Line data Source code
1 : /*
2 : ** DynASM x86 encoding engine.
3 : ** Copyright (C) 2005-2023 Mike Pall. All rights reserved.
4 : ** Released under the MIT license. See dynasm.lua for full copyright notice.
5 : */
6 :
7 : #include <stddef.h>
8 : #include <stdarg.h>
9 : #include <string.h>
10 : #include <stdlib.h>
11 :
12 : #define DASM_ARCH "x86"
13 :
14 : #ifndef DASM_EXTERN
15 0 : #define DASM_EXTERN(a,b,c,d) 0
16 : #endif
17 :
18 : /* Action definitions. DASM_STOP must be 255. */
19 : enum {
20 : DASM_DISP = 233,
21 : DASM_IMM_S, DASM_IMM_B, DASM_IMM_W, DASM_IMM_D, DASM_IMM_WB, DASM_IMM_DB,
22 : DASM_VREG, DASM_SPACE, DASM_SETLABEL, DASM_REL_A, DASM_REL_LG, DASM_REL_PC,
23 : DASM_IMM_LG, DASM_IMM_PC, DASM_LABEL_LG, DASM_LABEL_PC, DASM_ALIGN,
24 : DASM_EXTERN, DASM_ESC, DASM_MARK, DASM_SECTION, DASM_STOP
25 : };
26 :
27 : /* Maximum number of section buffer positions for a single dasm_put() call. */
28 3 : #define DASM_MAXSECPOS 25
29 :
30 : /* DynASM encoder status codes. Action list offset or number are or'ed in. */
31 3 : #define DASM_S_OK 0x00000000
32 : #define DASM_S_NOMEM 0x01000000
33 0 : #define DASM_S_PHASE 0x02000000
34 : #define DASM_S_MATCH_SEC 0x03000000
35 : #define DASM_S_RANGE_I 0x11000000
36 : #define DASM_S_RANGE_SEC 0x12000000
37 : #define DASM_S_RANGE_LG 0x13000000
38 : #define DASM_S_RANGE_PC 0x14000000
39 : #define DASM_S_RANGE_VREG 0x15000000
40 : #define DASM_S_UNDEF_L 0x21000000
41 : #define DASM_S_UNDEF_PC 0x22000000
42 :
43 : /* Macros to convert positions (8 bit section + 24 bit index). */
44 : #define DASM_POS2IDX(pos) ((pos)&0x00ffffff)
45 0 : #define DASM_POS2BIAS(pos) ((pos)&0xff000000)
46 3 : #define DASM_SEC2POS(sec) ((sec)<<24)
47 0 : #define DASM_POS2SEC(pos) ((pos)>>24)
48 0 : #define DASM_POS2PTR(D, pos) (D->sections[DASM_POS2SEC(pos)].rbuf + (pos))
49 :
50 : /* Action list type. */
51 : typedef const unsigned char *dasm_ActList;
52 :
53 : /* Per-section structure. */
54 : typedef struct dasm_Section {
55 : int *rbuf; /* Biased buffer pointer (negative section bias). */
56 : int *buf; /* True buffer pointer. */
57 : size_t bsize; /* Buffer size in bytes. */
58 : int pos; /* Biased buffer position. */
59 : int epos; /* End of biased buffer position - max single put. */
60 : int ofs; /* Byte offset into section. */
61 : } dasm_Section;
62 :
63 : /* Core structure holding the DynASM encoding state. */
64 : struct dasm_State {
65 : size_t psize; /* Allocated size of this structure. */
66 : dasm_ActList actionlist; /* Current actionlist pointer. */
67 : int *lglabels; /* Local/global chain/pos ptrs. */
68 : size_t lgsize;
69 : int *pclabels; /* PC label chains/pos ptrs. */
70 : size_t pcsize;
71 : void **globals; /* Array of globals. */
72 : dasm_Section *section; /* Pointer to active section. */
73 : size_t codesize; /* Total size of all code sections. */
74 : int maxsection; /* 0 <= sectionidx < maxsection. */
75 : int status; /* Status code. */
76 : dasm_Section sections[1]; /* All sections. Alloc-extended. */
77 : };
78 :
79 : /* The size of the core structure depends on the max. number of sections. */
80 6 : #define DASM_PSZ(ms) (sizeof(dasm_State)+(ms-1)*sizeof(dasm_Section))
81 :
82 : #ifndef FD_DASM_HEADER_ONLY
83 : #define FD_DASM_HEADER_ONLY 0
84 : #endif
85 :
86 : #if !FD_DASM_HEADER_ONLY
87 :
88 : /* Initialize DynASM state. */
89 : void dasm_init(Dst_DECL, int maxsection)
90 0 : {
91 0 : dasm_State *D;
92 0 : size_t psz = 0;
93 0 : Dst_REF = NULL;
94 0 : DASM_M_GROW(Dst, struct dasm_State, Dst_REF, psz, DASM_PSZ(maxsection));
95 0 : D = Dst_REF;
96 0 : D->psize = psz;
97 0 : D->lglabels = NULL;
98 0 : D->lgsize = 0;
99 0 : D->pclabels = NULL;
100 0 : D->pcsize = 0;
101 0 : D->globals = NULL;
102 0 : D->maxsection = maxsection;
103 0 : memset((void *)D->sections, 0, maxsection * sizeof(dasm_Section));
104 0 : }
105 :
106 : /* Free DynASM state. */
107 : void dasm_free(Dst_DECL)
108 0 : {
109 0 : dasm_State *D = Dst_REF;
110 0 : int i;
111 0 : for (i = 0; i < D->maxsection; i++)
112 0 : if (D->sections[i].buf)
113 0 : DASM_M_FREE(Dst, D->sections[i].buf, D->sections[i].bsize);
114 0 : if (D->pclabels) DASM_M_FREE(Dst, D->pclabels, D->pcsize);
115 0 : if (D->lglabels) DASM_M_FREE(Dst, D->lglabels, D->lgsize);
116 0 : DASM_M_FREE(Dst, D, D->psize);
117 0 : }
118 :
119 : /* Setup global label array. Must be called before dasm_setup(). */
120 : void dasm_setupglobal(Dst_DECL, void **gl, unsigned int maxgl)
121 0 : {
122 0 : dasm_State *D = Dst_REF;
123 0 : D->globals = gl;
124 0 : DASM_M_GROW(Dst, int, D->lglabels, D->lgsize, (10+maxgl)*sizeof(int));
125 0 : }
126 :
127 : /* Grow PC label array. Can be called after dasm_setup(), too. */
128 : void dasm_growpc(Dst_DECL, unsigned int maxpc)
129 0 : {
130 0 : dasm_State *D = Dst_REF;
131 0 : size_t osz = D->pcsize;
132 0 : DASM_M_GROW(Dst, int, D->pclabels, D->pcsize, maxpc*sizeof(int));
133 0 : memset((void *)(((unsigned char *)D->pclabels)+osz), 0, D->pcsize-osz);
134 0 : }
135 :
136 : /* Setup encoder. */
137 : void dasm_setup(Dst_DECL, const void *actionlist)
138 3 : {
139 3 : dasm_State *D = Dst_REF;
140 3 : int i;
141 3 : D->actionlist = (dasm_ActList)actionlist;
142 3 : D->status = DASM_S_OK;
143 3 : D->section = &D->sections[0];
144 3 : memset((void *)D->lglabels, 0, D->lgsize);
145 3 : if (D->pclabels) memset((void *)D->pclabels, 0, D->pcsize);
146 6 : for (i = 0; i < D->maxsection; i++) {
147 3 : D->sections[i].pos = DASM_SEC2POS(i);
148 3 : D->sections[i].rbuf = D->sections[i].buf - D->sections[i].pos;
149 3 : D->sections[i].ofs = 0;
150 3 : }
151 3 : }
152 :
153 :
154 : #ifdef DASM_CHECKS
155 : #define CK(x, st) \
156 : do { if (!(x)) { \
157 : D->status = DASM_S_##st|(int)(p-D->actionlist-1); return; } } while (0)
158 : #define CKPL(kind, st) \
159 : do { if ((size_t)((char *)pl-(char *)D->kind##labels) >= D->kind##size) { \
160 : D->status=DASM_S_RANGE_##st|(int)(p-D->actionlist-1); return; } } while (0)
161 : #else
162 0 : #define CK(x, st) ((void)0)
163 0 : #define CKPL(kind, st) ((void)0)
164 : #endif
165 :
166 : /* Pass 1: Store actions and args, link branches/labels, estimate offsets. */
167 : void dasm_put(Dst_DECL, int start, ...)
168 0 : {
169 0 : va_list ap;
170 0 : dasm_State *D = Dst_REF;
171 0 : dasm_ActList p = D->actionlist + start;
172 0 : dasm_Section *sec = D->section;
173 0 : int pos = sec->pos, ofs = sec->ofs, mrm = -1;
174 0 : int *b;
175 :
176 0 : if (pos >= sec->epos) {
177 0 : DASM_M_GROW(Dst, int, sec->buf, sec->bsize,
178 0 : sec->bsize + 2*DASM_MAXSECPOS*sizeof(int));
179 0 : sec->rbuf = sec->buf - DASM_POS2BIAS(pos);
180 0 : sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos);
181 0 : }
182 :
183 0 : b = sec->rbuf;
184 0 : b[pos++] = start;
185 :
186 0 : va_start(ap, start);
187 0 : while (1) {
188 0 : int action = *p++;
189 0 : if (action < DASM_DISP) {
190 0 : ofs++;
191 0 : } else if (action <= DASM_REL_A) {
192 0 : int n = va_arg(ap, int);
193 0 : b[pos++] = n;
194 0 : switch (action) {
195 0 : case DASM_DISP:
196 0 : if (n == 0) { if (mrm < 0) mrm = p[-2]; if ((mrm&7) != 5) break; }
197 : /* fallthrough */
198 0 : case DASM_IMM_DB: if (((n+128)&-256) == 0) goto ob; /* fallthrough */
199 0 : case DASM_REL_A: /* Assumes ptrdiff_t is int. !x64 */
200 0 : case DASM_IMM_D: ofs += 4; break;
201 0 : case DASM_IMM_S: CK(((n+128)&-256) == 0, RANGE_I); goto ob;
202 0 : case DASM_IMM_B: CK((n&-256) == 0, RANGE_I); ob: ofs++; break;
203 0 : case DASM_IMM_WB: if (((n+128)&-256) == 0) goto ob; /* fallthrough */
204 0 : case DASM_IMM_W: CK((n&-65536) == 0, RANGE_I); ofs += 2; break;
205 0 : case DASM_SPACE: p++; ofs += n; break;
206 0 : case DASM_SETLABEL: b[pos-2] = -0x40000000; break; /* Neg. label ofs. */
207 0 : case DASM_VREG: CK((n&-16) == 0 && (n != 4 || (*p>>5) != 2), RANGE_VREG);
208 0 : if (*p < 0x40 && p[1] == DASM_DISP) mrm = n;
209 0 : if (*p < 0x20 && (n&7) == 4) ofs++;
210 0 : switch ((*p++ >> 3) & 3) {
211 0 : case 3: n |= b[pos-3]; /* fallthrough */
212 0 : case 2: n |= b[pos-2]; /* fallthrough */
213 0 : case 1: if (n <= 7) { b[pos-1] |= 0x10; ofs--; }
214 0 : }
215 0 : continue;
216 0 : }
217 0 : mrm = -1;
218 0 : } else {
219 0 : int *pl, n;
220 0 : switch (action) {
221 0 : case DASM_REL_LG:
222 0 : case DASM_IMM_LG:
223 0 : n = *p++; pl = D->lglabels + n;
224 : /* Bkwd rel or global. */
225 0 : if (n <= 246) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; }
226 0 : pl -= 246; n = *pl;
227 0 : if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */
228 0 : goto linkrel;
229 0 : case DASM_REL_PC:
230 0 : case DASM_IMM_PC: pl = D->pclabels + va_arg(ap, int); CKPL(pc, PC);
231 0 : putrel:
232 0 : n = *pl;
233 0 : if (n < 0) { /* Label exists. Get label pos and store it. */
234 0 : b[pos] = -n;
235 0 : } else {
236 0 : linkrel:
237 0 : b[pos] = n; /* Else link to rel chain, anchored at label. */
238 0 : *pl = pos;
239 0 : }
240 0 : pos++;
241 0 : ofs += 4; /* Maximum offset needed. */
242 0 : if (action == DASM_REL_LG || action == DASM_REL_PC) {
243 0 : b[pos++] = ofs; /* Store pass1 offset estimate. */
244 0 : } else if (sizeof(ptrdiff_t) == 8) {
245 0 : ofs += 4;
246 0 : }
247 0 : break;
248 0 : case DASM_LABEL_LG: pl = D->lglabels + *p++; CKPL(lg, LG); goto putlabel;
249 0 : case DASM_LABEL_PC: pl = D->pclabels + va_arg(ap, int); CKPL(pc, PC);
250 0 : putlabel:
251 0 : n = *pl; /* n > 0: Collapse rel chain and replace with label pos. */
252 0 : while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos; }
253 0 : *pl = -pos; /* Label exists now. */
254 0 : b[pos++] = ofs; /* Store pass1 offset estimate. */
255 0 : break;
256 0 : case DASM_ALIGN:
257 0 : ofs += *p++; /* Maximum alignment needed (arg is 2**n-1). */
258 0 : b[pos++] = ofs; /* Store pass1 offset estimate. */
259 0 : break;
260 0 : case DASM_EXTERN: p += 2; ofs += 4; break;
261 0 : case DASM_ESC: p++; ofs++; break;
262 0 : case DASM_MARK: mrm = p[-2]; break;
263 0 : case DASM_SECTION:
264 0 : n = *p; CK(n < D->maxsection, RANGE_SEC); D->section = &D->sections[n];
265 0 : case DASM_STOP: goto stop;
266 0 : }
267 0 : }
268 0 : }
269 0 : stop:
270 0 : va_end(ap);
271 0 : sec->pos = pos;
272 0 : sec->ofs = ofs;
273 0 : }
274 : #undef CK
275 :
276 : /* Pass 2: Link sections, shrink branches/aligns, fix label offsets. */
277 : int dasm_link(Dst_DECL, size_t *szp)
278 0 : {
279 0 : dasm_State *D = Dst_REF;
280 0 : int secnum;
281 0 : int ofs = 0;
282 :
283 : #ifdef DASM_CHECKS
284 : *szp = 0;
285 : if (D->status != DASM_S_OK) return D->status;
286 : {
287 : int pc;
288 : for (pc = 0; pc*sizeof(int) < D->pcsize; pc++)
289 : if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc;
290 : }
291 : #endif
292 :
293 0 : { /* Handle globals not defined in this translation unit. */
294 0 : int idx;
295 0 : for (idx = 10; idx*sizeof(int) < D->lgsize; idx++) {
296 0 : int n = D->lglabels[idx];
297 : /* Undefined label: Collapse rel chain and replace with marker (< 0). */
298 0 : while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; }
299 0 : }
300 0 : }
301 :
302 : /* Combine all code sections. No support for data sections (yet). */
303 0 : for (secnum = 0; secnum < D->maxsection; secnum++) {
304 0 : dasm_Section *sec = D->sections + secnum;
305 0 : int *b = sec->rbuf;
306 0 : int pos = DASM_SEC2POS(secnum);
307 0 : int lastpos = sec->pos;
308 :
309 0 : while (pos != lastpos) {
310 0 : dasm_ActList p = D->actionlist + b[pos++];
311 0 : int op = 0;
312 0 : while (1) {
313 0 : int action = *p++;
314 0 : switch (action) {
315 0 : case DASM_REL_LG: p++;
316 : /* fallthrough */
317 0 : case DASM_REL_PC: {
318 0 : int shrink = op == 0xe9 ? 3 : ((op&0xf0) == 0x80 ? 4 : 0);
319 0 : if (shrink) { /* Shrinkable branch opcode? */
320 0 : int lofs, lpos = b[pos];
321 0 : if (lpos < 0) goto noshrink; /* Ext global? */
322 0 : lofs = *DASM_POS2PTR(D, lpos);
323 0 : if (lpos > pos) { /* Fwd label: add cumulative section offsets. */
324 0 : int i;
325 0 : for (i = secnum; i < DASM_POS2SEC(lpos); i++)
326 0 : lofs += D->sections[i].ofs;
327 0 : } else {
328 0 : lofs -= ofs; /* Bkwd label: unfix offset. */
329 0 : }
330 0 : lofs -= b[pos+1]; /* Short branch ok? */
331 0 : if (lofs >= -128-shrink && lofs <= 127) ofs -= shrink; /* Yes. */
332 0 : else { noshrink: shrink = 0; } /* No, cannot shrink op. */
333 0 : }
334 0 : b[pos+1] = shrink;
335 0 : pos += 2;
336 0 : break;
337 0 : }
338 : /* fallthrough */
339 0 : case DASM_SPACE: case DASM_IMM_LG: case DASM_VREG: p++;
340 : /* fallthrough */
341 0 : case DASM_DISP: case DASM_IMM_S: case DASM_IMM_B: case DASM_IMM_W:
342 0 : case DASM_IMM_D: case DASM_IMM_WB: case DASM_IMM_DB:
343 0 : case DASM_SETLABEL: case DASM_REL_A: case DASM_IMM_PC: pos++; break;
344 0 : case DASM_LABEL_LG: p++;
345 : /* fallthrough */
346 0 : case DASM_LABEL_PC: b[pos++] += ofs; break; /* Fix label offset. */
347 0 : case DASM_ALIGN: ofs -= (b[pos++]+ofs)&*p++; break; /* Adjust ofs. */
348 0 : case DASM_EXTERN: p += 2; break;
349 0 : case DASM_ESC: op = *p++; break;
350 0 : case DASM_MARK: break;
351 0 : case DASM_SECTION: case DASM_STOP: goto stop;
352 0 : default: op = action; break;
353 0 : }
354 0 : }
355 0 : stop: (void)0;
356 0 : }
357 0 : ofs += sec->ofs; /* Next section starts right after current section. */
358 0 : }
359 :
360 0 : D->codesize = ofs; /* Total size of all code sections */
361 0 : *szp = ofs;
362 0 : return DASM_S_OK;
363 0 : }
364 :
365 0 : #define dasmb(x) *cp++ = (unsigned char)(x)
366 : #ifndef DASM_ALIGNED_WRITES
367 : #define dasmw(x) \
368 0 : do { *((unsigned short *)cp) = (unsigned short)(x); cp+=2; } while (0)
369 : #define dasmd(x) \
370 0 : do { *((unsigned int *)cp) = (unsigned int)(x); cp+=4; } while (0)
371 : #define dasmq(x) \
372 0 : do { *((unsigned long long *)cp) = (unsigned long long)(x); cp+=8; } while (0)
373 : #else
374 : #define dasmw(x) do { dasmb(x); dasmb((x)>>8); } while (0)
375 : #define dasmd(x) do { dasmw(x); dasmw((x)>>16); } while (0)
376 : #define dasmq(x) do { dasmd(x); dasmd((x)>>32); } while (0)
377 : #endif
378 : static unsigned char *dasma_(unsigned char *cp, ptrdiff_t x)
379 0 : {
380 0 : if (sizeof(ptrdiff_t) == 8)
381 0 : dasmq((unsigned long long)x);
382 0 : else
383 0 : dasmd((unsigned int)x);
384 0 : return cp;
385 0 : }
386 0 : #define dasma(x) (cp = dasma_(cp, (x)))
387 :
388 : /* Pass 3: Encode sections. */
389 : int dasm_encode(Dst_DECL, void *buffer)
390 0 : {
391 0 : dasm_State *D = Dst_REF;
392 0 : unsigned char *base = (unsigned char *)buffer;
393 0 : unsigned char *cp = base;
394 0 : int secnum;
395 :
396 : /* Encode all code sections. No support for data sections (yet). */
397 0 : for (secnum = 0; secnum < D->maxsection; secnum++) {
398 0 : dasm_Section *sec = D->sections + secnum;
399 0 : int *b = sec->buf;
400 0 : int *endb = sec->rbuf + sec->pos;
401 :
402 0 : while (b != endb) {
403 0 : dasm_ActList p = D->actionlist + *b++;
404 0 : unsigned char *mark = NULL;
405 0 : while (1) {
406 0 : int action = *p++;
407 0 : int n = (action >= DASM_DISP && action <= DASM_ALIGN) ? *b++ : 0;
408 0 : switch (action) {
409 0 : case DASM_DISP: if (!mark) mark = cp; {
410 0 : unsigned char *mm = mark;
411 0 : if (*p != DASM_IMM_DB && *p != DASM_IMM_WB) mark = NULL;
412 0 : if (n == 0) { int mrm = mm[-1]&7; if (mrm == 4) mrm = mm[0]&7;
413 0 : if (mrm != 5) { mm[-1] -= 0x80; break; } }
414 0 : if (((n+128) & -256) != 0) goto wd; else mm[-1] -= 0x40;
415 0 : }
416 : /* fallthrough */
417 0 : case DASM_IMM_S: case DASM_IMM_B: wb: dasmb(n); break;
418 0 : case DASM_IMM_DB: if (((n+128)&-256) == 0) {
419 0 : db: if (!mark) mark = cp; mark[-2] += 2; mark = NULL; goto wb;
420 0 : } else mark = NULL;
421 : /* fallthrough */
422 0 : case DASM_IMM_D: wd: dasmd(n); break;
423 0 : case DASM_IMM_WB: if (((n+128)&-256) == 0) goto db; else mark = NULL;
424 : /* fallthrough */
425 0 : case DASM_IMM_W: dasmw(n); break;
426 0 : case DASM_VREG: {
427 0 : int t = *p++;
428 0 : unsigned char *ex = cp - (t&7);
429 0 : if ((n & 8) && t < 0xa0) {
430 0 : if (*ex & 0x80) ex[1] ^= 0x20 << (t>>6); else *ex ^= 1 << (t>>6);
431 0 : n &= 7;
432 0 : } else if (n & 0x10) {
433 0 : if (*ex & 0x80) {
434 0 : *ex = 0xc5; ex[1] = (ex[1] & 0x80) | ex[2]; ex += 2;
435 0 : }
436 0 : while (++ex < cp) ex[-1] = *ex;
437 0 : if (mark) mark--;
438 0 : cp--;
439 0 : n &= 7;
440 0 : }
441 0 : if (t >= 0xc0) n <<= 4;
442 0 : else if (t >= 0x40) n <<= 3;
443 0 : else if (n == 4 && t < 0x20) { cp[-1] ^= n; *cp++ = 0x20; }
444 0 : cp[-1] ^= n;
445 0 : break;
446 0 : }
447 0 : case DASM_REL_LG: p++; if (n >= 0) goto rel_pc;
448 0 : b++; n = (int)(ptrdiff_t)D->globals[-n-10];
449 : /* fallthrough */
450 0 : case DASM_REL_A: rel_a:
451 0 : n -= (unsigned int)(ptrdiff_t)(cp+4); goto wd; /* !x64 */
452 0 : case DASM_REL_PC: rel_pc: {
453 0 : int shrink = *b++;
454 0 : int *pb = DASM_POS2PTR(D, n); if (*pb < 0) { n = pb[1]; goto rel_a; }
455 0 : n = *pb - ((int)(cp-base) + 4-shrink);
456 0 : if (shrink == 0) goto wd;
457 0 : if (shrink == 4) { cp--; cp[-1] = *cp-0x10; } else cp[-1] = 0xeb;
458 0 : goto wb;
459 0 : }
460 0 : case DASM_IMM_LG:
461 0 : p++;
462 0 : if (n < 0) { dasma((ptrdiff_t)D->globals[-n-10]); break; }
463 : /* fallthrough */
464 0 : case DASM_IMM_PC: {
465 0 : int *pb = DASM_POS2PTR(D, n);
466 0 : dasma(*pb < 0 ? (ptrdiff_t)pb[1] : (*pb + (ptrdiff_t)base));
467 0 : break;
468 0 : }
469 0 : case DASM_LABEL_LG: {
470 0 : int idx = *p++;
471 0 : if (idx >= 10)
472 0 : D->globals[idx-10] = (void *)(base + (*p == DASM_SETLABEL ? *b : n));
473 0 : break;
474 0 : }
475 0 : case DASM_LABEL_PC: case DASM_SETLABEL: break;
476 0 : case DASM_SPACE: { int fill = *p++; while (n--) *cp++ = fill; break; }
477 0 : case DASM_ALIGN:
478 0 : n = *p++;
479 0 : while (((cp-base) & n)) *cp++ = 0x90; /* nop */
480 0 : break;
481 0 : case DASM_EXTERN: n = DASM_EXTERN(Dst, cp, p[1], *p); p += 2; goto wd;
482 0 : case DASM_MARK: mark = cp; break;
483 0 : case DASM_ESC: action = *p++;
484 : /* fallthrough */
485 0 : default: *cp++ = action; break;
486 0 : case DASM_SECTION: case DASM_STOP: goto stop;
487 0 : }
488 0 : }
489 0 : stop: (void)0;
490 0 : }
491 0 : }
492 :
493 0 : if (base + D->codesize != cp) /* Check for phase errors. */
494 0 : return DASM_S_PHASE;
495 0 : return DASM_S_OK;
496 0 : }
497 :
498 : /* Get PC label offset. */
499 : int dasm_getpclabel(Dst_DECL, unsigned int pc)
500 0 : {
501 0 : dasm_State *D = Dst_REF;
502 0 : if (pc*sizeof(int) < D->pcsize) {
503 0 : int pos = D->pclabels[pc];
504 0 : if (pos < 0) return *DASM_POS2PTR(D, -pos);
505 0 : if (pos > 0) return -1; /* Undefined. */
506 0 : }
507 0 : return -2; /* Unused or out of range. */
508 0 : }
509 :
510 : #ifdef DASM_CHECKS
511 : /* Optional sanity checker to call between isolated encoding steps. */
512 : int dasm_checkstep(Dst_DECL, int secmatch)
513 : {
514 : dasm_State *D = Dst_REF;
515 : if (D->status == DASM_S_OK) {
516 : int i;
517 : for (i = 1; i <= 9; i++) {
518 : if (D->lglabels[i] > 0) { D->status = DASM_S_UNDEF_L|i; break; }
519 : D->lglabels[i] = 0;
520 : }
521 : }
522 : if (D->status == DASM_S_OK && secmatch >= 0 &&
523 : D->section != &D->sections[secmatch])
524 : D->status = DASM_S_MATCH_SEC|(int)(D->section-D->sections);
525 : return D->status;
526 : }
527 : #endif
528 :
529 : #endif /* !FD_DASM_HEADER_ONLY */
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