1/* Table of relaxations for Xtensa assembly.
2   Copyright 2003, 2004 Free Software Foundation, Inc.
3
4   This file is part of GAS, the GNU Assembler.
5
6   GAS 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 2, or (at your option)
9   any later version.
10
11   GAS 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 GAS; see the file COPYING.  If not, write to
18   the Free Software Foundation, 51 Franklin Street - Fifth Floor, Boston,
19   MA 02110-1301, USA.  */
20
21#ifndef XTENSA_RELAX_H
22#define XTENSA_RELAX_H
23
24#include "xtensa-isa.h"
25
26
27/* Data structures for the table-driven relaxations for Xtensa processors.
28   See xtensa-relax.c for details.  */
29
30typedef struct transition_list TransitionList;
31typedef struct transition_table TransitionTable;
32typedef struct transition_rule TransitionRule;
33typedef struct precondition_list PreconditionList;
34typedef struct precondition Precondition;
35
36typedef struct req_or_option_list ReqOrOptionList;
37typedef struct req_or_option_list ReqOrOption;
38typedef struct req_option_list ReqOptionList;
39typedef struct req_option_list ReqOption;
40
41struct transition_table
42{
43  int num_opcodes;
44  TransitionList **table;	/* Possible transitions for each opcode.  */
45};
46
47struct transition_list
48{
49  TransitionRule *rule;
50  TransitionList *next;
51};
52
53struct precondition_list
54{
55  Precondition *precond;
56  PreconditionList *next;
57};
58
59
60/* The required options for a rule are represented with a two-level
61   structure, with leaf expressions combined by logical ORs at the
62   lower level, and the results then combined by logical ANDs at the
63   top level.  The AND terms are linked in a list, and each one can
64   contain a reference to a list of OR terms.  The leaf expressions,
65   i.e., the OR options, can be negated by setting the is_true field
66   to FALSE.  There are two classes of leaf expressions: (1) those
67   that are properties of the Xtensa configuration and can be
68   evaluated once when building the tables, and (2) those that depend
69   of the state of directives or other settings that may vary during
70   the assembly.  The following expressions may be used in group (1):
71
72   IsaUse*:	Xtensa configuration settings.
73   realnop:	TRUE if the instruction set includes a NOP instruction.
74
75   There are currently no expressions in group (2), but they are still
76   supported since there is a good chance they'll be needed again for
77   something.  */
78
79struct req_option_list
80{
81  ReqOrOptionList *or_option_terms;
82  ReqOptionList *next;
83};
84
85struct req_or_option_list
86{
87  char *option_name;
88  bfd_boolean is_true;
89  ReqOrOptionList *next;
90};
91
92/* Operand types and constraints on operands:  */
93
94typedef enum op_type OpType;
95typedef enum cmp_op CmpOp;
96
97enum op_type
98{
99  OP_CONSTANT,
100  OP_OPERAND,
101  OP_OPERAND_LOW8,		/* Sign-extended low 8 bits of immed.  */
102  OP_OPERAND_HI24S,		/* High 24 bits of immed,
103				   plus 0x100 if low 8 bits are signed.  */
104  OP_OPERAND_F32MINUS,		/* 32 - immed.  */
105  OP_OPERAND_LOW16U,		/* Low 16 bits of immed.  */
106  OP_OPERAND_HI16U,		/* High 16 bits of immed.  */
107  OP_LITERAL,
108  OP_LABEL
109};
110
111enum cmp_op
112{
113  OP_EQUAL,
114  OP_NOTEQUAL,
115};
116
117struct precondition
118{
119  CmpOp cmp;
120  int op_num;
121  OpType typ;			/* CONSTANT: op_data is a constant.
122				   OPERAND: operand op_num must equal op_data.
123				   Cannot be LITERAL or LABEL.  */
124  int op_data;
125};
126
127
128typedef struct build_op BuildOp;
129
130struct build_op
131{
132  int op_num;
133  OpType typ;
134  unsigned op_data;		/* CONSTANT: op_data is the value to encode.
135				   OPERAND: op_data is the field in the
136				   source instruction to take the value from
137				   and encode in the op_num field here.
138				   LITERAL or LABEL: op_data is the ordinal
139				   that identifies the appropriate one, i.e.,
140				   there can be more than one literal or
141				   label in an expansion.  */
142  BuildOp *next;
143};
144
145typedef struct build_instr BuildInstr;
146typedef enum instr_type InstrType;
147
148enum instr_type
149{
150  INSTR_INSTR,
151  INSTR_LITERAL_DEF,
152  INSTR_LABEL_DEF
153};
154
155struct build_instr
156{
157  InstrType typ;
158  unsigned id;			/* LITERAL_DEF or LABEL_DEF: an ordinal to
159				   identify which one.  */
160  xtensa_opcode opcode;		/* Unused for LITERAL_DEF or LABEL_DEF.  */
161  BuildOp *ops;
162  BuildInstr *next;
163};
164
165struct transition_rule
166{
167  xtensa_opcode opcode;
168  PreconditionList *conditions;
169  ReqOptionList *options;
170  BuildInstr *to_instr;
171};
172
173typedef int (*transition_cmp_fn) (const TransitionRule *,
174				  const TransitionRule *);
175
176extern TransitionTable *xg_build_simplify_table (transition_cmp_fn);
177extern TransitionTable *xg_build_widen_table (transition_cmp_fn);
178
179extern bfd_boolean xg_has_userdef_op_fn (OpType);
180extern long xg_apply_userdef_op_fn (OpType, long);
181
182#endif /* !XTENSA_RELAX_H */
183