xref: /openbmc/qemu/tcg/tci/tcg-target.c.inc (revision cba42d61)
1/*
2 * Tiny Code Generator for QEMU
3 *
4 * Copyright (c) 2009, 2011 Stefan Weil
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25/* TODO list:
26 * - See TODO comments in code.
27 */
28
29/* Marker for missing code. */
30#define TODO() \
31    do { \
32        fprintf(stderr, "TODO %s:%u: %s()\n", \
33                __FILE__, __LINE__, __func__); \
34        tcg_abort(); \
35    } while (0)
36
37/* Bitfield n...m (in 32 bit value). */
38#define BITS(n, m) (((0xffffffffU << (31 - n)) >> (31 - n + m)) << m)
39
40static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
41{
42    switch (op) {
43    case INDEX_op_ld8u_i32:
44    case INDEX_op_ld8s_i32:
45    case INDEX_op_ld16u_i32:
46    case INDEX_op_ld16s_i32:
47    case INDEX_op_ld_i32:
48    case INDEX_op_ld8u_i64:
49    case INDEX_op_ld8s_i64:
50    case INDEX_op_ld16u_i64:
51    case INDEX_op_ld16s_i64:
52    case INDEX_op_ld32u_i64:
53    case INDEX_op_ld32s_i64:
54    case INDEX_op_ld_i64:
55    case INDEX_op_not_i32:
56    case INDEX_op_not_i64:
57    case INDEX_op_neg_i32:
58    case INDEX_op_neg_i64:
59    case INDEX_op_ext8s_i32:
60    case INDEX_op_ext8s_i64:
61    case INDEX_op_ext16s_i32:
62    case INDEX_op_ext16s_i64:
63    case INDEX_op_ext8u_i32:
64    case INDEX_op_ext8u_i64:
65    case INDEX_op_ext16u_i32:
66    case INDEX_op_ext16u_i64:
67    case INDEX_op_ext32s_i64:
68    case INDEX_op_ext32u_i64:
69    case INDEX_op_ext_i32_i64:
70    case INDEX_op_extu_i32_i64:
71    case INDEX_op_bswap16_i32:
72    case INDEX_op_bswap16_i64:
73    case INDEX_op_bswap32_i32:
74    case INDEX_op_bswap32_i64:
75    case INDEX_op_bswap64_i64:
76        return C_O1_I1(r, r);
77
78    case INDEX_op_st8_i32:
79    case INDEX_op_st16_i32:
80    case INDEX_op_st_i32:
81    case INDEX_op_st8_i64:
82    case INDEX_op_st16_i64:
83    case INDEX_op_st32_i64:
84    case INDEX_op_st_i64:
85        return C_O0_I2(r, r);
86
87    case INDEX_op_div_i32:
88    case INDEX_op_div_i64:
89    case INDEX_op_divu_i32:
90    case INDEX_op_divu_i64:
91    case INDEX_op_rem_i32:
92    case INDEX_op_rem_i64:
93    case INDEX_op_remu_i32:
94    case INDEX_op_remu_i64:
95    case INDEX_op_add_i32:
96    case INDEX_op_add_i64:
97    case INDEX_op_sub_i32:
98    case INDEX_op_sub_i64:
99    case INDEX_op_mul_i32:
100    case INDEX_op_mul_i64:
101    case INDEX_op_and_i32:
102    case INDEX_op_and_i64:
103    case INDEX_op_andc_i32:
104    case INDEX_op_andc_i64:
105    case INDEX_op_eqv_i32:
106    case INDEX_op_eqv_i64:
107    case INDEX_op_nand_i32:
108    case INDEX_op_nand_i64:
109    case INDEX_op_nor_i32:
110    case INDEX_op_nor_i64:
111    case INDEX_op_or_i32:
112    case INDEX_op_or_i64:
113    case INDEX_op_orc_i32:
114    case INDEX_op_orc_i64:
115    case INDEX_op_xor_i32:
116    case INDEX_op_xor_i64:
117    case INDEX_op_shl_i32:
118    case INDEX_op_shl_i64:
119    case INDEX_op_shr_i32:
120    case INDEX_op_shr_i64:
121    case INDEX_op_sar_i32:
122    case INDEX_op_sar_i64:
123    case INDEX_op_rotl_i32:
124    case INDEX_op_rotl_i64:
125    case INDEX_op_rotr_i32:
126    case INDEX_op_rotr_i64:
127    case INDEX_op_setcond_i32:
128    case INDEX_op_setcond_i64:
129        return C_O1_I2(r, r, r);
130
131    case INDEX_op_deposit_i32:
132    case INDEX_op_deposit_i64:
133        return C_O1_I2(r, 0, r);
134
135    case INDEX_op_brcond_i32:
136    case INDEX_op_brcond_i64:
137        return C_O0_I2(r, r);
138
139#if TCG_TARGET_REG_BITS == 32
140    /* TODO: Support R, R, R, R, RI, RI? Will it be faster? */
141    case INDEX_op_add2_i32:
142    case INDEX_op_sub2_i32:
143        return C_O2_I4(r, r, r, r, r, r);
144    case INDEX_op_brcond2_i32:
145        return C_O0_I4(r, r, r, r);
146    case INDEX_op_mulu2_i32:
147        return C_O2_I2(r, r, r, r);
148    case INDEX_op_setcond2_i32:
149        return C_O1_I4(r, r, r, r, r);
150#endif
151
152    case INDEX_op_qemu_ld_i32:
153        return (TARGET_LONG_BITS <= TCG_TARGET_REG_BITS
154                ? C_O1_I1(r, r)
155                : C_O1_I2(r, r, r));
156    case INDEX_op_qemu_ld_i64:
157        return (TCG_TARGET_REG_BITS == 64 ? C_O1_I1(r, r)
158                : TARGET_LONG_BITS <= TCG_TARGET_REG_BITS ? C_O2_I1(r, r, r)
159                : C_O2_I2(r, r, r, r));
160    case INDEX_op_qemu_st_i32:
161        return (TARGET_LONG_BITS <= TCG_TARGET_REG_BITS
162                ? C_O0_I2(r, r)
163                : C_O0_I3(r, r, r));
164    case INDEX_op_qemu_st_i64:
165        return (TCG_TARGET_REG_BITS == 64 ? C_O0_I2(r, r)
166                : TARGET_LONG_BITS <= TCG_TARGET_REG_BITS ? C_O0_I3(r, r, r)
167                : C_O0_I4(r, r, r, r));
168
169    default:
170        g_assert_not_reached();
171    }
172}
173
174static const int tcg_target_reg_alloc_order[] = {
175    TCG_REG_R0,
176    TCG_REG_R1,
177    TCG_REG_R2,
178    TCG_REG_R3,
179    TCG_REG_R4,
180    TCG_REG_R5,
181    TCG_REG_R6,
182    TCG_REG_R7,
183    TCG_REG_R8,
184    TCG_REG_R9,
185    TCG_REG_R10,
186    TCG_REG_R11,
187    TCG_REG_R12,
188    TCG_REG_R13,
189    TCG_REG_R14,
190    TCG_REG_R15,
191};
192
193#if MAX_OPC_PARAM_IARGS != 6
194# error Fix needed, number of supported input arguments changed!
195#endif
196
197static const int tcg_target_call_iarg_regs[] = {
198    TCG_REG_R0,
199    TCG_REG_R1,
200    TCG_REG_R2,
201    TCG_REG_R3,
202    TCG_REG_R4,
203    TCG_REG_R5,
204#if TCG_TARGET_REG_BITS == 32
205    /* 32 bit hosts need 2 * MAX_OPC_PARAM_IARGS registers. */
206    TCG_REG_R6,
207    TCG_REG_R7,
208    TCG_REG_R8,
209    TCG_REG_R9,
210    TCG_REG_R10,
211    TCG_REG_R11,
212#endif
213};
214
215static const int tcg_target_call_oarg_regs[] = {
216    TCG_REG_R0,
217#if TCG_TARGET_REG_BITS == 32
218    TCG_REG_R1
219#endif
220};
221
222#ifdef CONFIG_DEBUG_TCG
223static const char *const tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
224    "r00",
225    "r01",
226    "r02",
227    "r03",
228    "r04",
229    "r05",
230    "r06",
231    "r07",
232    "r08",
233    "r09",
234    "r10",
235    "r11",
236    "r12",
237    "r13",
238    "r14",
239    "r15",
240};
241#endif
242
243static bool patch_reloc(tcg_insn_unit *code_ptr, int type,
244                        intptr_t value, intptr_t addend)
245{
246    /* tcg_out_reloc always uses the same type, addend. */
247    tcg_debug_assert(type == sizeof(tcg_target_long));
248    tcg_debug_assert(addend == 0);
249    tcg_debug_assert(value != 0);
250    if (TCG_TARGET_REG_BITS == 32) {
251        tcg_patch32(code_ptr, value);
252    } else {
253        tcg_patch64(code_ptr, value);
254    }
255    return true;
256}
257
258#if defined(CONFIG_DEBUG_TCG_INTERPRETER)
259/* Show current bytecode. Used by tcg interpreter. */
260void tci_disas(uint8_t opc)
261{
262    const TCGOpDef *def = &tcg_op_defs[opc];
263    fprintf(stderr, "TCG %s %u, %u, %u\n",
264            def->name, def->nb_oargs, def->nb_iargs, def->nb_cargs);
265}
266#endif
267
268/* Write value (native size). */
269static void tcg_out_i(TCGContext *s, tcg_target_ulong v)
270{
271    if (TCG_TARGET_REG_BITS == 32) {
272        tcg_out32(s, v);
273    } else {
274        tcg_out64(s, v);
275    }
276}
277
278/* Write opcode. */
279static void tcg_out_op_t(TCGContext *s, TCGOpcode op)
280{
281    tcg_out8(s, op);
282    tcg_out8(s, 0);
283}
284
285/* Write register. */
286static void tcg_out_r(TCGContext *s, TCGArg t0)
287{
288    tcg_debug_assert(t0 < TCG_TARGET_NB_REGS);
289    tcg_out8(s, t0);
290}
291
292/* Write label. */
293static void tci_out_label(TCGContext *s, TCGLabel *label)
294{
295    if (label->has_value) {
296        tcg_out_i(s, label->u.value);
297        tcg_debug_assert(label->u.value);
298    } else {
299        tcg_out_reloc(s, s->code_ptr, sizeof(tcg_target_ulong), label, 0);
300        s->code_ptr += sizeof(tcg_target_ulong);
301    }
302}
303
304static void stack_bounds_check(TCGReg base, target_long offset)
305{
306    if (base == TCG_REG_CALL_STACK) {
307        tcg_debug_assert(offset < 0);
308        tcg_debug_assert(offset >= -(CPU_TEMP_BUF_NLONGS * sizeof(long)));
309    }
310}
311
312static void tcg_out_ld(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg1,
313                       intptr_t arg2)
314{
315    uint8_t *old_code_ptr = s->code_ptr;
316
317    stack_bounds_check(arg1, arg2);
318    if (type == TCG_TYPE_I32) {
319        tcg_out_op_t(s, INDEX_op_ld_i32);
320        tcg_out_r(s, ret);
321        tcg_out_r(s, arg1);
322        tcg_out32(s, arg2);
323    } else {
324        tcg_debug_assert(type == TCG_TYPE_I64);
325#if TCG_TARGET_REG_BITS == 64
326        tcg_out_op_t(s, INDEX_op_ld_i64);
327        tcg_out_r(s, ret);
328        tcg_out_r(s, arg1);
329        tcg_debug_assert(arg2 == (int32_t)arg2);
330        tcg_out32(s, arg2);
331#else
332        TODO();
333#endif
334    }
335    old_code_ptr[1] = s->code_ptr - old_code_ptr;
336}
337
338static bool tcg_out_mov(TCGContext *s, TCGType type, TCGReg ret, TCGReg arg)
339{
340    uint8_t *old_code_ptr = s->code_ptr;
341    tcg_debug_assert(ret != arg);
342#if TCG_TARGET_REG_BITS == 32
343    tcg_out_op_t(s, INDEX_op_mov_i32);
344#else
345    tcg_out_op_t(s, INDEX_op_mov_i64);
346#endif
347    tcg_out_r(s, ret);
348    tcg_out_r(s, arg);
349    old_code_ptr[1] = s->code_ptr - old_code_ptr;
350    return true;
351}
352
353static void tcg_out_movi(TCGContext *s, TCGType type,
354                         TCGReg t0, tcg_target_long arg)
355{
356    uint8_t *old_code_ptr = s->code_ptr;
357    uint32_t arg32 = arg;
358    if (type == TCG_TYPE_I32 || arg == arg32) {
359        tcg_out_op_t(s, INDEX_op_tci_movi_i32);
360        tcg_out_r(s, t0);
361        tcg_out32(s, arg32);
362    } else {
363        tcg_debug_assert(type == TCG_TYPE_I64);
364#if TCG_TARGET_REG_BITS == 64
365        tcg_out_op_t(s, INDEX_op_tci_movi_i64);
366        tcg_out_r(s, t0);
367        tcg_out64(s, arg);
368#else
369        TODO();
370#endif
371    }
372    old_code_ptr[1] = s->code_ptr - old_code_ptr;
373}
374
375static inline void tcg_out_call(TCGContext *s, const tcg_insn_unit *arg)
376{
377    uint8_t *old_code_ptr = s->code_ptr;
378    tcg_out_op_t(s, INDEX_op_call);
379    tcg_out_i(s, (uintptr_t)arg);
380    old_code_ptr[1] = s->code_ptr - old_code_ptr;
381}
382
383#if TCG_TARGET_REG_BITS == 64
384# define CASE_32_64(x) \
385        case glue(glue(INDEX_op_, x), _i64): \
386        case glue(glue(INDEX_op_, x), _i32):
387# define CASE_64(x) \
388        case glue(glue(INDEX_op_, x), _i64):
389#else
390# define CASE_32_64(x) \
391        case glue(glue(INDEX_op_, x), _i32):
392# define CASE_64(x)
393#endif
394
395static void tcg_out_op(TCGContext *s, TCGOpcode opc, const TCGArg *args,
396                       const int *const_args)
397{
398    uint8_t *old_code_ptr = s->code_ptr;
399
400    tcg_out_op_t(s, opc);
401
402    switch (opc) {
403    case INDEX_op_exit_tb:
404        tcg_out64(s, args[0]);
405        break;
406
407    case INDEX_op_goto_tb:
408        if (s->tb_jmp_insn_offset) {
409            /* Direct jump method. */
410            /* Align for atomic patching and thread safety */
411            s->code_ptr = QEMU_ALIGN_PTR_UP(s->code_ptr, 4);
412            s->tb_jmp_insn_offset[args[0]] = tcg_current_code_size(s);
413            tcg_out32(s, 0);
414        } else {
415            /* Indirect jump method. */
416            TODO();
417        }
418        set_jmp_reset_offset(s, args[0]);
419        break;
420
421    case INDEX_op_br:
422        tci_out_label(s, arg_label(args[0]));
423        break;
424
425    CASE_32_64(setcond)
426        tcg_out_r(s, args[0]);
427        tcg_out_r(s, args[1]);
428        tcg_out_r(s, args[2]);
429        tcg_out8(s, args[3]);   /* condition */
430        break;
431
432#if TCG_TARGET_REG_BITS == 32
433    case INDEX_op_setcond2_i32:
434        /* setcond2_i32 cond, t0, t1_low, t1_high, t2_low, t2_high */
435        tcg_out_r(s, args[0]);
436        tcg_out_r(s, args[1]);
437        tcg_out_r(s, args[2]);
438        tcg_out_r(s, args[3]);
439        tcg_out_r(s, args[4]);
440        tcg_out8(s, args[5]);   /* condition */
441        break;
442#endif
443
444    CASE_32_64(ld8u)
445    CASE_32_64(ld8s)
446    CASE_32_64(ld16u)
447    CASE_32_64(ld16s)
448    case INDEX_op_ld_i32:
449    CASE_64(ld32u)
450    CASE_64(ld32s)
451    CASE_64(ld)
452    CASE_32_64(st8)
453    CASE_32_64(st16)
454    case INDEX_op_st_i32:
455    CASE_64(st32)
456    CASE_64(st)
457        stack_bounds_check(args[1], args[2]);
458        tcg_out_r(s, args[0]);
459        tcg_out_r(s, args[1]);
460        tcg_debug_assert(args[2] == (int32_t)args[2]);
461        tcg_out32(s, args[2]);
462        break;
463
464    CASE_32_64(add)
465    CASE_32_64(sub)
466    CASE_32_64(mul)
467    CASE_32_64(and)
468    CASE_32_64(or)
469    CASE_32_64(xor)
470    CASE_32_64(andc)     /* Optional (TCG_TARGET_HAS_andc_*). */
471    CASE_32_64(orc)      /* Optional (TCG_TARGET_HAS_orc_*). */
472    CASE_32_64(eqv)      /* Optional (TCG_TARGET_HAS_eqv_*). */
473    CASE_32_64(nand)     /* Optional (TCG_TARGET_HAS_nand_*). */
474    CASE_32_64(nor)      /* Optional (TCG_TARGET_HAS_nor_*). */
475    CASE_32_64(shl)
476    CASE_32_64(shr)
477    CASE_32_64(sar)
478    CASE_32_64(rotl)     /* Optional (TCG_TARGET_HAS_rot_*). */
479    CASE_32_64(rotr)     /* Optional (TCG_TARGET_HAS_rot_*). */
480    CASE_32_64(div)      /* Optional (TCG_TARGET_HAS_div_*). */
481    CASE_32_64(divu)     /* Optional (TCG_TARGET_HAS_div_*). */
482    CASE_32_64(rem)      /* Optional (TCG_TARGET_HAS_div_*). */
483    CASE_32_64(remu)     /* Optional (TCG_TARGET_HAS_div_*). */
484        tcg_out_r(s, args[0]);
485        tcg_out_r(s, args[1]);
486        tcg_out_r(s, args[2]);
487        break;
488
489    CASE_32_64(deposit)  /* Optional (TCG_TARGET_HAS_deposit_*). */
490        tcg_out_r(s, args[0]);
491        tcg_out_r(s, args[1]);
492        tcg_out_r(s, args[2]);
493        tcg_debug_assert(args[3] <= UINT8_MAX);
494        tcg_out8(s, args[3]);
495        tcg_debug_assert(args[4] <= UINT8_MAX);
496        tcg_out8(s, args[4]);
497        break;
498
499    CASE_32_64(brcond)
500        tcg_out_r(s, args[0]);
501        tcg_out_r(s, args[1]);
502        tcg_out8(s, args[2]);           /* condition */
503        tci_out_label(s, arg_label(args[3]));
504        break;
505
506    CASE_32_64(neg)      /* Optional (TCG_TARGET_HAS_neg_*). */
507    CASE_32_64(not)      /* Optional (TCG_TARGET_HAS_not_*). */
508    CASE_32_64(ext8s)    /* Optional (TCG_TARGET_HAS_ext8s_*). */
509    CASE_32_64(ext8u)    /* Optional (TCG_TARGET_HAS_ext8u_*). */
510    CASE_32_64(ext16s)   /* Optional (TCG_TARGET_HAS_ext16s_*). */
511    CASE_32_64(ext16u)   /* Optional (TCG_TARGET_HAS_ext16u_*). */
512    CASE_64(ext32s)      /* Optional (TCG_TARGET_HAS_ext32s_i64). */
513    CASE_64(ext32u)      /* Optional (TCG_TARGET_HAS_ext32u_i64). */
514    CASE_64(ext_i32)
515    CASE_64(extu_i32)
516    CASE_32_64(bswap16)  /* Optional (TCG_TARGET_HAS_bswap16_*). */
517    CASE_32_64(bswap32)  /* Optional (TCG_TARGET_HAS_bswap32_*). */
518    CASE_64(bswap64)     /* Optional (TCG_TARGET_HAS_bswap64_i64). */
519        tcg_out_r(s, args[0]);
520        tcg_out_r(s, args[1]);
521        break;
522
523#if TCG_TARGET_REG_BITS == 32
524    case INDEX_op_add2_i32:
525    case INDEX_op_sub2_i32:
526        tcg_out_r(s, args[0]);
527        tcg_out_r(s, args[1]);
528        tcg_out_r(s, args[2]);
529        tcg_out_r(s, args[3]);
530        tcg_out_r(s, args[4]);
531        tcg_out_r(s, args[5]);
532        break;
533    case INDEX_op_brcond2_i32:
534        tcg_out_r(s, args[0]);
535        tcg_out_r(s, args[1]);
536        tcg_out_r(s, args[2]);
537        tcg_out_r(s, args[3]);
538        tcg_out8(s, args[4]);           /* condition */
539        tci_out_label(s, arg_label(args[5]));
540        break;
541    case INDEX_op_mulu2_i32:
542        tcg_out_r(s, args[0]);
543        tcg_out_r(s, args[1]);
544        tcg_out_r(s, args[2]);
545        tcg_out_r(s, args[3]);
546        break;
547#endif
548
549    case INDEX_op_qemu_ld_i32:
550    case INDEX_op_qemu_st_i32:
551        tcg_out_r(s, *args++);
552        tcg_out_r(s, *args++);
553        if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
554            tcg_out_r(s, *args++);
555        }
556        tcg_out_i(s, *args++);
557        break;
558
559    case INDEX_op_qemu_ld_i64:
560    case INDEX_op_qemu_st_i64:
561        tcg_out_r(s, *args++);
562        if (TCG_TARGET_REG_BITS == 32) {
563            tcg_out_r(s, *args++);
564        }
565        tcg_out_r(s, *args++);
566        if (TARGET_LONG_BITS > TCG_TARGET_REG_BITS) {
567            tcg_out_r(s, *args++);
568        }
569        tcg_out_i(s, *args++);
570        break;
571
572    case INDEX_op_mb:
573        break;
574
575    case INDEX_op_mov_i32:  /* Always emitted via tcg_out_mov.  */
576    case INDEX_op_mov_i64:
577    case INDEX_op_call:     /* Always emitted via tcg_out_call.  */
578    default:
579        tcg_abort();
580    }
581    old_code_ptr[1] = s->code_ptr - old_code_ptr;
582}
583
584static void tcg_out_st(TCGContext *s, TCGType type, TCGReg arg, TCGReg arg1,
585                       intptr_t arg2)
586{
587    uint8_t *old_code_ptr = s->code_ptr;
588
589    stack_bounds_check(arg1, arg2);
590    if (type == TCG_TYPE_I32) {
591        tcg_out_op_t(s, INDEX_op_st_i32);
592        tcg_out_r(s, arg);
593        tcg_out_r(s, arg1);
594        tcg_out32(s, arg2);
595    } else {
596        tcg_debug_assert(type == TCG_TYPE_I64);
597#if TCG_TARGET_REG_BITS == 64
598        tcg_out_op_t(s, INDEX_op_st_i64);
599        tcg_out_r(s, arg);
600        tcg_out_r(s, arg1);
601        tcg_out32(s, arg2);
602#else
603        TODO();
604#endif
605    }
606    old_code_ptr[1] = s->code_ptr - old_code_ptr;
607}
608
609static inline bool tcg_out_sti(TCGContext *s, TCGType type, TCGArg val,
610                               TCGReg base, intptr_t ofs)
611{
612    return false;
613}
614
615/* Test if a constant matches the constraint. */
616static int tcg_target_const_match(tcg_target_long val, TCGType type,
617                                  const TCGArgConstraint *arg_ct)
618{
619    /* No need to return 0 or 1, 0 or != 0 is good enough. */
620    return arg_ct->ct & TCG_CT_CONST;
621}
622
623static void tcg_target_init(TCGContext *s)
624{
625#if defined(CONFIG_DEBUG_TCG_INTERPRETER)
626    const char *envval = getenv("DEBUG_TCG");
627    if (envval) {
628        qemu_set_log(strtol(envval, NULL, 0));
629    }
630#endif
631
632    /* The current code uses uint8_t for tcg operations. */
633    tcg_debug_assert(tcg_op_defs_max <= UINT8_MAX);
634
635    /* Registers available for 32 bit operations. */
636    tcg_target_available_regs[TCG_TYPE_I32] = BIT(TCG_TARGET_NB_REGS) - 1;
637    /* Registers available for 64 bit operations. */
638    tcg_target_available_regs[TCG_TYPE_I64] = BIT(TCG_TARGET_NB_REGS) - 1;
639    /* TODO: Which registers should be set here? */
640    tcg_target_call_clobber_regs = BIT(TCG_TARGET_NB_REGS) - 1;
641
642    s->reserved_regs = 0;
643    tcg_regset_set_reg(s->reserved_regs, TCG_REG_CALL_STACK);
644
645    /* We use negative offsets from "sp" so that we can distinguish
646       stores that might pretend to be call arguments.  */
647    tcg_set_frame(s, TCG_REG_CALL_STACK,
648                  -CPU_TEMP_BUF_NLONGS * sizeof(long),
649                  CPU_TEMP_BUF_NLONGS * sizeof(long));
650}
651
652/* Generate global QEMU prologue and epilogue code. */
653static inline void tcg_target_qemu_prologue(TCGContext *s)
654{
655}
656