sim/ppc/ld-cache.h

   1 /*  This file is part of the program psim.
   2
   3     Copyright (C) 1994-1997, Andrew Cagney <cagney@highland.com.au>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 2 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, write to the Free Software
  17     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18
  19     */
  20
  21 /* Instruction unpacking:
  22
  23    Once the instruction has been decoded, the register (and other)
  24    fields within the instruction need to be extracted.
  25
  26    The table that follows determines how each field should be treated.
  27    Importantly it considers the case where the extracted field is to
  28    be used immediatly or stored in an instruction cache.
  29
  30    <type>
  31
  32    Indicates what to do with the cache entry.  If a cache is to be
  33    used.  SCRATCH and CACHE values are defined when a cache entry is
  34    being filled while CACHE and COMPUTE values are defined in the
  35    semantic code.
  36
  37    Zero marks the end of the table.  More importantly 1. indicates
  38    that the entry is valid and can be cached. 2. indicates that that
  39    the entry is valid but can not be cached.
  40
  41    <field_name>
  42
  43    The field name as given in the instruction spec.
  44
  45    <derived_name>
  46
  47    A new name for <field_name> once it has been extracted from the
  48    instruction (and possibly stored in the instruction cache).
  49
  50    <type>
  51
  52    String specifying the storage type for <new_name> (the extracted
  53    field>.
  54
  55    <expression>
  56
  57    Specifies how to get <new_name> from <old_name>.  If null, old and
  58    new name had better be the same. */
  59
  60
  61 typedef enum {
  62   scratch_value,
  63   cache_value,
  64   compute_value,
  65 } cache_rule_type;
  66
  67 typedef struct _cache_table cache_table;
  68 struct _cache_table {
  69   cache_rule_type type;
  70   char *field_name;
  71   char *derived_name;
  72   char *type_def;
  73   char *expression;
  74   table_entry *file_entry;
  75   cache_table *next;
  76 };
  77
  78
  79 extern cache_table *load_cache_table
  80 (char *file_name,
  81  int hi_bit_nr);