29 ieee754_clearcx();
30 30
31 FLUSHXDP; 31 FLUSHXDP;
32 32
33 switch (xc) { 33 switch (xc) {
34 case IEEE754_CLASS_SNAN: 34 case IEEE754_CLASS_SNAN:
35 x = ieee754dp_nanxcpt(x); 35 x = ieee754dp_nanxcpt(x);
36 EXPLODEXDP; 36 EXPLODEXDP;
37 fallthrough; 37 fallthrough;
38 case IEEE754_CLASS_QNAN: 38 case IEEE754_CLASS_QNAN:
39 y = ieee754sp_nan_fdp(xs, xm); 39 y = ieee754sp_nan_fdp(xs, xm);
40 if (!ieee754_csr.nan2008) { 40 if (!ieee754_csr.nan2008) {
41 EXPLODEYSP; 41 EXPLODEYSP;
42 if (!ieee754_class_nan 42 if (!ieee754_class_nan(yc))
43 y = ieee754sp_ 43 y = ieee754sp_indef();
44 } 44 }
45 return y; 45 return y;
46 46
47 case IEEE754_CLASS_INF: 47 case IEEE754_CLASS_INF:
48 return ieee754sp_inf(xs); 48 return ieee754sp_inf(xs);
49 49
50 case IEEE754_CLASS_ZERO: 50 case IEEE754_CLASS_ZERO:
51 return ieee754sp_zero(xs); 51 return ieee754sp_zero(xs);
52 52
53 case IEEE754_CLASS_DNORM: 53 case IEEE754_CLASS_DNORM:
54 /* can't possibly be sp repres 54 /* can't possibly be sp representable */
55 ieee754_setcx(IEEE754_UNDERFLO 55 ieee754_setcx(IEEE754_UNDERFLOW);
56 ieee754_setcx(IEEE754_INEXACT) 56 ieee754_setcx(IEEE754_INEXACT);
57 if ((ieee754_csr.rm == FPU_CSR 57 if ((ieee754_csr.rm == FPU_CSR_RU && !xs) ||
58 (ieee754_csr.r 58 (ieee754_csr.rm == FPU_CSR_RD && xs))
59 return ieee754sp_mind( 59 return ieee754sp_mind(xs);
60 return ieee754sp_zero(xs); 60 return ieee754sp_zero(xs);
61 61
62 case IEEE754_CLASS_NORM: 62 case IEEE754_CLASS_NORM:
63 break; 63 break;
64 } 64 }
65 65
66 /* 66 /*
67 * Convert from DP_FBITS to SP_FBITS+3 67 * Convert from DP_FBITS to SP_FBITS+3 with sticky right shift.
68 */ 68 */
69 rm = (xm >> (DP_FBITS - (SP_FBITS + 3) 69 rm = (xm >> (DP_FBITS - (SP_FBITS + 3))) |
70 ((xm << (64 - (DP_FBITS - (SP_FBI 70 ((xm << (64 - (DP_FBITS - (SP_FBITS + 3)))) != 0);
71 71
72 return ieee754sp_format(xs, xe, rm); 72 return ieee754sp_format(xs, xe, rm);
73 } 73 }
74 74
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