/* Header for constant multiple table for TILE-Gx.
   Copyright (C) 2011-2021 Free Software Foundation, Inc.
   Contributed by Walter Lee (walt@tilera.com)

   This file is part of GCC.

   GCC 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 3, or (at your
   option) any later version.

   GCC 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 GCC; see the file COPYING3.  If not see
   <http://www.gnu.org/licenses/>.  */

#ifndef GCC_TILEGX_MULTIPLY_H
#define GCC_TILEGX_MULTIPLY_H

/* A node of a tilegx_multiply_insn_seq, corresponding to a single
   machine instruction such as 'add', 's1a', or an shl by a constant.  */
struct tilegx_multiply_insn_seq_entry
{
  /* Which operation this node performs (e.g. an add or sub).
     Don't use this directly, call get_opcode() table to get a insn_code.  */
  unsigned char compressed_opcode;

  /* The left-hand side of this expression tree.
     If equal to 0, it refers to 'zero'.
     If equal to 1, it refers to the original input to the multiply operation.
     Otherwise, subtract two and it is an index into the containing
     tilegx_multiply_insn_seq's 'op' array. Since it can only point to some
     value that has already been computed it will always point to an
     earlier entry in the array.  */
  unsigned char lhs;

  /* This is like lhs, but for the right-hand side. However, for shift
     opcodes this is a shift count rather than an operand index.  */
  unsigned char rhs;
};

/* Maximum size of op array.  */
#define tilegx_multiply_insn_seq_MAX_OPERATIONS 4

/* This defines a DAG describing how to multiply by a constant in
   terms of one or more machine instructions.  */
struct tilegx_multiply_insn_seq
{
  /* The constant factor by which this expression tree multiplies its input.  */
  long long multiplier;

  /* The nodes of the parse tree. These are ordered so that instructions
     can be emitted in the same order that they appear in this array.
     Entry entry in this array can only refer to earlier entries in
     the array.  */
  struct tilegx_multiply_insn_seq_entry
    op[tilegx_multiply_insn_seq_MAX_OPERATIONS];

};

/* A mapping from the compressed opcode to the corresponding enum
   insn_code.  */
extern const enum insn_code tilegx_multiply_insn_seq_decode_opcode[];

/* Table mapping constant int multipliers to an expression
   tree that efficiently performs that multiplication.
   This is sorted by its 'multiplier' field so a binary search
   can look for matches.  */
extern const struct tilegx_multiply_insn_seq tilegx_multiply_insn_seq_table[];

/* The number of elements in multiply_insn_seq_table.  */
extern const int tilegx_multiply_insn_seq_table_size;

#endif /* !GCC_TILEGX_MULTIPLY_H */