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1.1 root 1: /* i386.h -- Header file for i386.c
2: Copyright (C) 1989, Free Software Foundation.
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 1, 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, 675 Mass Ave, Cambridge, MA 02139, USA. */
19:
20: #define MAX_OPERANDS 3 /* max operands per insn */
21: #define MAX_PREFIXES 4 /* max prefixes per opcode */
22: #define MAX_IMMEDIATE_OPERANDS 2 /* max immediates per insn */
23: #define MAX_MEMORY_OPERANDS 2 /* max memory ref per insn
24: * lcall uses 2
25: */
26: /* we define the syntax here (modulo base,index,scale syntax) */
27: #define REGISTER_PREFIX '%'
28: #define IMMEDIATE_PREFIX '$'
29: #define ABSOLUTE_PREFIX '*'
30: #define PREFIX_SEPERATOR '/'
31:
32: #define TWO_BYTE_OPCODE_ESCAPE 0x0f
33:
34: /* register numbers */
35: #define EBP_REG_NUM 5
36: #define ESP_REG_NUM 4
37:
38: /* modrm_byte.regmem for twobyte escape */
39: #define ESCAPE_TO_TWO_BYTE_ADDRESSING ESP_REG_NUM
40: /* index_base_byte.index for no index register addressing */
41: #define NO_INDEX_REGISTER ESP_REG_NUM
42: /* index_base_byte.base for no base register addressing */
43: #define NO_BASE_REGISTER EBP_REG_NUM
44:
45: /* these are the att as opcode suffixes, making movl --> mov, for example */
46: #define DWORD_OPCODE_SUFFIX 'l'
47: #define WORD_OPCODE_SUFFIX 'w'
48: #define BYTE_OPCODE_SUFFIX 'b'
49:
50: /* modrm.mode = REGMEM_FIELD_HAS_REG when a register is in there */
51: #define REGMEM_FIELD_HAS_REG 0x3 /* always = 0x3 */
52: #define REGMEM_FIELD_HAS_MEM (~REGMEM_FIELD_HAS_REG)
53:
54: #define END_OF_INSN '\0'
55:
56: /*
57: When an operand is read in it is classified by its type. This type includes
58: all the possible ways an operand can be used. Thus, '%eax' is both 'register
59: # 0' and 'The Accumulator'. In our language this is expressed by OR'ing
60: 'Reg32' (any 32 bit register) and 'Acc' (the accumulator).
61: Operands are classified so that we can match given operand types with
62: the opcode table in i386-opcode.h.
63: */
64: #define Unknown 0x0
65: /* register */
66: #define Reg8 0x1 /* 8 bit reg */
67: #define Reg16 0x2 /* 16 bit reg */
68: #define Reg32 0x4 /* 32 bit reg */
69: #define Reg (Reg8|Reg16|Reg32) /* gen'l register */
70: #define WordReg (Reg16|Reg32) /* for push/pop operands */
71: /* immediate */
72: #define Imm8 0x8 /* 8 bit immediate */
73: #define Imm8S 0x10 /* 8 bit immediate sign extended */
74: #define Imm16 0x20 /* 16 bit immediate */
75: #define Imm32 0x40 /* 32 bit immediate */
76: #define Imm1 0x80 /* 1 bit immediate */
77: #define ImmUnknown Imm32 /* for unknown expressions */
78: #define Imm (Imm8|Imm8S|Imm16|Imm32) /* gen'l immediate */
79: /* memory */
80: #define Disp8 0x200 /* 8 bit displacement (for jumps) */
81: #define Disp16 0x400 /* 16 bit displacement */
82: #define Disp32 0x800 /* 32 bit displacement */
83: #define Disp (Disp8|Disp16|Disp32) /* General displacement */
84: #define DispUnknown Disp32 /* for unknown size displacements */
85: #define Mem8 0x1000
86: #define Mem16 0x2000
87: #define Mem32 0x4000
88: #define BaseIndex 0x8000
89: #define Mem (Disp|Mem8|Mem16|Mem32|BaseIndex) /* General memory */
90: #define WordMem (Mem16|Mem32|Disp|BaseIndex)
91: #define ByteMem (Mem8|Disp|BaseIndex)
92: /* specials */
93: #define InOutPortReg 0x10000 /* register to hold in/out port addr = dx */
94: #define ShiftCount 0x20000 /* register to hold shift cound = cl */
95: #define Control 0x40000 /* Control register */
96: #define Debug 0x80000 /* Debug register */
97: #define Test 0x100000 /* Test register */
98: #define FloatReg 0x200000 /* Float register */
99: #define FloatAcc 0x400000 /* Float stack top %st(0) */
100: #define SReg2 0x800000 /* 2 bit segment register */
101: #define SReg3 0x1000000 /* 3 bit segment register */
102: #define Acc 0x2000000 /* Accumulator %al or %ax or %eax */
103: #define ImplicitRegister (InOutPortReg|ShiftCount|Acc|FloatAcc)
104: #define JumpAbsolute 0x4000000
105: #define Abs8 0x08000000
106: #define Abs16 0x10000000
107: #define Abs32 0x20000000
108: #define Abs (Abs8|Abs16|Abs32)
109:
110: #define MODE_FROM_DISP_SIZE(t) \
111: ((t&(Disp8)) ? 1 : \
112: ((t&(Disp32)) ? 2 : 0))
113:
114: #define Byte (Reg8|Imm8|Imm8S)
115: #define Word (Reg16|Imm16)
116: #define DWord (Reg32|Imm32)
117:
118: /* convert opcode suffix ('b' 'w' 'l' typically) into type specifyer */
119: #define OPCODE_SUFFIX_TO_TYPE(s) \
120: (s == BYTE_OPCODE_SUFFIX ? Byte : \
121: (s == WORD_OPCODE_SUFFIX ? Word : DWord))
122:
123: #define FITS_IN_SIGNED_BYTE(num) ((num) >= -128 && (num) <= 127)
124: #define FITS_IN_UNSIGNED_BYTE(num) ((num) >= 0 && (num) <= 255)
125: #define FITS_IN_UNSIGNED_WORD(num) ((num) >= 0 && (num) <= 65535)
126: #define FITS_IN_SIGNED_WORD(num) ((num) >= -32768 && (num) <= 32767)
127:
128: #define SMALLEST_DISP_TYPE(num) \
129: FITS_IN_SIGNED_BYTE(num) ? (Disp8|Disp32|Abs8|Abs32) : (Disp32|Abs32)
130:
131: #define SMALLEST_IMM_TYPE(num) \
132: (num == 1) ? (Imm1|Imm8|Imm8S|Imm16|Imm32): \
133: FITS_IN_SIGNED_BYTE(num) ? (Imm8S|Imm8|Imm16|Imm32) : \
134: FITS_IN_UNSIGNED_BYTE(num) ? (Imm8|Imm16|Imm32): \
135: (FITS_IN_SIGNED_WORD(num)||FITS_IN_UNSIGNED_WORD(num)) ? (Imm16|Imm32) : \
136: (Imm32)
137:
138: typedef unsigned char uchar;
139: typedef unsigned int uint;
140:
141: typedef struct {
142: /* instruction name sans width suffix ("mov" for movl insns) */
143: char *name;
144:
145: /* how many operands */
146: uint operands;
147:
148: /* base_opcode is the fundamental opcode byte with a optional prefix(es). */
149: uint base_opcode;
150:
151: /* extension_opcode is the 3 bit extension for group <n> insns.
152: If this template has no extension opcode (the usual case) use None */
153: uchar extension_opcode;
154: #define None 0xff /* If no extension_opcode is possible. */
155:
156: /* the bits in opcode_modifier are used to generate the final opcode from
157: the base_opcode. These bits also are used to detect alternate forms of
158: the same instruction */
159: uint opcode_modifier;
160:
161: /* opcode_modifier bits: */
162: #define W 0x1 /* set if operands are words or dwords */
163: #define D 0x2 /* D = 0 if Reg --> Regmem; D = 1 if Regmem --> Reg */
164: /* direction flag for floating insns: MUST BE 0x400 */
165: #define FloatD 0x400
166: /* shorthand */
167: #define DW (D|W)
168: #define ShortForm 0x10 /* register is in low 3 bits of opcode */
169: #define ShortFormW 0x20 /* ShortForm and W bit is 0x8 */
170: #define Seg2ShortForm 0x40 /* encoding of load segment reg insns */
171: #define Seg3ShortForm 0x80 /* fs/gs segment register insns. */
172: #define Jump 0x100 /* special case for jump insns. */
173: #define JumpInterSegment 0x200 /* special case for intersegment leaps/calls */
174: /* 0x400 CANNOT BE USED since it's already used by FloatD above */
175: #define DONT_USE 0x400
176: #define NoModrm 0x800
177: #define Modrm 0x1000
178: #define imulKludge 0x2000
179: #define JumpByte 0x4000
180: #define JumpDword 0x8000
181: #define ReverseRegRegmem 0x10000
182:
183: /* (opcode_modifier & COMES_IN_ALL_SIZES) is true if the
184: instuction comes in byte, word, and dword sizes and is encoded into
185: machine code in the canonical way. */
186: #define COMES_IN_ALL_SIZES (W)
187:
188: /* (opcode_modifier & COMES_IN_BOTH_DIRECTIONS) indicates that the
189: source and destination operands can be reversed by setting either
190: the D (for integer insns) or the FloatD (for floating insns) bit
191: in base_opcode. */
192: #define COMES_IN_BOTH_DIRECTIONS (D|FloatD)
193:
194: /* operand_types[i] describes the type of operand i. This is made
195: by OR'ing together all of the possible type masks. (e.g.
196: 'operand_types[i] = Reg|Imm' specifies that operand i can be
197: either a register or an immediate operand */
198: uint operand_types[3];
199: #ifdef NeXT
200: char *cpus;
201: #endif /* NeXT */
202: } template;
203:
204: /*
205: 'templates' is for grouping together 'template' structures for opcodes
206: of the same name. This is only used for storing the insns in the grand
207: ole hash table of insns.
208: The templates themselves start at START and range up to (but not including)
209: END.
210: */
211: typedef struct {
212: template *start;
213: template *end;
214: } templates;
215:
216: /* these are for register name --> number & type hash lookup */
217: typedef struct {
218: char * reg_name;
219: uint reg_type;
220: uint reg_num;
221: } reg_entry;
222:
223: typedef struct {
224: char * seg_name;
225: uint seg_prefix;
226: } seg_entry;
227:
228: /* these are for prefix name --> prefix code hash lookup */
229: typedef struct {
230: char * prefix_name;
231: uchar prefix_code;
232: } prefix_entry;
233:
234: /* 386 operand encoding bytes: see 386 book for details of this. */
235: typedef struct {
236: unsigned regmem:3; /* codes register or memory operand */
237: unsigned reg:3; /* codes register operand (or extended opcode) */
238: unsigned mode:2; /* how to interpret regmem & reg */
239: } modrm_byte;
240:
241: /* 386 opcode byte to code indirect addressing. */
242: typedef struct {
243: unsigned base:3;
244: unsigned index:3;
245: unsigned scale:2;
246: } base_index_byte;
247:
248: /* 'md_assemble ()' gathers together information and puts it into a
249: i386_insn. */
250:
251: typedef struct {
252: /* TM holds the template for the insn were currently assembling. */
253: template tm;
254: /* SUFFIX holds the opcode suffix (e.g. 'l' for 'movl') if given. */
255: char suffix;
256: /* Operands are coded with OPERANDS, TYPES, DISPS, IMMS, and REGS. */
257:
258: /* OPERANDS gives the number of given operands. */
259: uint operands;
260:
261: /* REG_OPERANDS, DISP_OPERANDS, MEM_OPERANDS, IMM_OPERANDS give the number of
262: given register, displacement, memory operands and immediate operands. */
263: uint reg_operands, disp_operands, mem_operands, imm_operands;
264:
265: /* TYPES [i] is the type (see above #defines) which tells us how to
266: search through DISPS [i] & IMMS [i] & REGS [i] for the required
267: operand. */
268: uint types [MAX_OPERANDS];
269:
270: /* Displacements (if given) for each operand. */
271: expressionS * disps [MAX_OPERANDS];
272:
273: /* Immediate operands (if given) for each operand. */
274: expressionS * imms [MAX_OPERANDS];
275:
276: /* Register operands (if given) for each operand. */
277: reg_entry * regs [MAX_OPERANDS];
278:
279: /* BASE_REG, INDEX_REG, and LOG2_SCALE_FACTOR are used to encode
280: the base index byte below. */
281: reg_entry * base_reg;
282: reg_entry * index_reg;
283: uint log2_scale_factor;
284:
285: /* SEG gives the seg_entry of this insn. It is equal to zero unless
286: an explicit segment override is given. */
287: const seg_entry * seg; /* segment for memory operands (if given) */
288: #ifdef NeXT
289: /* BASE_REG, INDEX_REG, and LOG2_SCALE_FACTOR are used to encode
290: the base index byte below. */
291: reg_entry * base_reg2nd;
292: reg_entry * index_reg2nd;
293: uint log2_scale_factor2nd;
294:
295: /* SEG gives the seg_entry of this insn. It is equal to zero unless
296: an explicit segment override is given. */
297: const seg_entry * seg2nd; /* segment for memory operands (if given) */
298: #endif /* NeXT */
299:
300: /* PREFIX holds all the given prefix opcodes (usually null).
301: PREFIXES is the size of PREFIX. */
302: char prefix [MAX_PREFIXES];
303: uint prefixes;
304:
305: /* RM and IB are the modrm byte and the base index byte where the addressing
306: modes of this insn are encoded. */
307:
308: modrm_byte rm;
309: base_index_byte bi;
310: } i386_insn;
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