projects / deliverable / binutils-gdb.git / blame
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| c906108c SS |
1 | /* This file is part of the program psim. |
| 2 | ||
| 3 | Copyright (C) 1994-1995, 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 | ||
| 22 | /* Creates the files semantics.[hc]. | |
| 23 | ||
| 24 | The generated file semantics contains functions that implement the | |
| 25 | operations required to model a single target processor instruction. | |
| 26 | ||
| 27 | Several different variations on the semantics file can be created: | |
| 28 | ||
| 29 | o uncached | |
| 30 | ||
| 31 | No instruction cache exists. The semantic function | |
| 32 | needs to generate any required values locally. | |
| 33 | ||
| 34 | o cached - separate cracker and semantic | |
| 35 | ||
| 36 | Two independant functions are created. Firstly the | |
| 37 | function that cracks an instruction entering it into a | |
| 38 | cache and secondly the semantic function propper that | |
| 39 | uses the cache. | |
| 40 | ||
| 41 | o cached - semantic + cracking semantic | |
| 42 | ||
| 43 | The function that cracks the instruction and enters | |
| 44 | all values into the cache also contains a copy of the | |
| 45 | semantic code (avoiding the need to call both the | |
| 46 | cracker and the semantic function when there is a | |
| 47 | cache miss). | |
| 48 | ||
| 49 | For each of these general forms, several refinements can occure: | |
| 50 | ||
| 51 | o do/don't duplicate/expand semantic functions | |
| 52 | ||
| 53 | As a consequence of decoding an instruction, the | |
| 54 | decoder, as part of its table may have effectivly made | |
| 55 | certain of the variable fields in an instruction | |
| 56 | constant. Separate functions for each of the | |
| 57 | alternative values for what would have been treated as | |
| 58 | a variable part can be created. | |
| 59 | ||
| 60 | o use cache struct directly. | |
| 61 | ||
| 62 | When a cracking cache is present, the semantic | |
| 63 | functions can be generated to either hold intermediate | |
| 64 | cache values in local variables or always refer to the | |
| 65 | contents of the cache directly. */ | |
| 66 | ||
| 67 | ||
| 68 | ||
| 69 | extern insn_handler print_semantic_declaration; | |
| 70 | extern insn_handler print_semantic_definition; | |
| 71 | ||
| 72 | extern void print_idecode_illegal | |
| 73 | (lf *file, | |
| 74 | const char *result); | |
| 75 | ||
| 76 | extern void print_semantic_body | |
| 77 | (lf *file, | |
| 78 | insn *instruction, | |
| 79 | insn_bits *expanded_bits, | |
| 80 | opcode_field *opcodes); | |
| 81 |