| 1 | /* Declarations for caching. Typically used by remote back ends for |
| 2 | caching remote memory. |
| 3 | |
| 4 | Copyright 1992, 1993 Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
| 21 | |
| 22 | #ifndef DCACHE_H |
| 23 | #define DCACHE_H |
| 24 | |
| 25 | /* The data cache leads to incorrect results because it doesn't know about |
| 26 | volatile variables, thus making it impossible to debug functions which |
| 27 | use hardware registers. Therefore it is #if 0'd out. Effect on |
| 28 | performance is some, for backtraces of functions with a few |
| 29 | arguments each. For functions with many arguments, the stack |
| 30 | frames don't fit in the cache blocks, which makes the cache less |
| 31 | helpful. Disabling the cache is a big performance win for fetching |
| 32 | large structures, because the cache code fetched data in 16-byte |
| 33 | chunks. */ |
| 34 | |
| 35 | #define LINE_SIZE_POWER (4) |
| 36 | /* eg 1<<3 == 8 */ |
| 37 | #define LINE_SIZE (1 << LINE_SIZE_POWER) |
| 38 | /* Number of cache blocks */ |
| 39 | #define DCACHE_SIZE (64) |
| 40 | |
| 41 | struct dcache_block |
| 42 | { |
| 43 | struct dcache_block *next, *last; |
| 44 | unsigned int addr; /* Address for which data is recorded. */ |
| 45 | int data[LINE_SIZE / sizeof (int)]; |
| 46 | }; |
| 47 | |
| 48 | typedef int (*memxferfunc) PARAMS((CORE_ADDR memaddr, |
| 49 | unsigned char *myaddr, |
| 50 | int len)); |
| 51 | |
| 52 | typedef struct { |
| 53 | /* Function to actually read the target memory. */ |
| 54 | memxferfunc read_memory; |
| 55 | |
| 56 | /* Function to actually write the target memory */ |
| 57 | memxferfunc write_memory; |
| 58 | |
| 59 | /* free list */ |
| 60 | struct dcache_block dcache_free; |
| 61 | |
| 62 | /* in use list */ |
| 63 | struct dcache_block dcache_valid; |
| 64 | |
| 65 | /* The cache itself. */ |
| 66 | struct dcache_block *the_cache; |
| 67 | |
| 68 | } DCACHE; |
| 69 | |
| 70 | /* Using the data cache DCACHE return the contents of the word at |
| 71 | address ADDR in the remote machine. */ |
| 72 | int dcache_fetch PARAMS((DCACHE *dcache, CORE_ADDR addr)); |
| 73 | |
| 74 | /* Flush DCACHE. */ |
| 75 | void dcache_flush PARAMS((DCACHE *dcache)); |
| 76 | |
| 77 | /* Initialize DCACHE. */ |
| 78 | DCACHE *dcache_init PARAMS((memxferfunc reading, memxferfunc writing)); |
| 79 | |
| 80 | /* Write the word at ADDR both in the data cache and in the remote machine. */ |
| 81 | void dcache_poke PARAMS((DCACHE *dcache, CORE_ADDR addr, int data)); |
| 82 | |
| 83 | #endif /* DCACHE_H */ |