asmthumb.c 14.8 KB
Newer Older
Damien's avatar
Damien committed
1
2
3
4
5
#include <stdio.h>
#include <assert.h>
#include <string.h>

#include "misc.h"
6
#include "mpconfig.h"
Damien's avatar
Damien committed
7
8
#include "asmthumb.h"

9
10
11
// wrapper around everything in this file
#if MICROPY_EMIT_THUMB || MICROPY_EMIT_INLINE_THUMB

Damien's avatar
Damien committed
12
13
14
15
16
17
18
19
20
21
22
23
24
#define UNSIGNED_FIT8(x) (((x) & 0xffffff00) == 0)
#define UNSIGNED_FIT16(x) (((x) & 0xffff0000) == 0)
#define SIGNED_FIT8(x) (((x) & 0xffffff80) == 0) || (((x) & 0xffffff80) == 0xffffff80)
#define SIGNED_FIT9(x) (((x) & 0xffffff00) == 0) || (((x) & 0xffffff00) == 0xffffff00)
#define SIGNED_FIT12(x) (((x) & 0xfffff800) == 0) || (((x) & 0xfffff800) == 0xfffff800)

struct _asm_thumb_t {
    int pass;
    uint code_offset;
    uint code_size;
    byte *code_base;
    byte dummy_data[8];

25
    uint max_num_labels;
Damien's avatar
Damien committed
26
27
28
29
30
31
    int *label_offsets;
    int num_locals;
    uint push_reglist;
    uint stack_adjust;
};

32
asm_thumb_t *asm_thumb_new(uint max_num_labels) {
Damien's avatar
Damien committed
33
34
35
36
37
38
39
    asm_thumb_t *as;

    as = m_new(asm_thumb_t, 1);
    as->pass = 0;
    as->code_offset = 0;
    as->code_size = 0;
    as->code_base = NULL;
40
41
    as->max_num_labels = max_num_labels;
    as->label_offsets = m_new(int, max_num_labels);
Damien's avatar
Damien committed
42
43
44
45
46
47
48
    as->num_locals = 0;

    return as;
}

void asm_thumb_free(asm_thumb_t *as, bool free_code) {
    if (free_code) {
49
        m_del(byte, as->code_base, as->code_size);
Damien's avatar
Damien committed
50
51
52
53
54
55
56
57
58
59
60
61
62
    }
    /*
    if (as->label != NULL) {
        int i;
        for (i = 0; i < as->label->len; ++i)
        {
            Label *lab = &g_array_index(as->label, Label, i);
            if (lab->unresolved != NULL)
                g_array_free(lab->unresolved, true);
        }
        g_array_free(as->label, true);
    }
    */
63
    m_del_obj(asm_thumb_t, as);
Damien's avatar
Damien committed
64
65
66
67
68
}

void asm_thumb_start_pass(asm_thumb_t *as, int pass) {
    as->pass = pass;
    as->code_offset = 0;
69
70
    if (pass == ASM_THUMB_PASS_2) {
        memset(as->label_offsets, -1, as->max_num_labels * sizeof(int));
Damien's avatar
Damien committed
71
72
73
74
    }
}

void asm_thumb_end_pass(asm_thumb_t *as) {
75
    if (as->pass == ASM_THUMB_PASS_2) {
Damien's avatar
Damien committed
76
77
78
        // calculate size of code in bytes
        as->code_size = as->code_offset;
        as->code_base = m_new(byte, as->code_size);
79
        //printf("code_size: %u\n", as->code_size);
Damien's avatar
Damien committed
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
    }

    /*
    // check labels are resolved
    if (as->label != NULL)
    {
        int i;
        for (i = 0; i < as->label->len; ++i)
            if (g_array_index(as->label, Label, i).unresolved != NULL)
                return false;
    }
    */
}

// all functions must go through this one to emit bytes
95
STATIC byte *asm_thumb_get_cur_to_write_bytes(asm_thumb_t *as, int num_bytes_to_write) {
Damien's avatar
Damien committed
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
    //printf("emit %d\n", num_bytes_to_write);
    if (as->pass < ASM_THUMB_PASS_3) {
        as->code_offset += num_bytes_to_write;
        return as->dummy_data;
    } else {
        assert(as->code_offset + num_bytes_to_write <= as->code_size);
        byte *c = as->code_base + as->code_offset;
        as->code_offset += num_bytes_to_write;
        return c;
    }
}

uint asm_thumb_get_code_size(asm_thumb_t *as) {
    return as->code_size;
}

void *asm_thumb_get_code(asm_thumb_t *as) {
    // need to set low bit to indicate that it's thumb code
    return (void *)(((machine_uint_t)as->code_base) | 1);
}

/*
118
STATIC void asm_thumb_write_byte_1(asm_thumb_t *as, byte b1) {
Damien's avatar
Damien committed
119
120
121
122
123
124
125
126
127
128
129
    byte *c = asm_thumb_get_cur_to_write_bytes(as, 1);
    c[0] = b1;
}
*/

/*
#define IMM32_L0(x) ((x) & 0xff)
#define IMM32_L1(x) (((x) >> 8) & 0xff)
#define IMM32_L2(x) (((x) >> 16) & 0xff)
#define IMM32_L3(x) (((x) >> 24) & 0xff)

130
STATIC void asm_thumb_write_word32(asm_thumb_t *as, int w32) {
Damien's avatar
Damien committed
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
    byte *c = asm_thumb_get_cur_to_write_bytes(as, 4);
    c[0] = IMM32_L0(w32);
    c[1] = IMM32_L1(w32);
    c[2] = IMM32_L2(w32);
    c[3] = IMM32_L3(w32);
}
*/

// rlolist is a bit map indicating desired lo-registers
#define OP_PUSH_RLIST(rlolist)      (0xb400 | (rlolist))
#define OP_PUSH_RLIST_LR(rlolist)   (0xb400 | 0x0100 | (rlolist))
#define OP_POP_RLIST(rlolist)       (0xbc00 | (rlolist))
#define OP_POP_RLIST_PC(rlolist)    (0xbc00 | 0x0100 | (rlolist))

#define OP_ADD_SP(num_words) (0xb000 | (num_words))
#define OP_SUB_SP(num_words) (0xb080 | (num_words))

void asm_thumb_entry(asm_thumb_t *as, int num_locals) {
    // work out what to push and how many extra space to reserve on stack
    // so that we have enough for all locals and it's aligned an 8-byte boundary
    uint reglist;
    uint stack_adjust;
    if (num_locals < 0) {
        num_locals = 0;
    }
    // don't ppop r0 because it's used for return value
    switch (num_locals) {
        case 0:
            reglist = 0xf2;
            stack_adjust = 0;
            break;

        case 1:
            reglist = 0xf2;
            stack_adjust = 0;
            break;

        case 2:
            reglist = 0xfe;
            stack_adjust = 0;
            break;

        case 3:
            reglist = 0xfe;
            stack_adjust = 0;
            break;

        default:
            reglist = 0xfe;
            stack_adjust = ((num_locals - 3) + 1) & (~1);
            break;
    }
183
    asm_thumb_op16(as, OP_PUSH_RLIST_LR(reglist));
Damien's avatar
Damien committed
184
    if (stack_adjust > 0) {
185
        asm_thumb_op16(as, OP_SUB_SP(stack_adjust));
Damien's avatar
Damien committed
186
187
188
189
190
191
192
193
    }
    as->push_reglist = reglist;
    as->stack_adjust = stack_adjust;
    as->num_locals = num_locals;
}

void asm_thumb_exit(asm_thumb_t *as) {
    if (as->stack_adjust > 0) {
194
        asm_thumb_op16(as, OP_ADD_SP(as->stack_adjust));
Damien's avatar
Damien committed
195
    }
196
    asm_thumb_op16(as, OP_POP_RLIST_PC(as->push_reglist));
Damien's avatar
Damien committed
197
198
}

199
void asm_thumb_label_assign(asm_thumb_t *as, uint label) {
200
201
202
203
204
205
206
207
208
    assert(label < as->max_num_labels);
    if (as->pass == ASM_THUMB_PASS_2) {
        // assign label offset
        assert(as->label_offsets[label] == -1);
        as->label_offsets[label] = as->code_offset;
    } else if (as->pass == ASM_THUMB_PASS_3) {
        // ensure label offset has not changed from PASS_2 to PASS_3
        //printf("l%d: (at %d=%ld)\n", label, as->label_offsets[label], as->code_offset);
        assert(as->label_offsets[label] == as->code_offset);
Damien's avatar
Damien committed
209
210
211
    }
}

212
213
214
215
216
217
218
219
220
221
222
223
224
225
void asm_thumb_align(asm_thumb_t* as, uint align) {
    // TODO fill unused data with NOPs?
    as->code_offset = (as->code_offset + align - 1) & (~(align - 1));
}

void asm_thumb_data(asm_thumb_t* as, uint bytesize, uint val) {
    byte *c = asm_thumb_get_cur_to_write_bytes(as, bytesize);
    // little endian
    for (uint i = 0; i < bytesize; i++) {
        *c++ = val;
        val >>= 8;
    }
}

226
STATIC int get_label_dest(asm_thumb_t *as, uint label) {
227
228
229
230
    assert(label < as->max_num_labels);
    return as->label_offsets[label];
}

231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
void asm_thumb_op16(asm_thumb_t *as, uint op) {
    byte *c = asm_thumb_get_cur_to_write_bytes(as, 2);
    // little endian
    c[0] = op;
    c[1] = op >> 8;
}

void asm_thumb_op32(asm_thumb_t *as, uint op1, uint op2) {
    byte *c = asm_thumb_get_cur_to_write_bytes(as, 4);
    // little endian, op1 then op2
    c[0] = op1;
    c[1] = op1 >> 8;
    c[2] = op2;
    c[3] = op2 >> 8;
}

247
#define OP_FORMAT_2(op, rlo_dest, rlo_src, src_b) ((op) | ((src_b) << 6) | ((rlo_src) << 3) | (rlo_dest))
248

249
void asm_thumb_format_2(asm_thumb_t *as, uint op, uint rlo_dest, uint rlo_src, int src_b) {
Damien's avatar
Damien committed
250
    assert(rlo_dest < REG_R8);
251
    assert(rlo_src < REG_R8);
252
    asm_thumb_op16(as, OP_FORMAT_2(op, rlo_dest, rlo_src, src_b));
Damien's avatar
Damien committed
253
254
}

255
#define OP_FORMAT_3(op, rlo, i8) ((op) | ((rlo) << 8) | (i8))
256

257
258
void asm_thumb_format_3(asm_thumb_t *as, uint op, uint rlo, int i8) {
    assert(rlo < REG_R8);
259
    asm_thumb_op16(as, OP_FORMAT_3(op, rlo, i8));
Damien's avatar
Damien committed
260
261
}

262
263
264
265
266
#define OP_FORMAT_4(op, rlo_dest, rlo_src) ((op) | ((rlo_src) << 3) | (rlo_dest))

void asm_thumb_format_4(asm_thumb_t *as, uint op, uint rlo_dest, uint rlo_src) {
    assert(rlo_dest < REG_R8);
    assert(rlo_src < REG_R8);
267
    asm_thumb_op16(as, OP_FORMAT_4(op, rlo_dest, rlo_src));
Damien's avatar
Damien committed
268
269
}

270
271
272
#define OP_FORMAT_9_10(op, rlo_dest, rlo_base, offset) ((op) | (((offset) << 6) & 0x07c0) | ((rlo_base) << 3) | (rlo_dest))

void asm_thumb_format_9_10(asm_thumb_t *as, uint op, uint rlo_dest, uint rlo_base, uint offset) {
273
    asm_thumb_op16(as, OP_FORMAT_9_10(op, rlo_dest, rlo_base, offset));
Damien's avatar
Damien committed
274
275
276
277
278
279
280
281
282
283
284
285
286
287
}

void asm_thumb_mov_reg_reg(asm_thumb_t *as, uint reg_dest, uint reg_src) {
    uint op_lo;
    if (reg_src < 8) {
        op_lo = reg_src << 3;
    } else {
        op_lo = 0x40 | ((reg_src - 8) << 3);
    }
    if (reg_dest < 8) {
        op_lo |= reg_dest;
    } else {
        op_lo |= 0x80 | (reg_dest - 8);
    }
288
    // mov reg_dest, reg_src
289
    asm_thumb_op16(as, 0x4600 | op_lo);
Damien's avatar
Damien committed
290
291
}

292
293
#define OP_MOVW (0xf240)
#define OP_MOVT (0xf2c0)
294

295
296
297
298
// if loading lo half with movw, the i16 value will be zero extended into the r32 register!
STATIC void asm_thumb_mov_reg_i16(asm_thumb_t *as, uint mov_op, uint reg_dest, int i16_src) {
    assert(reg_dest < REG_R15);
    // mov[wt] reg_dest, #i16_src
299
    asm_thumb_op32(as, mov_op | ((i16_src >> 1) & 0x0400) | ((i16_src >> 12) & 0xf), ((i16_src << 4) & 0x7000) | (reg_dest << 8) | (i16_src & 0xff));
300
301
}

302
303
304
// the i16_src value will be zero extended into the r32 register!
void asm_thumb_movw_reg_i16(asm_thumb_t *as, uint reg_dest, int i16_src) {
    asm_thumb_mov_reg_i16(as, OP_MOVW, reg_dest, i16_src);
305
306
}

307
308
309
// the i16_src value will be zero extended into the r32 register!
void asm_thumb_movt_reg_i16(asm_thumb_t *as, uint reg_dest, int i16_src) {
    asm_thumb_mov_reg_i16(as, OP_MOVT, reg_dest, i16_src);
310
311
}

312
void asm_thumb_ite_ge(asm_thumb_t *as) {
313
    asm_thumb_op16(as, 0xbfac);
314
315
}

Damien's avatar
Damien committed
316
317
#define OP_B_N(byte_offset) (0xe000 | (((byte_offset) >> 1) & 0x07ff))

318
void asm_thumb_b_n(asm_thumb_t *as, uint label) {
Damien's avatar
Damien committed
319
320
321
322
    int dest = get_label_dest(as, label);
    int rel = dest - as->code_offset;
    rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
    if (SIGNED_FIT12(rel)) {
323
        asm_thumb_op16(as, OP_B_N(rel));
Damien's avatar
Damien committed
324
325
326
327
328
    } else {
        printf("asm_thumb_b_n: branch does not fit in 12 bits\n");
    }
}

329
330
#define OP_BCC_N(cond, byte_offset) (0xd000 | ((cond) << 8) | (((byte_offset) >> 1) & 0x00ff))

331
void asm_thumb_bcc_n(asm_thumb_t *as, int cond, uint label) {
332
333
334
335
    int dest = get_label_dest(as, label);
    int rel = dest - as->code_offset;
    rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
    if (SIGNED_FIT9(rel)) {
336
        asm_thumb_op16(as, OP_BCC_N(cond, rel));
337
    } else {
338
        printf("asm_thumb_bcc_n: branch does not fit in 9 bits\n");
339
340
341
342
343
344
345
346
347
348
349
350
351
    }
}

void asm_thumb_mov_reg_i32(asm_thumb_t *as, uint reg_dest, machine_uint_t i32) {
    // movw, movt does it in 8 bytes
    // ldr [pc, #], dw does it in 6 bytes, but we might not reach to end of code for dw

    asm_thumb_mov_reg_i16(as, OP_MOVW, reg_dest, i32);
    asm_thumb_mov_reg_i16(as, OP_MOVT, reg_dest, i32 >> 16);
}

void asm_thumb_mov_reg_i32_optimised(asm_thumb_t *as, uint reg_dest, int i32) {
    if (reg_dest < 8 && UNSIGNED_FIT8(i32)) {
352
        asm_thumb_mov_rlo_i8(as, reg_dest, i32);
353
354
355
356
357
358
359
    } else if (UNSIGNED_FIT16(i32)) {
        asm_thumb_mov_reg_i16(as, OP_MOVW, reg_dest, i32);
    } else {
        asm_thumb_mov_reg_i32(as, reg_dest, i32);
    }
}

Damien's avatar
Damien committed
360
361
362
363
364
365
366
#define OP_STR_TO_SP_OFFSET(rlo_dest, word_offset) (0x9000 | ((rlo_dest) << 8) | ((word_offset) & 0x00ff))
#define OP_LDR_FROM_SP_OFFSET(rlo_dest, word_offset) (0x9800 | ((rlo_dest) << 8) | ((word_offset) & 0x00ff))

void asm_thumb_mov_local_reg(asm_thumb_t *as, int local_num, uint rlo_src) {
    assert(rlo_src < REG_R8);
    int word_offset = as->num_locals - local_num - 1;
    assert(as->pass < ASM_THUMB_PASS_3 || word_offset >= 0);
367
    asm_thumb_op16(as, OP_STR_TO_SP_OFFSET(rlo_src, word_offset));
Damien's avatar
Damien committed
368
369
370
371
372
373
}

void asm_thumb_mov_reg_local(asm_thumb_t *as, uint rlo_dest, int local_num) {
    assert(rlo_dest < REG_R8);
    int word_offset = as->num_locals - local_num - 1;
    assert(as->pass < ASM_THUMB_PASS_3 || word_offset >= 0);
374
    asm_thumb_op16(as, OP_LDR_FROM_SP_OFFSET(rlo_dest, word_offset));
Damien's avatar
Damien committed
375
376
}

Damien's avatar
Damien committed
377
378
379
380
381
382
#define OP_ADD_REG_SP_OFFSET(rlo_dest, word_offset) (0xa800 | ((rlo_dest) << 8) | ((word_offset) & 0x00ff))

void asm_thumb_mov_reg_local_addr(asm_thumb_t *as, uint rlo_dest, int local_num) {
    assert(rlo_dest < REG_R8);
    int word_offset = as->num_locals - local_num - 1;
    assert(as->pass < ASM_THUMB_PASS_3 || word_offset >= 0);
383
    asm_thumb_op16(as, OP_ADD_REG_SP_OFFSET(rlo_dest, word_offset));
Damien's avatar
Damien committed
384
385
386
387
388
389
}

// this could be wrong, because it should have a range of +/- 16MiB...
#define OP_BW_HI(byte_offset) (0xf000 | (((byte_offset) >> 12) & 0x07ff))
#define OP_BW_LO(byte_offset) (0xb800 | (((byte_offset) >> 1) & 0x07ff))

390
void asm_thumb_b_label(asm_thumb_t *as, uint label) {
391
392
393
394
395
396
397
    int dest = get_label_dest(as, label);
    int rel = dest - as->code_offset;
    rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
    if (dest >= 0 && rel <= -4) {
        // is a backwards jump, so we know the size of the jump on the first pass
        // calculate rel assuming 12 bit relative jump
        if (SIGNED_FIT12(rel)) {
398
            asm_thumb_op16(as, OP_B_N(rel));
Damien's avatar
Damien committed
399
        } else {
400
            goto large_jump;
Damien's avatar
Damien committed
401
        }
402
403
404
    } else {
        // is a forwards jump, so need to assume it's large
        large_jump:
405
        asm_thumb_op32(as, OP_BW_HI(rel), OP_BW_LO(rel));
Damien's avatar
Damien committed
406
407
408
409
    }
}

// all these bit arithmetics need coverage testing!
410
411
#define OP_BCC_W_HI(cond, byte_offset) (0xf000 | ((cond) << 6) | (((byte_offset) >> 10) & 0x0400) | (((byte_offset) >> 14) & 0x003f))
#define OP_BCC_W_LO(byte_offset) (0x8000 | ((byte_offset) & 0x2000) | (((byte_offset) >> 1) & 0x0fff))
Damien's avatar
Damien committed
412

413
void asm_thumb_bcc_label(asm_thumb_t *as, int cond, uint label) {
414
415
416
417
418
    int dest = get_label_dest(as, label);
    int rel = dest - as->code_offset;
    rel -= 4; // account for instruction prefetch, PC is 4 bytes ahead of this instruction
    if (dest >= 0 && rel <= -4) {
        // is a backwards jump, so we know the size of the jump on the first pass
419
        // calculate rel assuming 9 bit relative jump
420
        if (SIGNED_FIT9(rel)) {
421
            asm_thumb_op16(as, OP_BCC_N(cond, rel));
Damien's avatar
Damien committed
422
        } else {
423
            goto large_jump;
Damien's avatar
Damien committed
424
        }
425
426
427
    } else {
        // is a forwards jump, so need to assume it's large
        large_jump:
428
        asm_thumb_op32(as, OP_BCC_W_HI(cond, rel), OP_BCC_W_LO(rel));
Damien's avatar
Damien committed
429
430
431
432
433
434
435
436
437
438
439
    }
}

#define OP_BLX(reg) (0x4780 | ((reg) << 3))
#define OP_SVC(arg) (0xdf00 | (arg))

void asm_thumb_bl_ind(asm_thumb_t *as, void *fun_ptr, uint fun_id, uint reg_temp) {
    /* TODO make this use less bytes
    uint rlo_base = REG_R3;
    uint rlo_dest = REG_R7;
    uint word_offset = 4;
440
441
442
    asm_thumb_op16(as, 0x0000);
    asm_thumb_op16(as, 0x6800 | (word_offset << 6) | (rlo_base << 3) | rlo_dest); // ldr rlo_dest, [rlo_base, #offset]
    asm_thumb_op16(as, 0x4780 | (REG_R9 << 3)); // blx reg
Damien's avatar
Damien committed
443
444
445
446
447
448
    */

    if (0) {
        // load ptr to function into register using immediate, then branch
        // not relocatable
        asm_thumb_mov_reg_i32(as, reg_temp, (machine_uint_t)fun_ptr);
449
        asm_thumb_op16(as, OP_BLX(reg_temp));
Damien's avatar
Damien committed
450
    } else if (1) {
451
452
        asm_thumb_op16(as, OP_FORMAT_9_10(ASM_THUMB_FORMAT_9_LDR | ASM_THUMB_FORMAT_9_WORD_TRANSFER, reg_temp, REG_R7, fun_id));
        asm_thumb_op16(as, OP_BLX(reg_temp));
Damien's avatar
Damien committed
453
454
    } else {
        // use SVC
455
        asm_thumb_op16(as, OP_SVC(fun_id));
Damien's avatar
Damien committed
456
457
    }
}
458
459

#endif // MICROPY_EMIT_THUMB || MICROPY_EMIT_INLINE_THUMB