1 /* Software floating-point emulation.
2 Definitions for IEEE Quad Precision on the PowerPC.
3 Copyright (C) 2016-2023 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5 Contributed by Michael Meissner (meissner@linux.vnet.ibm.com).
6
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
11
12 In addition to the permissions in the GNU Lesser General Public
13 License, the Free Software Foundation gives you unlimited
14 permission to link the compiled version of this file into
15 combinations with other programs, and to distribute those
16 combinations without any restriction coming from the use of this
17 file. (The Lesser General Public License restrictions do apply in
18 other respects; for example, they cover modification of the file,
19 and distribution when not linked into a combine executable.)
20
21 The GNU C Library is distributed in the hope that it will be useful,
22 but WITHOUT ANY WARRANTY; without even the implied warranty of
23 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
24 Lesser General Public License for more details.
25
26 You should have received a copy of the GNU Lesser General Public
27 License along with the GNU C Library; if not, see
28 <http://www.gnu.org/licenses/>. */
29
30 /* Override the types for IEEE 128-bit scalar and complex. We need to use the
31 same IEEE 128-bit type (either long double or _Float128) for both the
32 128-bit scalar type and for the base type in _Complex. Otherwise, if
33 different types are used, there may be problems in mixing _Complex values
34 with the scalar value.
35
36 We can't use _Compelx _float128 since GCC doesn't allow it. It only allows
37 _Complex for _Float128 or for long double.
38
39 We use _Float128 when long double is IBM double-double or 64-bit, and long
40 double when long double uses the IEEE 128-bit type. We need to do this
41 because the compiler has a built-in prototype for __mulkc3 and __divkc3
42 using those types. Since we are declaring these functions here, we need to
43 use the same type that the compiler uses (i.e. we can't just always use
44 _Float128).
45
46 Even though the type _Float128 and long double (when long double uses IEEE
47 128-bits) both hold IEEE 128-bit values, the front ends treat these as two
48 separate types.
49
50 The extension keyword __float128 is currently problematical because it can
51 either be a synonym for _Float128 (when long double is IBM) or for long
52 double (when long double is IEEE). */
53
54 #ifdef __LONG_DOUBLE_IEEE128__
55 #define TFtype long double
56 #define TCtype _Complex long double
57
58 #else
59 #define TFtype _Float128
60 #define TCtype _Complex _Float128
61 #endif
62
63 /* Force the use of the VSX instruction set. */
64 #if defined(_ARCH_PPC) && (!defined(__VSX__) || !defined(__FLOAT128__))
65 #pragma GCC target ("vsx,float128")
66 #endif
67
68 #include <stddef.h>
69 #include <quad.h>
70
71 #define IBM128_TYPE __ibm128
72
73 /* Add prototypes of the library functions created. In case the appropriate
74 int/long types are not declared in scope by the time quad.h is included,
75 provide our own version. */
76 typedef int SItype_ppc __attribute__ ((__mode__ (__SI__)));
77 typedef int DItype_ppc __attribute__ ((__mode__ (__DI__)));
78 typedef unsigned USItype_ppc __attribute__ ((__mode__ (__SI__)));
79 typedef unsigned UDItype_ppc __attribute__ ((__mode__ (__DI__)));
80
81 #ifdef _ARCH_PPC64
82 typedef int TItype_ppc __attribute__ ((__mode__ (__TI__)));
83 typedef unsigned UTItype_ppc __attribute__ ((__mode__ (__TI__)));
84 #endif
85
86 /* Software emulation functions. */
87 extern TFtype __addkf3_sw (TFtype, TFtype);
88 extern TFtype __subkf3_sw (TFtype, TFtype);
89 extern TFtype __mulkf3_sw (TFtype, TFtype);
90 extern TFtype __divkf3_sw (TFtype, TFtype);
91 extern TFtype __negkf2_sw (TFtype);
92 extern TFtype __powikf2_sw (TFtype, SItype_ppc);
93 extern CMPtype __eqkf2_sw (TFtype, TFtype);
94 extern CMPtype __gekf2_sw (TFtype, TFtype);
95 extern CMPtype __lekf2_sw (TFtype, TFtype);
96 extern CMPtype __unordkf2_sw (TFtype, TFtype);
97 extern TFtype __extendsfkf2_sw (float);
98 extern TFtype __extenddfkf2_sw (double);
99 extern float __trunckfsf2_sw (TFtype);
100 extern double __trunckfdf2_sw (TFtype);
101 extern SItype_ppc __fixkfsi_sw (TFtype);
102 extern DItype_ppc __fixkfdi_sw (TFtype);
103 extern USItype_ppc __fixunskfsi_sw (TFtype);
104 extern UDItype_ppc __fixunskfdi_sw (TFtype);
105 extern TFtype __floatsikf_sw (SItype_ppc);
106 extern TFtype __floatdikf_sw (DItype_ppc);
107 #ifdef _ARCH_PPC64
108 extern TFtype __floattikf_sw (TItype_ppc);
109 #endif
110 extern TFtype __floatunsikf_sw (USItype_ppc);
111 extern TFtype __floatundikf_sw (UDItype_ppc);
112 #ifdef _ARCH_PPC64
113 extern TFtype __floatuntikf_sw (UTItype_ppc);
114 extern TItype_ppc __fixkfti_sw (TFtype);
115 extern UTItype_ppc __fixunskfti_sw (TFtype);
116 #endif
117 extern IBM128_TYPE __extendkftf2_sw (TFtype);
118 extern TFtype __trunctfkf2_sw (IBM128_TYPE);
119 extern TCtype __mulkc3_sw (TFtype, TFtype, TFtype, TFtype);
120 extern TCtype __divkc3_sw (TFtype, TFtype, TFtype, TFtype);
121
122 #ifdef _ARCH_PPC64
123 extern TItype_ppc __fixkfti (TFtype);
124 extern UTItype_ppc __fixunskfti (TFtype);
125 extern TFtype __floattikf (TItype_ppc);
126 extern TFtype __floatuntikf (UTItype_ppc);
127 #endif
128
129 /* Functions using the ISA 3.0 hardware support. If the code is compiled with
130 -mcpu=power9, it will not use these functions, but if it was compiled with
131 -mcpu=power7 or -mcpu=power8 and run on a ISA 3.0 system, it will use the
132 hardware instruction. */
133 extern TFtype __addkf3_hw (TFtype, TFtype);
134 extern TFtype __subkf3_hw (TFtype, TFtype);
135 extern TFtype __mulkf3_hw (TFtype, TFtype);
136 extern TFtype __divkf3_hw (TFtype, TFtype);
137 extern TFtype __negkf2_hw (TFtype);
138 extern TFtype __powikf2_hw (TFtype, SItype_ppc);
139 extern CMPtype __eqkf2_hw (TFtype, TFtype);
140 extern CMPtype __gekf2_hw (TFtype, TFtype);
141 extern CMPtype __lekf2_hw (TFtype, TFtype);
142 extern CMPtype __unordkf2_hw (TFtype, TFtype);
143 extern TFtype __extendsfkf2_hw (float);
144 extern TFtype __extenddfkf2_hw (double);
145 extern float __trunckfsf2_hw (TFtype);
146 extern double __trunckfdf2_hw (TFtype);
147 extern SItype_ppc __fixkfsi_hw (TFtype);
148 extern DItype_ppc __fixkfdi_hw (TFtype);
149 extern USItype_ppc __fixunskfsi_hw (TFtype);
150 extern UDItype_ppc __fixunskfdi_hw (TFtype);
151 extern TFtype __floatsikf_hw (SItype_ppc);
152 extern TFtype __floatdikf_hw (DItype_ppc);
153 #ifdef _ARCH_PPC64
154 extern TFtype __floattikf_hw (TItype_ppc);
155 #endif
156 extern TFtype __floatunsikf_hw (USItype_ppc);
157 extern TFtype __floatundikf_hw (UDItype_ppc);
158 #ifdef _ARCH_PPC64
159 extern TFtype __floatuntikf_hw (UTItype_ppc);
160 extern TItype_ppc __fixkfti_hw (TFtype);
161 extern UTItype_ppc __fixunskfti_hw (TFtype);
162 #endif
163 extern IBM128_TYPE __extendkftf2_hw (TFtype);
164 extern TFtype __trunctfkf2_hw (IBM128_TYPE);
165 extern TCtype __mulkc3_hw (TFtype, TFtype, TFtype, TFtype);
166 extern TCtype __divkc3_hw (TFtype, TFtype, TFtype, TFtype);
167
168 /* Ifunc function declarations, to automatically switch between software
169 emulation and hardware support. */
170 extern TFtype __addkf3 (TFtype, TFtype);
171 extern TFtype __subkf3 (TFtype, TFtype);
172 extern TFtype __mulkf3 (TFtype, TFtype);
173 extern TFtype __divkf3 (TFtype, TFtype);
174 extern TFtype __negkf2 (TFtype);
175 extern TFtype __powikf2 (TFtype, SItype_ppc);
176 extern CMPtype __eqkf2 (TFtype, TFtype);
177 extern CMPtype __nekf2 (TFtype, TFtype);
178 extern CMPtype __gekf2 (TFtype, TFtype);
179 extern CMPtype __gtkf2 (TFtype, TFtype);
180 extern CMPtype __lekf2 (TFtype, TFtype);
181 extern CMPtype __ltkf2 (TFtype, TFtype);
182 extern CMPtype __unordkf2 (TFtype, TFtype);
183 extern TFtype __extendsfkf2 (float);
184 extern TFtype __extenddfkf2 (double);
185 extern float __trunckfsf2 (TFtype);
186 extern double __trunckfdf2 (TFtype);
187 extern SItype_ppc __fixkfsi (TFtype);
188 extern DItype_ppc __fixkfdi (TFtype);
189 extern USItype_ppc __fixunskfsi (TFtype);
190 extern UDItype_ppc __fixunskfdi (TFtype);
191 extern TFtype __floatsikf (SItype_ppc);
192 extern TFtype __floatdikf (DItype_ppc);
193 #ifdef _ARCH_PPC64
194 extern TFtype __floattikf (TItype_ppc);
195 #endif
196 extern TFtype __floatunsikf (USItype_ppc);
197 extern TFtype __floatundikf (UDItype_ppc);
198 #ifdef _ARCH_PPC64
199 extern TFtype __floatuntikf (UTItype_ppc);
200 extern TItype_ppc __fixkfti (TFtype);
201 extern UTItype_ppc __fixunskfti (TFtype);
202 #endif
203 extern IBM128_TYPE __extendkftf2 (TFtype);
204 extern TFtype __trunctfkf2 (IBM128_TYPE);
205
206 /* Complex __float128 built on __float128 interfaces. */
207 extern TCtype __mulkc3 (TFtype, TFtype, TFtype, TFtype);
208 extern TCtype __divkc3 (TFtype, TFtype, TFtype, TFtype);
209
210 /* Convert IEEE 128-bit floating point to/from string. We explicitly use
211 _Float128 instead of TFmode because _strtokf and _strfromkf must be compiled
212 with long double being IBM 128. */
213 extern _Float128 __strtokf (const char *, char **);
214 extern int __strfromkf (char *restrict, size_t, const char *restrict,
215 _Float128);
216
217 /* Implementation of conversions between __ibm128 and __float128, to allow the
218 same code to be used on systems with IEEE 128-bit emulation and with IEEE
219 128-bit hardware support. */
220
221 union ibm128_union {
222 IBM128_TYPE ibm128;
223 double dbl[2];
224 };
225
226 #define CVT_FLOAT128_TO_IBM128(RESULT, VALUE) \
227 { \
228 double __high, __low; \
229 TFtype __value = (VALUE); \
230 union ibm128_union u; \
231 \
232 __high = (double) __value; \
233 if (__builtin_isnan (__high) || __builtin_isinf (__high)) \
234 __low = 0.0; \
235 \
236 else \
237 { \
238 double __high_temp; \
239 \
240 __low = (double) (__value - (TFtype) __high); \
241 /* Renormalize low/high and move them into canonical IBM long \
242 double form. */ \
243 __high_temp = __high + __low; \
244 __low = (__high - __high_temp) + __low; \
245 __high = __high_temp; \
246 } \
247 \
248 u.dbl[0] = __high; \
249 u.dbl[1] = __low; \
250 RESULT = u.ibm128; \
251 }
252
253 #define CVT_IBM128_TO_FLOAT128(RESULT, VALUE) \
254 { \
255 union ibm128_union u; \
256 double __high, __low; \
257 \
258 u.ibm128 = (VALUE); \
259 __high = u.dbl[0]; \
260 __low = u.dbl[1]; \
261 \
262 /* Handle the special cases of NAN and infinity. */ \
263 if (__builtin_isnan (__high) || __builtin_isinf (__high)) \
264 RESULT = (TFtype) __high; \
265 \
266 /* If low is 0.0, there no need to do the add. In addition, \
267 avoiding the add produces the correct sign if high is -0.0. */ \
268 else if (__low == 0.0) \
269 RESULT = (TFtype) __high; \
270 \
271 else \
272 RESULT = ((TFtype) __high) + ((TFtype) __low); \
273 }