1 /* Interface definition for configurable Xtensa ISA support.
2    Copyright (C) 2003-2016 Free Software Foundation, Inc.
3 
4    This file is part of BFD, the Binary File Descriptor library.
5 
6    This program is free software; you can redistribute it and/or modify
7    it under the terms of the GNU General Public License as published by
8    the Free Software Foundation; either version 3 of the License, or
9    (at your option) any later version.
10 
11    This program 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
14    GNU General Public License for more details.
15 
16    You should have received a copy of the GNU General Public License
17    along with this program; if not, write to the Free Software
18    Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,
19    USA.  */
20 
21 #ifndef XTENSA_LIBISA_H
22 #define XTENSA_LIBISA_H
23 
24 #ifdef __cplusplus
25 extern "C" {
26 #endif
27 
28 /* Version number: This is intended to help support code that works with
29    versions of this library from multiple Xtensa releases.  */
30 
31 #define XTENSA_ISA_VERSION 7000
32 
33 #ifndef uint32
34 #define uint32 unsigned int
35 #endif
36 
37 /* This file defines the interface to the Xtensa ISA library.  This
38    library contains most of the ISA-specific information for a
39    particular Xtensa processor.  For example, the set of valid
40    instructions, their opcode encodings and operand fields are all
41    included here.
42 
43    This interface basically defines a number of abstract data types.
44 
45    . an instruction buffer - for holding the raw instruction bits
46    . ISA info - information about the ISA as a whole
47    . instruction formats - instruction size and slot structure
48    . opcodes - information about individual instructions
49    . operands - information about register and immediate instruction operands
50    . stateOperands - information about processor state instruction operands
51    . interfaceOperands - information about interface instruction operands
52    . register files - register file information
53    . processor states - internal processor state information
54    . system registers - "special registers" and "user registers"
55    . interfaces - TIE interfaces that are external to the processor
56    . functional units - TIE shared functions
57 
58    The interface defines a set of functions to access each data type.
59    With the exception of the instruction buffer, the internal
60    representations of the data structures are hidden.  All accesses must
61    be made through the functions defined here.  */
62 
63 typedef struct xtensa_isa_opaque { int unused; } *xtensa_isa;
64 
65 
66 /* Most of the Xtensa ISA entities (e.g., opcodes, regfiles, etc.) are
67    represented here using sequential integers beginning with 0.  The
68    specific values are only fixed for a particular instantiation of an
69    xtensa_isa structure, so these values should only be used
70    internally.  */
71 
72 typedef int xtensa_opcode;
73 typedef int xtensa_format;
74 typedef int xtensa_regfile;
75 typedef int xtensa_state;
76 typedef int xtensa_sysreg;
77 typedef int xtensa_interface;
78 typedef int xtensa_funcUnit;
79 
80 
81 /* Define a unique value for undefined items.  */
82 
83 #define XTENSA_UNDEFINED -1
84 
85 
86 /* Overview of using this interface to decode/encode instructions:
87 
88    Each Xtensa instruction is associated with a particular instruction
89    format, where the format defines a fixed number of slots for
90    operations.  The formats for the core Xtensa ISA have only one slot,
91    but FLIX instructions may have multiple slots.  Within each slot,
92    there is a single opcode and some number of associated operands.
93 
94    The encoding and decoding functions operate on instruction buffers,
95    not on the raw bytes of the instructions.  The same instruction
96    buffer data structure is used for both entire instructions and
97    individual slots in those instructions -- the contents of a slot need
98    to be extracted from or inserted into the buffer for the instruction
99    as a whole.
100 
101    Decoding an instruction involves first finding the format, which
102    identifies the number of slots, and then decoding each slot
103    separately.  A slot is decoded by finding the opcode and then using
104    the opcode to determine how many operands there are.  For example:
105 
106    xtensa_insnbuf_from_chars
107    xtensa_format_decode
108    for each slot {
109      xtensa_format_get_slot
110      xtensa_opcode_decode
111      for each operand {
112        xtensa_operand_get_field
113        xtensa_operand_decode
114      }
115    }
116 
117    Encoding an instruction is roughly the same procedure in reverse:
118 
119    xtensa_format_encode
120    for each slot {
121      xtensa_opcode_encode
122      for each operand {
123        xtensa_operand_encode
124        xtensa_operand_set_field
125      }
126      xtensa_format_set_slot
127    }
128    xtensa_insnbuf_to_chars
129 */
130 
131 
132 /* Error handling.  */
133 
134 /* Error codes.  The code for the most recent error condition can be
135    retrieved with the "errno" function.  For any result other than
136    xtensa_isa_ok, an error message containing additional information
137    about the problem can be retrieved using the "error_msg" function.
138    The error messages are stored in an internal buffer, which should
139    not be freed and may be overwritten by subsequent operations.  */
140 
141 typedef enum xtensa_isa_status_enum
142 {
143   xtensa_isa_ok = 0,
144   xtensa_isa_bad_format,
145   xtensa_isa_bad_slot,
146   xtensa_isa_bad_opcode,
147   xtensa_isa_bad_operand,
148   xtensa_isa_bad_field,
149   xtensa_isa_bad_iclass,
150   xtensa_isa_bad_regfile,
151   xtensa_isa_bad_sysreg,
152   xtensa_isa_bad_state,
153   xtensa_isa_bad_interface,
154   xtensa_isa_bad_funcUnit,
155   xtensa_isa_wrong_slot,
156   xtensa_isa_no_field,
157   xtensa_isa_out_of_memory,
158   xtensa_isa_buffer_overflow,
159   xtensa_isa_internal_error,
160   xtensa_isa_bad_value
161 } xtensa_isa_status;
162 
163 extern xtensa_isa_status
164 xtensa_isa_errno (xtensa_isa isa);
165 
166 extern char *
167 xtensa_isa_error_msg (xtensa_isa isa);
168 
169 
170 
171 /* Instruction buffers.  */
172 
173 typedef uint32 xtensa_insnbuf_word;
174 typedef xtensa_insnbuf_word *xtensa_insnbuf;
175 
176 
177 /* Get the size in "insnbuf_words" of the xtensa_insnbuf array.  */
178 
179 extern int
180 xtensa_insnbuf_size (xtensa_isa isa);
181 
182 
183 /* Allocate an xtensa_insnbuf of the right size.  */
184 
185 extern xtensa_insnbuf
186 xtensa_insnbuf_alloc (xtensa_isa isa);
187 
188 
189 /* Release an xtensa_insnbuf.  */
190 
191 extern void
192 xtensa_insnbuf_free (xtensa_isa isa, xtensa_insnbuf buf);
193 
194 
195 /* Conversion between raw memory (char arrays) and our internal
196    instruction representation.  This is complicated by the Xtensa ISA's
197    variable instruction lengths.  When converting to chars, the buffer
198    must contain a valid instruction so we know how many bytes to copy;
199    thus, the "to_chars" function returns the number of bytes copied or
200    XTENSA_UNDEFINED on error.  The "from_chars" function first reads the
201    minimal number of bytes required to decode the instruction length and
202    then proceeds to copy the entire instruction into the buffer; if the
203    memory does not contain a valid instruction, it copies the maximum
204    number of bytes required for the longest Xtensa instruction.  The
205    "num_chars" argument may be used to limit the number of bytes that
206    can be read or written.  Otherwise, if "num_chars" is zero, the
207    functions may read or write past the end of the code.  */
208 
209 extern int
210 xtensa_insnbuf_to_chars (xtensa_isa isa, const xtensa_insnbuf insn,
211 			 unsigned char *cp, int num_chars);
212 
213 extern void
214 xtensa_insnbuf_from_chars (xtensa_isa isa, xtensa_insnbuf insn,
215 			   const unsigned char *cp, int num_chars);
216 
217 
218 
219 /* ISA information.  */
220 
221 /* Initialize the ISA information.  */
222 
223 extern xtensa_isa
224 xtensa_isa_init (xtensa_isa_status *errno_p, char **error_msg_p);
225 
226 
227 /* Deallocate an xtensa_isa structure.  */
228 
229 extern void
230 xtensa_isa_free (xtensa_isa isa);
231 
232 
233 /* Get the maximum instruction size in bytes.  */
234 
235 extern int
236 xtensa_isa_maxlength (xtensa_isa isa);
237 
238 
239 /* Decode the length in bytes of an instruction in raw memory (not an
240    insnbuf).  This function reads only the minimal number of bytes
241    required to decode the instruction length.  Returns
242    XTENSA_UNDEFINED on error.  */
243 
244 extern int
245 xtensa_isa_length_from_chars (xtensa_isa isa, const unsigned char *cp);
246 
247 
248 /* Get the number of stages in the processor's pipeline.  The pipeline
249    stage values returned by other functions in this library will range
250    from 0 to N-1, where N is the value returned by this function.
251    Note that the stage numbers used here may not correspond to the
252    actual processor hardware, e.g., the hardware may have additional
253    stages before stage 0.  Returns XTENSA_UNDEFINED on error.  */
254 
255 extern int
256 xtensa_isa_num_pipe_stages (xtensa_isa isa);
257 
258 
259 /* Get the number of various entities that are defined for this processor.  */
260 
261 extern int
262 xtensa_isa_num_formats (xtensa_isa isa);
263 
264 extern int
265 xtensa_isa_num_opcodes (xtensa_isa isa);
266 
267 extern int
268 xtensa_isa_num_regfiles (xtensa_isa isa);
269 
270 extern int
271 xtensa_isa_num_states (xtensa_isa isa);
272 
273 extern int
274 xtensa_isa_num_sysregs (xtensa_isa isa);
275 
276 extern int
277 xtensa_isa_num_interfaces (xtensa_isa isa);
278 
279 extern int
280 xtensa_isa_num_funcUnits (xtensa_isa isa);
281 
282 
283 
284 /* Instruction formats.  */
285 
286 /* Get the name of a format.  Returns null on error.  */
287 
288 extern const char *
289 xtensa_format_name (xtensa_isa isa, xtensa_format fmt);
290 
291 
292 /* Given a format name, return the format number.  Returns
293    XTENSA_UNDEFINED if the name is not a valid format.  */
294 
295 extern xtensa_format
296 xtensa_format_lookup (xtensa_isa isa, const char *fmtname);
297 
298 
299 /* Decode the instruction format from a binary instruction buffer.
300    Returns XTENSA_UNDEFINED if the format is not recognized.  */
301 
302 extern xtensa_format
303 xtensa_format_decode (xtensa_isa isa, const xtensa_insnbuf insn);
304 
305 
306 /* Set the instruction format field(s) in a binary instruction buffer.
307    All the other fields are set to zero.  Returns non-zero on error.  */
308 
309 extern int
310 xtensa_format_encode (xtensa_isa isa, xtensa_format fmt, xtensa_insnbuf insn);
311 
312 
313 /* Find the length (in bytes) of an instruction.  Returns
314    XTENSA_UNDEFINED on error.  */
315 
316 extern int
317 xtensa_format_length (xtensa_isa isa, xtensa_format fmt);
318 
319 
320 /* Get the number of slots in an instruction.  Returns XTENSA_UNDEFINED
321    on error.  */
322 
323 extern int
324 xtensa_format_num_slots (xtensa_isa isa, xtensa_format fmt);
325 
326 
327 /* Get the opcode for a no-op in a particular slot.
328    Returns XTENSA_UNDEFINED on error.  */
329 
330 extern xtensa_opcode
331 xtensa_format_slot_nop_opcode (xtensa_isa isa, xtensa_format fmt, int slot);
332 
333 
334 /* Get the bits for a specified slot out of an insnbuf for the
335    instruction as a whole and put them into an insnbuf for that one
336    slot, and do the opposite to set a slot.  Return non-zero on error.  */
337 
338 extern int
339 xtensa_format_get_slot (xtensa_isa isa, xtensa_format fmt, int slot,
340 			const xtensa_insnbuf insn, xtensa_insnbuf slotbuf);
341 
342 extern int
343 xtensa_format_set_slot (xtensa_isa isa, xtensa_format fmt, int slot,
344 			xtensa_insnbuf insn, const xtensa_insnbuf slotbuf);
345 
346 
347 
348 /* Opcode information.  */
349 
350 /* Translate a mnemonic name to an opcode.  Returns XTENSA_UNDEFINED if
351    the name is not a valid opcode mnemonic.  */
352 
353 extern xtensa_opcode
354 xtensa_opcode_lookup (xtensa_isa isa, const char *opname);
355 
356 
357 /* Decode the opcode for one instruction slot from a binary instruction
358    buffer.  Returns the opcode or XTENSA_UNDEFINED if the opcode is
359    illegal.  */
360 
361 extern xtensa_opcode
362 xtensa_opcode_decode (xtensa_isa isa, xtensa_format fmt, int slot,
363 		      const xtensa_insnbuf slotbuf);
364 
365 
366 /* Set the opcode field(s) for an instruction slot.  All other fields
367    in the slot are set to zero.  Returns non-zero if the opcode cannot
368    be encoded.  */
369 
370 extern int
371 xtensa_opcode_encode (xtensa_isa isa, xtensa_format fmt, int slot,
372 		      xtensa_insnbuf slotbuf, xtensa_opcode opc);
373 
374 
375 /* Get the mnemonic name for an opcode.  Returns null on error.  */
376 
377 extern const char *
378 xtensa_opcode_name (xtensa_isa isa, xtensa_opcode opc);
379 
380 
381 /* Check various properties of opcodes.  These functions return 0 if
382    the condition is false, 1 if the condition is true, and
383    XTENSA_UNDEFINED on error.  The instructions are classified as
384    follows:
385 
386    branch: conditional branch; may fall through to next instruction (B*)
387    jump: unconditional branch (J, JX, RET*, RF*)
388    loop: zero-overhead loop (LOOP*)
389    call: unconditional call; control returns to next instruction (CALL*)
390 
391    For the opcodes that affect control flow in some way, the branch
392    target may be specified by an immediate operand or it may be an
393    address stored in a register.  You can distinguish these by
394    checking if the instruction has a PC-relative immediate
395    operand.  */
396 
397 extern int
398 xtensa_opcode_is_branch (xtensa_isa isa, xtensa_opcode opc);
399 
400 extern int
401 xtensa_opcode_is_jump (xtensa_isa isa, xtensa_opcode opc);
402 
403 extern int
404 xtensa_opcode_is_loop (xtensa_isa isa, xtensa_opcode opc);
405 
406 extern int
407 xtensa_opcode_is_call (xtensa_isa isa, xtensa_opcode opc);
408 
409 
410 /* Find the number of ordinary operands, state operands, and interface
411    operands for an instruction.  These return XTENSA_UNDEFINED on
412    error.  */
413 
414 extern int
415 xtensa_opcode_num_operands (xtensa_isa isa, xtensa_opcode opc);
416 
417 extern int
418 xtensa_opcode_num_stateOperands (xtensa_isa isa, xtensa_opcode opc);
419 
420 extern int
421 xtensa_opcode_num_interfaceOperands (xtensa_isa isa, xtensa_opcode opc);
422 
423 
424 /* Get functional unit usage requirements for an opcode.  Each "use"
425    is identified by a <functional unit, pipeline stage> pair.  The
426    "num_funcUnit_uses" function returns the number of these "uses" or
427    XTENSA_UNDEFINED on error.  The "funcUnit_use" function returns
428    a pointer to a "use" pair or null on error.  */
429 
430 typedef struct xtensa_funcUnit_use_struct
431 {
432   xtensa_funcUnit unit;
433   int stage;
434 } xtensa_funcUnit_use;
435 
436 extern int
437 xtensa_opcode_num_funcUnit_uses (xtensa_isa isa, xtensa_opcode opc);
438 
439 extern xtensa_funcUnit_use *
440 xtensa_opcode_funcUnit_use (xtensa_isa isa, xtensa_opcode opc, int u);
441 
442 
443 
444 /* Operand information.  */
445 
446 /* Get the name of an operand.  Returns null on error.  */
447 
448 extern const char *
449 xtensa_operand_name (xtensa_isa isa, xtensa_opcode opc, int opnd);
450 
451 
452 /* Some operands are "invisible", i.e., not explicitly specified in
453    assembly language.  When assembling an instruction, you need not set
454    the values of invisible operands, since they are either hardwired or
455    derived from other field values.  The values of invisible operands
456    can be examined in the same way as other operands, but remember that
457    an invisible operand may get its value from another visible one, so
458    the entire instruction must be available before examining the
459    invisible operand values.  This function returns 1 if an operand is
460    visible, 0 if it is invisible, or XTENSA_UNDEFINED on error.  Note
461    that whether an operand is visible is orthogonal to whether it is
462    "implicit", i.e., whether it is encoded in a field in the
463    instruction.  */
464 
465 extern int
466 xtensa_operand_is_visible (xtensa_isa isa, xtensa_opcode opc, int opnd);
467 
468 
469 /* Check if an operand is an input ('i'), output ('o'), or inout ('m')
470    operand.  Note: The output operand of a conditional assignment
471    (e.g., movnez) appears here as an inout ('m') even if it is declared
472    in the TIE code as an output ('o'); this allows the compiler to
473    properly handle register allocation for conditional assignments.
474    Returns 0 on error.  */
475 
476 extern char
477 xtensa_operand_inout (xtensa_isa isa, xtensa_opcode opc, int opnd);
478 
479 
480 /* Get and set the raw (encoded) value of the field for the specified
481    operand.  The "set" function does not check if the value fits in the
482    field; that is done by the "encode" function below.  Both of these
483    functions return non-zero on error, e.g., if the field is not defined
484    for the specified slot.  */
485 
486 extern int
487 xtensa_operand_get_field (xtensa_isa isa, xtensa_opcode opc, int opnd,
488 			  xtensa_format fmt, int slot,
489 			  const xtensa_insnbuf slotbuf, uint32 *valp);
490 
491 extern int
492 xtensa_operand_set_field (xtensa_isa isa, xtensa_opcode opc, int opnd,
493 			  xtensa_format fmt, int slot,
494 			  xtensa_insnbuf slotbuf, uint32 val);
495 
496 
497 /* Encode and decode operands.  The raw bits in the operand field may
498    be encoded in a variety of different ways.  These functions hide
499    the details of that encoding.  The result values are returned through
500    the argument pointer.  The return value is non-zero on error.  */
501 
502 extern int
503 xtensa_operand_encode (xtensa_isa isa, xtensa_opcode opc, int opnd,
504 		       uint32 *valp);
505 
506 extern int
507 xtensa_operand_decode (xtensa_isa isa, xtensa_opcode opc, int opnd,
508 		       uint32 *valp);
509 
510 
511 /* An operand may be either a register operand or an immediate of some
512    sort (e.g., PC-relative or not).  The "is_register" function returns
513    0 if the operand is an immediate, 1 if it is a register, and
514    XTENSA_UNDEFINED on error.  The "regfile" function returns the
515    regfile for a register operand, or XTENSA_UNDEFINED on error.  */
516 
517 extern int
518 xtensa_operand_is_register (xtensa_isa isa, xtensa_opcode opc, int opnd);
519 
520 extern xtensa_regfile
521 xtensa_operand_regfile (xtensa_isa isa, xtensa_opcode opc, int opnd);
522 
523 
524 /* Register operands may span multiple consecutive registers, e.g., a
525    64-bit data type may occupy two 32-bit registers.  Only the first
526    register is encoded in the operand field.  This function specifies
527    the number of consecutive registers occupied by this operand.  For
528    non-register operands, the return value is undefined.  Returns
529    XTENSA_UNDEFINED on error.  */
530 
531 extern int
532 xtensa_operand_num_regs (xtensa_isa isa, xtensa_opcode opc, int opnd);
533 
534 
535 /* Some register operands do not completely identify the register being
536    accessed.  For example, the operand value may be added to an internal
537    state value.  By definition, this implies that the corresponding
538    regfile is not allocatable.  Unknown registers should generally be
539    treated with worst-case assumptions.  The function returns 0 if the
540    register value is unknown, 1 if known, and XTENSA_UNDEFINED on
541    error.  */
542 
543 extern int
544 xtensa_operand_is_known_reg (xtensa_isa isa, xtensa_opcode opc, int opnd);
545 
546 
547 /* Check if an immediate operand is PC-relative.  Returns 0 for register
548    operands and non-PC-relative immediates, 1 for PC-relative
549    immediates, and XTENSA_UNDEFINED on error.  */
550 
551 extern int
552 xtensa_operand_is_PCrelative (xtensa_isa isa, xtensa_opcode opc, int opnd);
553 
554 
555 /* For PC-relative offset operands, the interpretation of the offset may
556    vary between opcodes, e.g., is it relative to the current PC or that
557    of the next instruction?  The following functions are defined to
558    perform PC-relative relocations and to undo them (as in the
559    disassembler).  The "do_reloc" function takes the desired address
560    value and the PC of the current instruction and sets the value to the
561    corresponding PC-relative offset (which can then be encoded and
562    stored into the operand field).  The "undo_reloc" function takes the
563    unencoded offset value and the current PC and sets the value to the
564    appropriate address.  The return values are non-zero on error.  Note
565    that these functions do not replace the encode/decode functions; the
566    operands must be encoded/decoded separately and the encode functions
567    are responsible for detecting invalid operand values.  */
568 
569 extern int
570 xtensa_operand_do_reloc (xtensa_isa isa, xtensa_opcode opc, int opnd,
571 			 uint32 *valp, uint32 pc);
572 
573 extern int
574 xtensa_operand_undo_reloc (xtensa_isa isa, xtensa_opcode opc, int opnd,
575 			   uint32 *valp, uint32 pc);
576 
577 
578 
579 /* State Operands.  */
580 
581 /* Get the state accessed by a state operand.  Returns XTENSA_UNDEFINED
582    on error.  */
583 
584 extern xtensa_state
585 xtensa_stateOperand_state (xtensa_isa isa, xtensa_opcode opc, int stOp);
586 
587 
588 /* Check if a state operand is an input ('i'), output ('o'), or inout
589    ('m') operand.  Returns 0 on error.  */
590 
591 extern char
592 xtensa_stateOperand_inout (xtensa_isa isa, xtensa_opcode opc, int stOp);
593 
594 
595 
596 /* Interface Operands.  */
597 
598 /* Get the external interface accessed by an interface operand.
599    Returns XTENSA_UNDEFINED on error.  */
600 
601 extern xtensa_interface
602 xtensa_interfaceOperand_interface (xtensa_isa isa, xtensa_opcode opc,
603 				   int ifOp);
604 
605 
606 
607 /* Register Files.  */
608 
609 /* Regfiles include both "real" regfiles and "views", where a view
610    allows a group of adjacent registers in a real "parent" regfile to be
611    viewed as a single register.  A regfile view has all the same
612    properties as its parent except for its (long) name, bit width, number
613    of entries, and default ctype.  You can use the parent function to
614    distinguish these two classes.  */
615 
616 /* Look up a regfile by either its name or its abbreviated "short name".
617    Returns XTENSA_UNDEFINED on error.  The "lookup_shortname" function
618    ignores "view" regfiles since they always have the same shortname as
619    their parents.  */
620 
621 extern xtensa_regfile
622 xtensa_regfile_lookup (xtensa_isa isa, const char *name);
623 
624 extern xtensa_regfile
625 xtensa_regfile_lookup_shortname (xtensa_isa isa, const char *shortname);
626 
627 
628 /* Get the name or abbreviated "short name" of a regfile.
629    Returns null on error.  */
630 
631 extern const char *
632 xtensa_regfile_name (xtensa_isa isa, xtensa_regfile rf);
633 
634 extern const char *
635 xtensa_regfile_shortname (xtensa_isa isa, xtensa_regfile rf);
636 
637 
638 /* Get the parent regfile of a "view" regfile.  If the regfile is not a
639    view, the result is the same as the input parameter.  Returns
640    XTENSA_UNDEFINED on error.  */
641 
642 extern xtensa_regfile
643 xtensa_regfile_view_parent (xtensa_isa isa, xtensa_regfile rf);
644 
645 
646 /* Get the bit width of a regfile or regfile view.
647    Returns XTENSA_UNDEFINED on error.  */
648 
649 extern int
650 xtensa_regfile_num_bits (xtensa_isa isa, xtensa_regfile rf);
651 
652 
653 /* Get the number of regfile entries.  Returns XTENSA_UNDEFINED on
654    error.  */
655 
656 extern int
657 xtensa_regfile_num_entries (xtensa_isa isa, xtensa_regfile rf);
658 
659 
660 
661 /* Processor States.  */
662 
663 /* Look up a state by name.  Returns XTENSA_UNDEFINED on error.  */
664 
665 extern xtensa_state
666 xtensa_state_lookup (xtensa_isa isa, const char *name);
667 
668 
669 /* Get the name for a processor state.  Returns null on error.  */
670 
671 extern const char *
672 xtensa_state_name (xtensa_isa isa, xtensa_state st);
673 
674 
675 /* Get the bit width for a processor state.
676    Returns XTENSA_UNDEFINED on error.  */
677 
678 extern int
679 xtensa_state_num_bits (xtensa_isa isa, xtensa_state st);
680 
681 
682 /* Check if a state is exported from the processor core.  Returns 0 if
683    the condition is false, 1 if the condition is true, and
684    XTENSA_UNDEFINED on error.  */
685 
686 extern int
687 xtensa_state_is_exported (xtensa_isa isa, xtensa_state st);
688 
689 
690 /* Check for a "shared_or" state.  Returns 0 if the condition is false,
691    1 if the condition is true, and XTENSA_UNDEFINED on error.  */
692 
693 extern int
694 xtensa_state_is_shared_or (xtensa_isa isa, xtensa_state st);
695 
696 
697 
698 /* Sysregs ("special registers" and "user registers").  */
699 
700 /* Look up a register by its number and whether it is a "user register"
701    or a "special register".  Returns XTENSA_UNDEFINED if the sysreg does
702    not exist.  */
703 
704 extern xtensa_sysreg
705 xtensa_sysreg_lookup (xtensa_isa isa, int num, int is_user);
706 
707 
708 /* Check if there exists a sysreg with a given name.
709    If not, this function returns XTENSA_UNDEFINED.  */
710 
711 extern xtensa_sysreg
712 xtensa_sysreg_lookup_name (xtensa_isa isa, const char *name);
713 
714 
715 /* Get the name of a sysreg.  Returns null on error.  */
716 
717 extern const char *
718 xtensa_sysreg_name (xtensa_isa isa, xtensa_sysreg sysreg);
719 
720 
721 /* Get the register number.  Returns XTENSA_UNDEFINED on error.  */
722 
723 extern int
724 xtensa_sysreg_number (xtensa_isa isa, xtensa_sysreg sysreg);
725 
726 
727 /* Check if a sysreg is a "special register" or a "user register".
728    Returns 0 for special registers, 1 for user registers and
729    XTENSA_UNDEFINED on error.  */
730 
731 extern int
732 xtensa_sysreg_is_user (xtensa_isa isa, xtensa_sysreg sysreg);
733 
734 
735 
736 /* Interfaces.  */
737 
738 /* Find an interface by name.  The return value is XTENSA_UNDEFINED if
739    the specified interface is not found.  */
740 
741 extern xtensa_interface
742 xtensa_interface_lookup (xtensa_isa isa, const char *ifname);
743 
744 
745 /* Get the name of an interface.  Returns null on error.  */
746 
747 extern const char *
748 xtensa_interface_name (xtensa_isa isa, xtensa_interface intf);
749 
750 
751 /* Get the bit width for an interface.
752    Returns XTENSA_UNDEFINED on error.  */
753 
754 extern int
755 xtensa_interface_num_bits (xtensa_isa isa, xtensa_interface intf);
756 
757 
758 /* Check if an interface is an input ('i') or output ('o') with respect
759    to the Xtensa processor core.  Returns 0 on error.  */
760 
761 extern char
762 xtensa_interface_inout (xtensa_isa isa, xtensa_interface intf);
763 
764 
765 /* Check if accessing an interface has potential side effects.
766    Currently "data" interfaces have side effects and "control"
767    interfaces do not.  Returns 1 if there are side effects, 0 if not,
768    and XTENSA_UNDEFINED on error.  */
769 
770 extern int
771 xtensa_interface_has_side_effect (xtensa_isa isa, xtensa_interface intf);
772 
773 
774 /* Some interfaces may be related such that accessing one interface
775    has side effects on a set of related interfaces.  The interfaces
776    are partitioned into equivalence classes of related interfaces, and
777    each class is assigned a unique identifier number.  This function
778    returns the class identifier for an interface, or XTENSA_UNDEFINED
779    on error.  These identifiers can be compared to determine if two
780    interfaces are related; the specific values of the identifiers have
781    no particular meaning otherwise.  */
782 
783 extern int
784 xtensa_interface_class_id (xtensa_isa isa, xtensa_interface intf);
785 
786 
787 
788 /* Functional Units.  */
789 
790 /* Find a functional unit by name.  The return value is XTENSA_UNDEFINED if
791    the specified unit is not found.  */
792 
793 extern xtensa_funcUnit
794 xtensa_funcUnit_lookup (xtensa_isa isa, const char *fname);
795 
796 
797 /* Get the name of a functional unit.  Returns null on error.  */
798 
799 extern const char *
800 xtensa_funcUnit_name (xtensa_isa isa, xtensa_funcUnit fun);
801 
802 
803 /* Functional units may be replicated.  See how many instances of a
804    particular function unit exist.  Returns XTENSA_UNDEFINED on error.  */
805 
806 extern int
807 xtensa_funcUnit_num_copies (xtensa_isa isa, xtensa_funcUnit fun);
808 
809 
810 #ifdef __cplusplus
811 }
812 #endif
813 #endif /* XTENSA_LIBISA_H */
814