1 /* Private floating point rounding and exceptions handling. 390/s390x version.
2 Copyright (C) 2019-2023 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
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.
9
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.
14
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 <https://www.gnu.org/licenses/>. */
18
19 #ifndef S390_FENV_PRIVATE_H
20 #define S390_FENV_PRIVATE_H 1
21
22 #include <fenv.h>
23 #include <fenv_libc.h>
24 #include <fpu_control.h>
25
26 static __always_inline void
27 libc_feholdexcept_s390 (fenv_t *envp)
28 {
29 fpu_control_t fpc, fpc_new;
30
31 /* Store the environment. */
32 _FPU_GETCW (fpc);
33 envp->__fpc = fpc;
34
35 /* Clear the current exception flags and dxc field.
36 Hold from generating fpu exceptions temporarily. */
37 fpc_new = fpc & ~(FPC_FLAGS_MASK | FPC_DXC_MASK | FPC_EXCEPTION_MASK);
38
39 /* Only set new environment if it has changed. */
40 if (fpc_new != fpc)
41 _FPU_SETCW (fpc_new);
42 }
43
44 #define libc_feholdexcept libc_feholdexcept_s390
45 #define libc_feholdexceptf libc_feholdexcept_s390
46 #define libc_feholdexceptl libc_feholdexcept_s390
47
48 static __always_inline void
49 libc_fesetround_s390 (int round)
50 {
51 __asm__ __volatile__ ("srnm 0(%0)" : : "a" (round));
52 }
53
54 #define libc_fesetround libc_fesetround_s390
55 #define libc_fesetroundf libc_fesetround_s390
56 #define libc_fesetroundl libc_fesetround_s390
57
58 static __always_inline void
59 libc_feholdexcept_setround_s390 (fenv_t *envp, int r)
60 {
61 fpu_control_t fpc, fpc_new;
62
63 _FPU_GETCW (fpc);
64 envp->__fpc = fpc;
65
66 /* Clear the current exception flags and dxc field.
67 Hold from generating fpu exceptions temporarily.
68 Reset rounding mode bits. */
69 fpc_new = fpc & ~(FPC_FLAGS_MASK | FPC_DXC_MASK | FPC_EXCEPTION_MASK
70 | FPC_RM_MASK);
71
72 /* Set new rounding mode. */
73 fpc_new |= (r & FPC_RM_MASK);
74
75 /* Only set new environment if it has changed. */
76 if (fpc_new != fpc)
77 _FPU_SETCW (fpc_new);
78 }
79
80 #define libc_feholdexcept_setround libc_feholdexcept_setround_s390
81 #define libc_feholdexcept_setroundf libc_feholdexcept_setround_s390
82 #define libc_feholdexcept_setroundl libc_feholdexcept_setround_s390
83
84 static __always_inline int
85 libc_fetestexcept_s390 (int excepts)
86 {
87 int res;
88 fexcept_t fpc;
89
90 _FPU_GETCW (fpc);
91
92 /* Get current exceptions. */
93 res = (fpc >> FPC_FLAGS_SHIFT) & FE_ALL_EXCEPT;
94 if ((fpc & FPC_NOT_FPU_EXCEPTION) == 0)
95 /* Bits 6, 7 of dxc-byte are zero,
96 thus bits 0-5 of dxc-byte correspond to the flag-bits.
97 Evaluate flags and last dxc-exception-code. */
98 res |= (fpc >> FPC_DXC_SHIFT) & FE_ALL_EXCEPT;
99
100 return res & excepts;
101 }
102
103 #define libc_fetestexcept libc_fetestexcept_s390
104 #define libc_fetestexceptf libc_fetestexcept_s390
105 #define libc_fetestexceptl libc_fetestexcept_s390
106
107 static __always_inline void
108 libc_fesetenv_s390 (const fenv_t *envp)
109 {
110 _FPU_SETCW (envp->__fpc);
111 }
112
113 #define libc_fesetenv libc_fesetenv_s390
114 #define libc_fesetenvf libc_fesetenv_s390
115 #define libc_fesetenvl libc_fesetenv_s390
116
117 static __always_inline int
118 libc_feupdateenv_test_s390 (const fenv_t *envp, int ex)
119 {
120 /* Get the currently raised exceptions. */
121 int excepts;
122 fexcept_t fpc_old;
123
124 _FPU_GETCW (fpc_old);
125
126 /* Get current exceptions. */
127 excepts = (fpc_old >> FPC_FLAGS_SHIFT) & FE_ALL_EXCEPT;
128 if ((fpc_old & FPC_NOT_FPU_EXCEPTION) == 0)
129 /* Bits 6, 7 of dxc-byte are zero,
130 thus bits 0-5 of dxc-byte correspond to the flag-bits.
131 Evaluate flags and last dxc-exception-code. */
132 excepts |= (fpc_old >> FPC_DXC_SHIFT) & FE_ALL_EXCEPT;
133
134 /* Merge the currently raised exceptions with those in envp. */
135 fpu_control_t fpc_new = envp->__fpc;
136 fpc_new |= excepts << FPC_FLAGS_SHIFT;
137
138 /* Install the new fpc from envp. */
139 if (fpc_new != fpc_old)
140 _FPU_SETCW (fpc_new);
141
142 /* Raise the exceptions if enabled in new fpc. */
143 if (__glibc_unlikely ((fpc_new >> FPC_EXCEPTION_MASK_SHIFT) & excepts))
144 __feraiseexcept (excepts);
145
146 return excepts & ex;
147 }
148
149 #define libc_feupdateenv_test libc_feupdateenv_test_s390
150 #define libc_feupdateenv_testf libc_feupdateenv_test_s390
151 #define libc_feupdateenv_testl libc_feupdateenv_test_s390
152
153 static __always_inline void
154 libc_feupdateenv_s390 (const fenv_t *envp)
155 {
156 libc_feupdateenv_test_s390 (envp, 0);
157 }
158
159 #define libc_feupdateenv libc_feupdateenv_s390
160 #define libc_feupdateenvf libc_feupdateenv_s390
161 #define libc_feupdateenvl libc_feupdateenv_s390
162
163 static __always_inline fenv_t
164 libc_handle_user_fenv_s390 (const fenv_t *envp)
165 {
166 fenv_t env;
167 if (envp == FE_DFL_ENV)
168 {
169 env.__fpc = _FPU_DEFAULT;
170 }
171 else if (envp == FE_NOMASK_ENV)
172 {
173 env.__fpc = FPC_EXCEPTION_MASK;
174 }
175 else
176 env = (*envp);
177
178 return env;
179 }
180
181 /* We have support for rounding mode context. */
182 #define HAVE_RM_CTX 1
183
184 static __always_inline void
185 libc_feholdsetround_s390_ctx (struct rm_ctx *ctx, int r)
186 {
187 fpu_control_t fpc;
188 int round;
189
190 _FPU_GETCW (fpc);
191 ctx->env.__fpc = fpc;
192
193 /* Check whether rounding modes are different. */
194 round = fpc & FPC_RM_MASK;
195
196 /* Set the rounding mode if changed. */
197 if (__glibc_unlikely (round != r))
198 {
199 ctx->updated_status = true;
200 libc_fesetround_s390 (r);
201 }
202 else
203 ctx->updated_status = false;
204 }
205
206 #define libc_feholdsetround_ctx libc_feholdsetround_s390_ctx
207 #define libc_feholdsetroundf_ctx libc_feholdsetround_s390_ctx
208 #define libc_feholdsetroundl_ctx libc_feholdsetround_s390_ctx
209
210 static __always_inline void
211 libc_feresetround_s390_ctx (struct rm_ctx *ctx)
212 {
213 /* Restore the rounding mode if updated. */
214 if (__glibc_unlikely (ctx->updated_status))
215 {
216 fpu_control_t fpc;
217 _FPU_GETCW (fpc);
218 fpc = ctx->env.__fpc | (fpc & FPC_FLAGS_MASK);
219 _FPU_SETCW (fpc);
220 }
221 }
222
223 #define libc_feresetround_ctx libc_feresetround_s390_ctx
224 #define libc_feresetroundf_ctx libc_feresetround_s390_ctx
225 #define libc_feresetroundl_ctx libc_feresetround_s390_ctx
226
227 static __always_inline void
228 libc_feholdsetround_noex_s390_ctx (struct rm_ctx *ctx, int r)
229 {
230 libc_feholdexcept_setround_s390 (&ctx->env, r);
231 }
232
233 #define libc_feholdsetround_noex_ctx libc_feholdsetround_noex_s390_ctx
234 #define libc_feholdsetround_noexf_ctx libc_feholdsetround_noex_s390_ctx
235 #define libc_feholdsetround_noexl_ctx libc_feholdsetround_noex_s390_ctx
236
237 static __always_inline void
238 libc_feresetround_noex_s390_ctx (struct rm_ctx *ctx)
239 {
240 /* Restore exception flags and rounding mode. */
241 libc_fesetenv_s390 (&ctx->env);
242 }
243
244 #define libc_feresetround_noex_ctx libc_feresetround_noex_s390_ctx
245 #define libc_feresetround_noexf_ctx libc_feresetround_noex_s390_ctx
246 #define libc_feresetround_noexl_ctx libc_feresetround_noex_s390_ctx
247
248 #include_next <fenv_private.h>
249
250 #endif