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authorNick Clifton <nickc@redhat.com>2003-04-01 15:50:31 +0000
committerNick Clifton <nickc@redhat.com>2003-04-01 15:50:31 +0000
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tree4676b72e452f4dfc81e8d6646fb43f63a108da1b /include/xtensa-isa.h
parentce0c72625ad0f6497718b4293572b2b6be711714 (diff)
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Add Xtensa port
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diff --git a/include/xtensa-isa.h b/include/xtensa-isa.h
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+/* Interface definition for configurable Xtensa ISA support.
+ Copyright 2003 Free Software Foundation, Inc.
+
+ This file is part of BFD, the Binary File Descriptor library.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+
+#ifndef XTENSA_LIBISA_H
+#define XTENSA_LIBISA_H
+
+/* Use the statically-linked version for the GNU tools. */
+#define STATIC_LIBISA 1
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef uint32
+#define uint32 unsigned int
+#endif
+
+/* This file defines the interface to the Xtensa ISA library. This library
+ contains most of the ISA-specific information for a particular Xtensa
+ processor. For example, the set of valid instructions, their opcode
+ encodings and operand fields are all included here. To support Xtensa's
+ configurability and user-defined instruction extensions (i.e., TIE), the
+ library is initialized by loading one or more dynamic libraries; only a
+ small set of interface code is present in the statically-linked portion
+ of the library.
+
+ This interface basically defines four abstract data types.
+
+ . an instruction buffer - for holding the raw instruction bits
+ . ISA info - information about the ISA as a whole
+ . opcode info - information about individual instructions
+ . operand info - information about specific instruction operands
+
+ It would be nice to implement these as classes in C++, but the library is
+ implemented in C to match the expectations of the GNU tools.
+ Instead, the interface defines a set of functions to access each data
+ type. With the exception of the instruction buffer, the internal
+ representations of the data structures are hidden. All accesses must be
+ made through the functions defined here. */
+
+typedef void* xtensa_isa;
+typedef void* xtensa_operand;
+
+
+/* Opcodes are represented here using sequential integers beginning with 0.
+ The specific value used for a particular opcode is only fixed for a
+ particular instantiation of an xtensa_isa structure, so these values
+ should only be used internally. */
+typedef int xtensa_opcode;
+
+/* Define a unique value for undefined opcodes ("static const int" doesn't
+ seem to work for this because EGCS 1.0.3 on i686-Linux without -O won't
+ allow it to be used as an initializer). */
+#define XTENSA_UNDEFINED -1
+
+
+typedef int libisa_module_specifier;
+
+extern xtensa_isa xtensa_isa_init (void);
+
+
+/* Instruction buffers. */
+
+typedef uint32 xtensa_insnbuf_word;
+typedef xtensa_insnbuf_word *xtensa_insnbuf;
+
+/* Get the size in words of the xtensa_insnbuf array. */
+extern int xtensa_insnbuf_size (xtensa_isa);
+
+/* Allocate (with malloc) an xtensa_insnbuf of the right size. */
+extern xtensa_insnbuf xtensa_insnbuf_alloc (xtensa_isa);
+
+/* Release (with free) an xtensa_insnbuf of the right size. */
+extern void xtensa_insnbuf_free (xtensa_insnbuf);
+
+/* Inward and outward conversion from memory images (byte streams) to our
+ internal instruction representation. */
+extern void xtensa_insnbuf_to_chars (xtensa_isa, const xtensa_insnbuf,
+ char *);
+
+extern void xtensa_insnbuf_from_chars (xtensa_isa, xtensa_insnbuf,
+ const char *);
+
+
+/* ISA information. */
+
+/* Load the ISA information from a shared library. If successful, this returns
+ a value which identifies the ISA for use in subsequent calls to the ISA
+ library; otherwise, it returns NULL. Multiple ISAs can be loaded to support
+ heterogeneous multiprocessor systems. */
+extern xtensa_isa xtensa_load_isa (libisa_module_specifier);
+
+/* Extend an existing set of ISA information by loading an additional shared
+ library of ISA information. This is primarily intended for loading TIE
+ extensions. If successful, the return value is non-zero. */
+extern int xtensa_extend_isa (xtensa_isa, libisa_module_specifier);
+
+/* The default ISA. This variable is set automatically to the ISA most
+ recently loaded and is provided as a convenience. An exception is the GNU
+ opcodes library, where there is a fixed interface that does not allow
+ passing the ISA as a parameter and the ISA must be taken from this global
+ variable. (Note: Since this variable is just a convenience, it is not
+ exported when libisa is built as a DLL, due to the hassle of dealing with
+ declspecs.) */
+extern xtensa_isa xtensa_default_isa;
+
+
+/* Deallocate an xtensa_isa structure. */
+extern void xtensa_isa_free (xtensa_isa);
+
+/* Get the maximum instruction size in bytes. */
+extern int xtensa_insn_maxlength (xtensa_isa);
+
+/* Get the total number of opcodes for this processor. */
+extern int xtensa_num_opcodes (xtensa_isa);
+
+/* Translate a mnemonic name to an opcode. Returns XTENSA_UNDEFINED if
+ the name is not a valid opcode mnemonic. */
+extern xtensa_opcode xtensa_opcode_lookup (xtensa_isa, const char *);
+
+/* Decode a binary instruction buffer. Returns the opcode or
+ XTENSA_UNDEFINED if the instruction is illegal. */
+extern xtensa_opcode xtensa_decode_insn (xtensa_isa, const xtensa_insnbuf);
+
+
+/* Opcode information. */
+
+/* Set the opcode field(s) in a binary instruction buffer. The operand
+ fields are set to zero. */
+extern void xtensa_encode_insn (xtensa_isa, xtensa_opcode, xtensa_insnbuf);
+
+/* Get the mnemonic name for an opcode. */
+extern const char * xtensa_opcode_name (xtensa_isa, xtensa_opcode);
+
+/* Find the length (in bytes) of an instruction. */
+extern int xtensa_insn_length (xtensa_isa, xtensa_opcode);
+
+/* Find the length of an instruction by looking only at the first byte. */
+extern int xtensa_insn_length_from_first_byte (xtensa_isa, char);
+
+/* Find the number of operands for an instruction. */
+extern int xtensa_num_operands (xtensa_isa, xtensa_opcode);
+
+/* Get the information about operand number "opnd" of a particular opcode. */
+extern xtensa_operand xtensa_get_operand (xtensa_isa, xtensa_opcode, int);
+
+/* Operand information. */
+
+/* Find the kind of operand. There are three possibilities:
+ 1) PC-relative immediates (e.g., "l", "L"). These can be identified with
+ the xtensa_operand_isPCRelative function.
+ 2) non-PC-relative immediates ("i").
+ 3) register-file short names (e.g., "a", "b", "m" and others defined
+ via TIE). */
+extern char * xtensa_operand_kind (xtensa_operand);
+
+/* Check if an operand is an input ('<'), output ('>'), or inout ('=')
+ operand. Note: The output operand of a conditional assignment
+ (e.g., movnez) appears here as an inout ('=') even if it is declared
+ in the TIE code as an output ('>'); this allows the compiler to
+ properly handle register allocation for conditional assignments. */
+extern char xtensa_operand_inout (xtensa_operand);
+
+/* Get and set the raw (encoded) value of the field for the specified
+ operand. The "set" function does not check if the value fits in the
+ field; that is done by the "encode" function below. */
+extern uint32 xtensa_operand_get_field (xtensa_operand, const xtensa_insnbuf);
+
+extern void xtensa_operand_set_field (xtensa_operand, xtensa_insnbuf, uint32);
+
+
+/* Encode and decode operands. The raw bits in the operand field
+ may be encoded in a variety of different ways. These functions hide the
+ details of that encoding. The encode function has a special return type
+ (xtensa_encode_result) to indicate success or the reason for failure; the
+ encoded value is returned through the argument pointer. The decode function
+ has no possibility of failure and returns the decoded value. */
+
+typedef enum
+{
+ xtensa_encode_result_ok,
+ xtensa_encode_result_align,
+ xtensa_encode_result_not_in_table,
+ xtensa_encode_result_too_low,
+ xtensa_encode_result_too_high,
+ xtensa_encode_result_not_ok,
+ xtensa_encode_result_max = xtensa_encode_result_not_ok
+} xtensa_encode_result;
+
+extern xtensa_encode_result xtensa_operand_encode (xtensa_operand, uint32 *);
+
+extern uint32 xtensa_operand_decode (xtensa_operand, uint32);
+
+
+/* For PC-relative offset operands, the interpretation of the offset may vary
+ between opcodes, e.g., is it relative to the current PC or that of the next
+ instruction? The following functions are defined to perform PC-relative
+ relocations and to undo them (as in the disassembler). The first function
+ takes the desired address and the PC of the current instruction and returns
+ the unencoded value to be stored in the offset field. The second function
+ takes the unencoded offset value and the current PC and returns the address.
+ Note that these functions do not replace the encode/decode functions; the
+ operands must be encoded/decoded separately. */
+
+extern int xtensa_operand_isPCRelative (xtensa_operand);
+
+extern uint32 xtensa_operand_do_reloc (xtensa_operand, uint32, uint32);
+
+extern uint32 xtensa_operand_undo_reloc (xtensa_operand, uint32, uint32);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* XTENSA_LIBISA_H */