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7b0c0d66 TM |
1 | /* |
2 | * PowerPC Decimal Floating Point (DPF) emulation helpers for QEMU. | |
3 | * | |
4 | * Copyright (c) 2014 IBM Corporation. | |
5 | * | |
6 | * This library is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2 of the License, or (at your option) any later version. | |
10 | * | |
11 | * This library is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with this library; if not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include "cpu.h" | |
21 | #include "exec/helper-proto.h" | |
22 | ||
23 | #define DECNUMDIGITS 34 | |
24 | #include "libdecnumber/decContext.h" | |
25 | #include "libdecnumber/decNumber.h" | |
26 | #include "libdecnumber/dpd/decimal32.h" | |
27 | #include "libdecnumber/dpd/decimal64.h" | |
28 | #include "libdecnumber/dpd/decimal128.h" | |
29 | ||
30 | #if defined(HOST_WORDS_BIGENDIAN) | |
31 | #define HI_IDX 0 | |
32 | #define LO_IDX 1 | |
33 | #else | |
34 | #define HI_IDX 1 | |
35 | #define LO_IDX 0 | |
36 | #endif | |
37 | ||
38 | struct PPC_DFP { | |
39 | CPUPPCState *env; | |
40 | uint64_t t64[2], a64[2], b64[2]; | |
41 | decNumber t, a, b; | |
42 | decContext context; | |
43 | uint8_t crbf; | |
44 | }; | |
45 | ||
46 | static void dfp_prepare_rounding_mode(decContext *context, uint64_t fpscr) | |
47 | { | |
48 | enum rounding rnd; | |
49 | ||
50 | switch ((fpscr >> 32) & 0x7) { | |
51 | case 0: | |
52 | rnd = DEC_ROUND_HALF_EVEN; | |
53 | break; | |
54 | case 1: | |
55 | rnd = DEC_ROUND_DOWN; | |
56 | break; | |
57 | case 2: | |
58 | rnd = DEC_ROUND_CEILING; | |
59 | break; | |
60 | case 3: | |
61 | rnd = DEC_ROUND_FLOOR; | |
62 | break; | |
63 | case 4: | |
64 | rnd = DEC_ROUND_HALF_UP; | |
65 | break; | |
66 | case 5: | |
67 | rnd = DEC_ROUND_HALF_DOWN; | |
68 | break; | |
69 | case 6: | |
70 | rnd = DEC_ROUND_UP; | |
71 | break; | |
72 | case 7: | |
73 | rnd = DEC_ROUND_05UP; | |
74 | break; | |
75 | default: | |
76 | g_assert_not_reached(); | |
77 | } | |
78 | ||
79 | decContextSetRounding(context, rnd); | |
80 | } | |
81 | ||
7b0c0d66 TM |
82 | static void dfp_prepare_decimal64(struct PPC_DFP *dfp, uint64_t *a, |
83 | uint64_t *b, CPUPPCState *env) | |
84 | { | |
85 | decContextDefault(&dfp->context, DEC_INIT_DECIMAL64); | |
86 | dfp_prepare_rounding_mode(&dfp->context, env->fpscr); | |
87 | dfp->env = env; | |
88 | ||
89 | if (a) { | |
90 | dfp->a64[0] = *a; | |
91 | decimal64ToNumber((decimal64 *)dfp->a64, &dfp->a); | |
92 | } else { | |
93 | dfp->a64[0] = 0; | |
94 | decNumberZero(&dfp->a); | |
95 | } | |
96 | ||
97 | if (b) { | |
98 | dfp->b64[0] = *b; | |
99 | decimal64ToNumber((decimal64 *)dfp->b64, &dfp->b); | |
100 | } else { | |
101 | dfp->b64[0] = 0; | |
102 | decNumberZero(&dfp->b); | |
103 | } | |
104 | } | |
105 | ||
7b0c0d66 TM |
106 | static void dfp_prepare_decimal128(struct PPC_DFP *dfp, uint64_t *a, |
107 | uint64_t *b, CPUPPCState *env) | |
108 | { | |
109 | decContextDefault(&dfp->context, DEC_INIT_DECIMAL128); | |
110 | dfp_prepare_rounding_mode(&dfp->context, env->fpscr); | |
111 | dfp->env = env; | |
112 | ||
113 | if (a) { | |
114 | dfp->a64[0] = a[HI_IDX]; | |
115 | dfp->a64[1] = a[LO_IDX]; | |
116 | decimal128ToNumber((decimal128 *)dfp->a64, &dfp->a); | |
117 | } else { | |
118 | dfp->a64[0] = dfp->a64[1] = 0; | |
119 | decNumberZero(&dfp->a); | |
120 | } | |
121 | ||
122 | if (b) { | |
123 | dfp->b64[0] = b[HI_IDX]; | |
124 | dfp->b64[1] = b[LO_IDX]; | |
125 | decimal128ToNumber((decimal128 *)dfp->b64, &dfp->b); | |
126 | } else { | |
127 | dfp->b64[0] = dfp->b64[1] = 0; | |
128 | decNumberZero(&dfp->b); | |
129 | } | |
130 | } | |
27722744 TM |
131 | |
132 | #define FP_FX (1ull << FPSCR_FX) | |
133 | #define FP_FEX (1ull << FPSCR_FEX) | |
134 | #define FP_OX (1ull << FPSCR_OX) | |
135 | #define FP_OE (1ull << FPSCR_OE) | |
136 | #define FP_UX (1ull << FPSCR_UX) | |
137 | #define FP_UE (1ull << FPSCR_UE) | |
138 | #define FP_XX (1ull << FPSCR_XX) | |
139 | #define FP_XE (1ull << FPSCR_XE) | |
140 | #define FP_ZX (1ull << FPSCR_ZX) | |
141 | #define FP_ZE (1ull << FPSCR_ZE) | |
142 | #define FP_VX (1ull << FPSCR_VX) | |
143 | #define FP_VXSNAN (1ull << FPSCR_VXSNAN) | |
144 | #define FP_VXISI (1ull << FPSCR_VXISI) | |
145 | #define FP_VXIMZ (1ull << FPSCR_VXIMZ) | |
146 | #define FP_VXZDZ (1ull << FPSCR_VXZDZ) | |
147 | #define FP_VXIDI (1ull << FPSCR_VXIDI) | |
148 | #define FP_VXVC (1ull << FPSCR_VXVC) | |
149 | #define FP_VXCVI (1ull << FPSCR_VXCVI) | |
150 | #define FP_VE (1ull << FPSCR_VE) | |
151 | #define FP_FI (1ull << FPSCR_FI) | |
152 | ||
27722744 TM |
153 | static void dfp_set_FPSCR_flag(struct PPC_DFP *dfp, uint64_t flag, |
154 | uint64_t enabled) | |
155 | { | |
156 | dfp->env->fpscr |= (flag | FP_FX); | |
157 | if (dfp->env->fpscr & enabled) { | |
158 | dfp->env->fpscr |= FP_FEX; | |
159 | } | |
160 | } | |
a9d7ba03 TM |
161 | |
162 | static void dfp_set_FPRF_from_FRT_with_context(struct PPC_DFP *dfp, | |
163 | decContext *context) | |
164 | { | |
165 | uint64_t fprf = 0; | |
166 | ||
167 | /* construct FPRF */ | |
168 | switch (decNumberClass(&dfp->t, context)) { | |
169 | case DEC_CLASS_SNAN: | |
170 | fprf = 0x01; | |
171 | break; | |
172 | case DEC_CLASS_QNAN: | |
173 | fprf = 0x11; | |
174 | break; | |
175 | case DEC_CLASS_NEG_INF: | |
176 | fprf = 0x09; | |
177 | break; | |
178 | case DEC_CLASS_NEG_NORMAL: | |
179 | fprf = 0x08; | |
180 | break; | |
181 | case DEC_CLASS_NEG_SUBNORMAL: | |
182 | fprf = 0x18; | |
183 | break; | |
184 | case DEC_CLASS_NEG_ZERO: | |
185 | fprf = 0x12; | |
186 | break; | |
187 | case DEC_CLASS_POS_ZERO: | |
188 | fprf = 0x02; | |
189 | break; | |
190 | case DEC_CLASS_POS_SUBNORMAL: | |
191 | fprf = 0x14; | |
192 | break; | |
193 | case DEC_CLASS_POS_NORMAL: | |
194 | fprf = 0x04; | |
195 | break; | |
196 | case DEC_CLASS_POS_INF: | |
197 | fprf = 0x05; | |
198 | break; | |
199 | default: | |
200 | assert(0); /* should never get here */ | |
201 | } | |
202 | dfp->env->fpscr &= ~(0x1F << 12); | |
203 | dfp->env->fpscr |= (fprf << 12); | |
204 | } | |
205 | ||
206 | static void dfp_set_FPRF_from_FRT(struct PPC_DFP *dfp) | |
207 | { | |
208 | dfp_set_FPRF_from_FRT_with_context(dfp, &dfp->context); | |
209 | } | |
210 | ||
211 | static void dfp_check_for_OX(struct PPC_DFP *dfp) | |
212 | { | |
213 | if (dfp->context.status & DEC_Overflow) { | |
214 | dfp_set_FPSCR_flag(dfp, FP_OX, FP_OE); | |
215 | } | |
216 | } | |
217 | ||
218 | static void dfp_check_for_UX(struct PPC_DFP *dfp) | |
219 | { | |
220 | if (dfp->context.status & DEC_Underflow) { | |
221 | dfp_set_FPSCR_flag(dfp, FP_UX, FP_UE); | |
222 | } | |
223 | } | |
224 | ||
225 | static void dfp_check_for_XX(struct PPC_DFP *dfp) | |
226 | { | |
227 | if (dfp->context.status & DEC_Inexact) { | |
228 | dfp_set_FPSCR_flag(dfp, FP_XX | FP_FI, FP_XE); | |
229 | } | |
230 | } | |
231 | ||
232 | static void dfp_check_for_VXSNAN(struct PPC_DFP *dfp) | |
233 | { | |
234 | if (dfp->context.status & DEC_Invalid_operation) { | |
235 | if (decNumberIsSNaN(&dfp->a) || decNumberIsSNaN(&dfp->b)) { | |
236 | dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXSNAN, FP_VE); | |
237 | } | |
238 | } | |
239 | } | |
240 | ||
241 | static void dfp_check_for_VXISI(struct PPC_DFP *dfp, int testForSameSign) | |
242 | { | |
243 | if (dfp->context.status & DEC_Invalid_operation) { | |
244 | if (decNumberIsInfinite(&dfp->a) && decNumberIsInfinite(&dfp->b)) { | |
245 | int same = decNumberClass(&dfp->a, &dfp->context) == | |
246 | decNumberClass(&dfp->b, &dfp->context); | |
247 | if ((same && testForSameSign) || (!same && !testForSameSign)) { | |
248 | dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXISI, FP_VE); | |
249 | } | |
250 | } | |
251 | } | |
252 | } | |
253 | ||
254 | static void dfp_check_for_VXISI_add(struct PPC_DFP *dfp) | |
255 | { | |
256 | dfp_check_for_VXISI(dfp, 0); | |
257 | } | |
258 | ||
2128f8a5 TM |
259 | static void dfp_check_for_VXISI_subtract(struct PPC_DFP *dfp) |
260 | { | |
261 | dfp_check_for_VXISI(dfp, 1); | |
262 | } | |
263 | ||
8de6a1cc TM |
264 | static void dfp_check_for_VXIMZ(struct PPC_DFP *dfp) |
265 | { | |
266 | if (dfp->context.status & DEC_Invalid_operation) { | |
267 | if ((decNumberIsInfinite(&dfp->a) && decNumberIsZero(&dfp->b)) || | |
268 | (decNumberIsInfinite(&dfp->b) && decNumberIsZero(&dfp->a))) { | |
269 | dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXIMZ, FP_VE); | |
270 | } | |
271 | } | |
272 | } | |
273 | ||
a9d7ba03 TM |
274 | #define DFP_HELPER_TAB(op, dnop, postprocs, size) \ |
275 | void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, uint64_t *b) \ | |
276 | { \ | |
277 | struct PPC_DFP dfp; \ | |
278 | dfp_prepare_decimal##size(&dfp, a, b, env); \ | |
279 | dnop(&dfp.t, &dfp.a, &dfp.b, &dfp.context); \ | |
280 | decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, &dfp.context); \ | |
281 | postprocs(&dfp); \ | |
282 | if (size == 64) { \ | |
283 | t[0] = dfp.t64[0]; \ | |
284 | } else if (size == 128) { \ | |
285 | t[0] = dfp.t64[HI_IDX]; \ | |
286 | t[1] = dfp.t64[LO_IDX]; \ | |
287 | } \ | |
288 | } | |
289 | ||
290 | static void ADD_PPs(struct PPC_DFP *dfp) | |
291 | { | |
292 | dfp_set_FPRF_from_FRT(dfp); | |
293 | dfp_check_for_OX(dfp); | |
294 | dfp_check_for_UX(dfp); | |
295 | dfp_check_for_XX(dfp); | |
296 | dfp_check_for_VXSNAN(dfp); | |
297 | dfp_check_for_VXISI_add(dfp); | |
298 | } | |
299 | ||
300 | DFP_HELPER_TAB(dadd, decNumberAdd, ADD_PPs, 64) | |
301 | DFP_HELPER_TAB(daddq, decNumberAdd, ADD_PPs, 128) | |
2128f8a5 TM |
302 | |
303 | static void SUB_PPs(struct PPC_DFP *dfp) | |
304 | { | |
305 | dfp_set_FPRF_from_FRT(dfp); | |
306 | dfp_check_for_OX(dfp); | |
307 | dfp_check_for_UX(dfp); | |
308 | dfp_check_for_XX(dfp); | |
309 | dfp_check_for_VXSNAN(dfp); | |
310 | dfp_check_for_VXISI_subtract(dfp); | |
311 | } | |
312 | ||
313 | DFP_HELPER_TAB(dsub, decNumberSubtract, SUB_PPs, 64) | |
314 | DFP_HELPER_TAB(dsubq, decNumberSubtract, SUB_PPs, 128) | |
8de6a1cc TM |
315 | |
316 | static void MUL_PPs(struct PPC_DFP *dfp) | |
317 | { | |
318 | dfp_set_FPRF_from_FRT(dfp); | |
319 | dfp_check_for_OX(dfp); | |
320 | dfp_check_for_UX(dfp); | |
321 | dfp_check_for_XX(dfp); | |
322 | dfp_check_for_VXSNAN(dfp); | |
323 | dfp_check_for_VXIMZ(dfp); | |
324 | } | |
325 | ||
326 | DFP_HELPER_TAB(dmul, decNumberMultiply, MUL_PPs, 64) | |
327 | DFP_HELPER_TAB(dmulq, decNumberMultiply, MUL_PPs, 128) |