]> Git Repo - qemu.git/blame - target-ppc/dfp_helper.c
target-ppc: Introduce DFP Compares
[qemu.git] / target-ppc / dfp_helper.c
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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
38struct 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
46static 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
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82static 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
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106static 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}
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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
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153static 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}
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161
162static 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
206static void dfp_set_FPRF_from_FRT(struct PPC_DFP *dfp)
207{
208 dfp_set_FPRF_from_FRT_with_context(dfp, &dfp->context);
209}
210
211static 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
218static 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
225static 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
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232static void dfp_check_for_ZX(struct PPC_DFP *dfp)
233{
234 if (dfp->context.status & DEC_Division_by_zero) {
235 dfp_set_FPSCR_flag(dfp, FP_ZX, FP_ZE);
236 }
237}
238
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239static void dfp_check_for_VXSNAN(struct PPC_DFP *dfp)
240{
241 if (dfp->context.status & DEC_Invalid_operation) {
242 if (decNumberIsSNaN(&dfp->a) || decNumberIsSNaN(&dfp->b)) {
243 dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXSNAN, FP_VE);
244 }
245 }
246}
247
248static void dfp_check_for_VXISI(struct PPC_DFP *dfp, int testForSameSign)
249{
250 if (dfp->context.status & DEC_Invalid_operation) {
251 if (decNumberIsInfinite(&dfp->a) && decNumberIsInfinite(&dfp->b)) {
252 int same = decNumberClass(&dfp->a, &dfp->context) ==
253 decNumberClass(&dfp->b, &dfp->context);
254 if ((same && testForSameSign) || (!same && !testForSameSign)) {
255 dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXISI, FP_VE);
256 }
257 }
258 }
259}
260
261static void dfp_check_for_VXISI_add(struct PPC_DFP *dfp)
262{
263 dfp_check_for_VXISI(dfp, 0);
264}
265
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266static void dfp_check_for_VXISI_subtract(struct PPC_DFP *dfp)
267{
268 dfp_check_for_VXISI(dfp, 1);
269}
270
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271static void dfp_check_for_VXIMZ(struct PPC_DFP *dfp)
272{
273 if (dfp->context.status & DEC_Invalid_operation) {
274 if ((decNumberIsInfinite(&dfp->a) && decNumberIsZero(&dfp->b)) ||
275 (decNumberIsInfinite(&dfp->b) && decNumberIsZero(&dfp->a))) {
276 dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXIMZ, FP_VE);
277 }
278 }
279}
280
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281static void dfp_check_for_VXZDZ(struct PPC_DFP *dfp)
282{
283 if (dfp->context.status & DEC_Division_undefined) {
284 dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXZDZ, FP_VE);
285 }
286}
287
288static void dfp_check_for_VXIDI(struct PPC_DFP *dfp)
289{
290 if (dfp->context.status & DEC_Invalid_operation) {
291 if (decNumberIsInfinite(&dfp->a) && decNumberIsInfinite(&dfp->b)) {
292 dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXIDI, FP_VE);
293 }
294 }
295}
296
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297static void dfp_check_for_VXVC(struct PPC_DFP *dfp)
298{
299 if (decNumberIsNaN(&dfp->a) || decNumberIsNaN(&dfp->b)) {
300 dfp_set_FPSCR_flag(dfp, FP_VX | FP_VXVC, FP_VE);
301 }
302}
303
304static void dfp_set_CRBF_from_T(struct PPC_DFP *dfp)
305{
306 if (decNumberIsNaN(&dfp->t)) {
307 dfp->crbf = 1;
308 } else if (decNumberIsZero(&dfp->t)) {
309 dfp->crbf = 2;
310 } else if (decNumberIsNegative(&dfp->t)) {
311 dfp->crbf = 8;
312 } else {
313 dfp->crbf = 4;
314 }
315}
316
317static void dfp_set_FPCC_from_CRBF(struct PPC_DFP *dfp)
318{
319 dfp->env->fpscr &= ~(0xF << 12);
320 dfp->env->fpscr |= (dfp->crbf << 12);
321}
322
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323#define DFP_HELPER_TAB(op, dnop, postprocs, size) \
324void helper_##op(CPUPPCState *env, uint64_t *t, uint64_t *a, uint64_t *b) \
325{ \
326 struct PPC_DFP dfp; \
327 dfp_prepare_decimal##size(&dfp, a, b, env); \
328 dnop(&dfp.t, &dfp.a, &dfp.b, &dfp.context); \
329 decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, &dfp.context); \
330 postprocs(&dfp); \
331 if (size == 64) { \
332 t[0] = dfp.t64[0]; \
333 } else if (size == 128) { \
334 t[0] = dfp.t64[HI_IDX]; \
335 t[1] = dfp.t64[LO_IDX]; \
336 } \
337}
338
339static void ADD_PPs(struct PPC_DFP *dfp)
340{
341 dfp_set_FPRF_from_FRT(dfp);
342 dfp_check_for_OX(dfp);
343 dfp_check_for_UX(dfp);
344 dfp_check_for_XX(dfp);
345 dfp_check_for_VXSNAN(dfp);
346 dfp_check_for_VXISI_add(dfp);
347}
348
349DFP_HELPER_TAB(dadd, decNumberAdd, ADD_PPs, 64)
350DFP_HELPER_TAB(daddq, decNumberAdd, ADD_PPs, 128)
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351
352static void SUB_PPs(struct PPC_DFP *dfp)
353{
354 dfp_set_FPRF_from_FRT(dfp);
355 dfp_check_for_OX(dfp);
356 dfp_check_for_UX(dfp);
357 dfp_check_for_XX(dfp);
358 dfp_check_for_VXSNAN(dfp);
359 dfp_check_for_VXISI_subtract(dfp);
360}
361
362DFP_HELPER_TAB(dsub, decNumberSubtract, SUB_PPs, 64)
363DFP_HELPER_TAB(dsubq, decNumberSubtract, SUB_PPs, 128)
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364
365static void MUL_PPs(struct PPC_DFP *dfp)
366{
367 dfp_set_FPRF_from_FRT(dfp);
368 dfp_check_for_OX(dfp);
369 dfp_check_for_UX(dfp);
370 dfp_check_for_XX(dfp);
371 dfp_check_for_VXSNAN(dfp);
372 dfp_check_for_VXIMZ(dfp);
373}
374
375DFP_HELPER_TAB(dmul, decNumberMultiply, MUL_PPs, 64)
376DFP_HELPER_TAB(dmulq, decNumberMultiply, MUL_PPs, 128)
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377
378static void DIV_PPs(struct PPC_DFP *dfp)
379{
380 dfp_set_FPRF_from_FRT(dfp);
381 dfp_check_for_OX(dfp);
382 dfp_check_for_UX(dfp);
383 dfp_check_for_ZX(dfp);
384 dfp_check_for_XX(dfp);
385 dfp_check_for_VXSNAN(dfp);
386 dfp_check_for_VXZDZ(dfp);
387 dfp_check_for_VXIDI(dfp);
388}
389
390DFP_HELPER_TAB(ddiv, decNumberDivide, DIV_PPs, 64)
391DFP_HELPER_TAB(ddivq, decNumberDivide, DIV_PPs, 128)
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392
393#define DFP_HELPER_BF_AB(op, dnop, postprocs, size) \
394uint32_t helper_##op(CPUPPCState *env, uint64_t *a, uint64_t *b) \
395{ \
396 struct PPC_DFP dfp; \
397 dfp_prepare_decimal##size(&dfp, a, b, env); \
398 dnop(&dfp.t, &dfp.a, &dfp.b, &dfp.context); \
399 decimal##size##FromNumber((decimal##size *)dfp.t64, &dfp.t, &dfp.context); \
400 postprocs(&dfp); \
401 return dfp.crbf; \
402}
403
404static void CMPU_PPs(struct PPC_DFP *dfp)
405{
406 dfp_set_CRBF_from_T(dfp);
407 dfp_set_FPCC_from_CRBF(dfp);
408 dfp_check_for_VXSNAN(dfp);
409}
410
411DFP_HELPER_BF_AB(dcmpu, decNumberCompare, CMPU_PPs, 64)
412DFP_HELPER_BF_AB(dcmpuq, decNumberCompare, CMPU_PPs, 128)
413
414static void CMPO_PPs(struct PPC_DFP *dfp)
415{
416 dfp_set_CRBF_from_T(dfp);
417 dfp_set_FPCC_from_CRBF(dfp);
418 dfp_check_for_VXSNAN(dfp);
419 dfp_check_for_VXVC(dfp);
420}
421
422DFP_HELPER_BF_AB(dcmpo, decNumberCompare, CMPO_PPs, 64)
423DFP_HELPER_BF_AB(dcmpoq, decNumberCompare, CMPO_PPs, 128)
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