1 /* Internal libc stuff for floating point environment routines.
2 Copyright (C) 1997-2019 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
20 #define _FENV_LIBC_H 1
26 extern const fenv_t
*__fe_nomask_env_priv (void);
28 extern const fenv_t
*__fe_mask_env (void) attribute_hidden
;
30 /* The sticky bits in the FPSCR indicating exceptions have occurred. */
31 #define FPSCR_STICKY_BITS ((FE_ALL_EXCEPT | FE_ALL_INVALID) & ~FE_INVALID)
33 /* Equivalent to fegetenv, but returns a fenv_t instead of taking a
35 #define fegetenv_register() __builtin_mffs()
37 /* Equivalent to fesetenv, but takes a fenv_t instead of a pointer. */
38 #define fesetenv_register(env) \
41 if(GLRO(dl_hwcap) & PPC_FEATURE_HAS_DFP) \
42 asm volatile (".machine push; " \
43 ".machine \"power6\"; " \
44 "mtfsf 0xff,%0,1,0; " \
45 ".machine pop" : : "f" (d)); \
47 __builtin_mtfsf (0xff, d); \
50 /* This very handy macro:
51 - Sets the rounding mode to 'round to nearest';
52 - Sets the processor into IEEE mode; and
53 - Prevents exceptions from being raised for inexact results.
54 These things happen to be exactly what you need for typical elementary
56 #define relax_fenv_state() \
58 if (GLRO(dl_hwcap) & PPC_FEATURE_HAS_DFP) \
59 asm (".machine push; .machine \"power6\"; " \
60 "mtfsfi 7,0,1; .machine pop"); \
64 /* Set/clear a particular FPSCR bit (for instance,
65 reset_fpscr_bit(FPSCR_VE);
66 prevents INVALID exceptions from being raised). */
67 #define set_fpscr_bit(x) asm volatile ("mtfsb1 %0" : : "i"(x))
68 #define reset_fpscr_bit(x) asm volatile ("mtfsb0 %0" : : "i"(x))
78 __fesetround_inline (int round
)
80 if ((unsigned int) round
< 2)
82 asm volatile ("mtfsb0 30");
83 if ((unsigned int) round
== 0)
84 asm volatile ("mtfsb0 31");
86 asm volatile ("mtfsb1 31");
90 asm volatile ("mtfsb1 30");
91 if ((unsigned int) round
== 2)
92 asm volatile ("mtfsb0 31");
94 asm volatile ("mtfsb1 31");
100 /* Definitions of all the FPSCR bit numbers */
102 FPSCR_FX
= 0, /* exception summary */
103 FPSCR_FEX
, /* enabled exception summary */
104 FPSCR_VX
, /* invalid operation summary */
105 FPSCR_OX
, /* overflow */
106 FPSCR_UX
, /* underflow */
107 FPSCR_ZX
, /* zero divide */
108 FPSCR_XX
, /* inexact */
109 FPSCR_VXSNAN
, /* invalid operation for sNaN */
110 FPSCR_VXISI
, /* invalid operation for Inf-Inf */
111 FPSCR_VXIDI
, /* invalid operation for Inf/Inf */
112 FPSCR_VXZDZ
, /* invalid operation for 0/0 */
113 FPSCR_VXIMZ
, /* invalid operation for Inf*0 */
114 FPSCR_VXVC
, /* invalid operation for invalid compare */
115 FPSCR_FR
, /* fraction rounded [fraction was incremented by round] */
116 FPSCR_FI
, /* fraction inexact */
117 FPSCR_FPRF_C
, /* result class descriptor */
118 FPSCR_FPRF_FL
, /* result less than (usually, less than 0) */
119 FPSCR_FPRF_FG
, /* result greater than */
120 FPSCR_FPRF_FE
, /* result equal to */
121 FPSCR_FPRF_FU
, /* result unordered */
122 FPSCR_20
, /* reserved */
123 FPSCR_VXSOFT
, /* invalid operation set by software */
124 FPSCR_VXSQRT
, /* invalid operation for square root */
125 FPSCR_VXCVI
, /* invalid operation for invalid integer convert */
126 FPSCR_VE
, /* invalid operation exception enable */
127 FPSCR_OE
, /* overflow exception enable */
128 FPSCR_UE
, /* underflow exception enable */
129 FPSCR_ZE
, /* zero divide exception enable */
130 FPSCR_XE
, /* inexact exception enable */
132 FPSCR_29
, /* Reserved in ISA 2.05 */
134 FPSCR_NI
/* non-IEEE mode (typically, no denormalised numbers) */
135 #endif /* _ARCH_PWR6 */
136 /* the remaining two least-significant bits keep the rounding mode */
140 fenv_reg_to_exceptions (unsigned long long l
)
143 if (l
& (1 << (31 - FPSCR_XE
)))
144 result
|= FE_INEXACT
;
145 if (l
& (1 << (31 - FPSCR_ZE
)))
146 result
|= FE_DIVBYZERO
;
147 if (l
& (1 << (31 - FPSCR_UE
)))
148 result
|= FE_UNDERFLOW
;
149 if (l
& (1 << (31 - FPSCR_OE
)))
150 result
|= FE_OVERFLOW
;
151 if (l
& (1 << (31 - FPSCR_VE
)))
152 result
|= FE_INVALID
;
157 /* Not supported in ISA 2.05. Provided for source compat only. */
159 #endif /* _ARCH_PWR6 */
161 /* This operation (i) sets the appropriate FPSCR bits for its
162 parameter, (ii) converts sNaN to the corresponding qNaN, and (iii)
163 otherwise passes its parameter through unchanged (in particular, -0
164 and +0 stay as they were). The `obvious' way to do this is optimised
167 ({ double d; asm volatile ("fmul %0,%1,%2" \
169 : "f" (x), "f"((float)1.0)); d; })
171 ({ float f; asm volatile ("fmuls %0,%1,%2" \
173 : "f" (x), "f"((float)1.0)); f; })
175 #endif /* fenv_libc.h */