sim/common/sim-break.c

   1 /* Simulator breakpoint support.
   2    Copyright (C) 1997 Free Software Foundation, Inc.
   3    Contributed by Cygnus Support.
   4
   5 This file is part of GDB, the GNU debugger.
   6
   7 This program is free software; you can redistribute it and/or modify
   8 it under the terms of the GNU General Public License as published by
   9 the Free Software Foundation; either version 2, or (at your option)
  10 any later version.
  11
  12 This program is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License along
  18 with this program; if not, write to the Free Software Foundation, Inc.,
  19 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  20
  21 #include <stdio.h>
  22
  23 #include "sim-main.h"
  24 #include "sim-assert.h"
  25 #include "sim-break.h"
  26
  27 #ifndef SIM_BREAKPOINT
  28 #define SIM_BREAKPOINT {0x00}
  29 #define SIM_BREAKPOINT_SIZE (1)
  30 #endif
  31
  32 struct
  33 sim_breakpoint
  34 {
  35   struct sim_breakpoint *next;
  36   SIM_ADDR addr;                /* Address of this breakpoint */
  37   int flags;
  38   unsigned char loc_contents[SIM_BREAKPOINT_SIZE]; /* Contents of addr while
  39                                                       BP is enabled */
  40 };
  41
  42 #define SIM_BREAK_INSERTED 0x1  /* Breakpoint has been inserted */
  43 #define SIM_BREAK_DISABLED 0x2  /* Breakpoint is disabled */
  44
  45 static unsigned char sim_breakpoint [] = SIM_BREAKPOINT;
  46
  47 static void insert_breakpoint PARAMS ((SIM_DESC sd,
  48                                        struct sim_breakpoint *bp));
  49 static void remove_breakpoint PARAMS ((SIM_DESC sd,
  50                                        struct sim_breakpoint *bp));
  51 static SIM_RC resume_handler PARAMS ((SIM_DESC sd));
  52 static SIM_RC suspend_handler PARAMS ((SIM_DESC sd));
  53
  54
  55 /* Do the actual work of inserting a breakpoint into the instruction
  56    stream. */
  57
  58 static void
  59 insert_breakpoint (sd, bp)
  60      SIM_DESC sd;
  61      struct sim_breakpoint *bp;
  62 {
  63   if (bp->flags & (SIM_BREAK_INSERTED | SIM_BREAK_DISABLED))
  64     return;
  65
  66   sim_core_read_buffer (sd, NULL, exec_map, bp->loc_contents,
  67                         bp->addr, SIM_BREAKPOINT_SIZE);
  68   sim_core_write_buffer (sd, NULL, exec_map, sim_breakpoint,
  69                          bp->addr, SIM_BREAKPOINT_SIZE);
  70   bp->flags |= SIM_BREAK_INSERTED;
  71 }
  72
  73 /* Do the actual work of removing a breakpoint. */
  74
  75 static void
  76 remove_breakpoint (sd, bp)
  77      SIM_DESC sd;
  78      struct sim_breakpoint *bp;
  79 {
  80   if (!(bp->flags & SIM_BREAK_INSERTED))
  81     return;
  82
  83   sim_core_write_buffer (sd, NULL, exec_map, bp->loc_contents,
  84                          bp->addr, SIM_BREAKPOINT_SIZE);
  85   bp->flags &= ~SIM_BREAK_INSERTED;
  86 }
  87
  88 /* Come here when a breakpoint insn is hit.  If it's really a breakpoint, we
  89    halt things, and never return.  If it's a false hit, we return to let the
  90    caller handle things.  */
  91
  92 void
  93 sim_handle_breakpoint (sd, cpu, cia)
  94      SIM_DESC sd;
  95      sim_cpu *cpu;
  96      sim_cia cia;
  97 {
  98   struct sim_breakpoint *bp;
  99
 100   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 101     if (bp->addr == CIA_ADDR (cia))
 102       break;
 103
 104   if (!bp || !(bp->flags & SIM_BREAK_INSERTED))
 105     return;
 106
 107   sim_engine_halt (sd, STATE_CPU (sd, 0), NULL, cia, sim_stopped, SIM_SIGTRAP);
 108 }
 109
 110 /* Handler functions for simulator resume and suspend events. */
 111
 112 static SIM_RC
 113 resume_handler (sd)
 114      SIM_DESC sd;
 115 {
 116   struct sim_breakpoint *bp;
 117
 118   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 119     insert_breakpoint (sd, bp);
 120
 121   return SIM_RC_OK;
 122 }
 123
 124 static SIM_RC
 125 suspend_handler (sd)
 126      SIM_DESC sd;
 127 {
 128   struct sim_breakpoint *bp;
 129
 130   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 131     remove_breakpoint (sd, bp);
 132
 133   return SIM_RC_OK;
 134 }
 135
 136 /* Called from simulator module initialization.  */
 137
 138 SIM_RC
 139 sim_break_install (sd)
 140      SIM_DESC sd;
 141 {
 142   sim_module_add_resume_fn (sd, resume_handler);
 143   sim_module_add_suspend_fn (sd, suspend_handler);
 144
 145   return SIM_RC_OK;
 146 }
 147
 148 /* Install a breakpoint.  This is a user-function.  The breakpoint isn't
 149    actually installed here.  We just record it.  Resume_handler does the
 150    actual work.
 151 */
 152
 153 SIM_RC
 154 sim_set_breakpoint (sd, addr)
 155      SIM_DESC sd;
 156      SIM_ADDR addr;
 157 {
 158   struct sim_breakpoint *bp;
 159
 160   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 161     if (bp->addr == addr)
 162       return SIM_RC_DUPLICATE_BREAKPOINT; /* Already there */
 163     else
 164       break; /* FIXME: why not scan all bp's? */
 165
 166   bp = ZALLOC (struct sim_breakpoint);
 167
 168   bp->addr = addr;
 169   bp->next = STATE_BREAKPOINTS (sd);
 170   bp->flags = 0;
 171   STATE_BREAKPOINTS (sd) = bp;
 172
 173   return SIM_RC_OK;
 174 }
 175
 176 /* Delete a breakpoint.  All knowlege of the breakpoint is removed from the
 177    simulator.
 178 */
 179
 180 SIM_RC
 181 sim_clear_breakpoint (sd, addr)
 182      SIM_DESC sd;
 183      SIM_ADDR addr;
 184 {
 185   struct sim_breakpoint *bp, *bpprev;
 186
 187   for (bp = STATE_BREAKPOINTS (sd), bpprev = NULL;
 188        bp;
 189        bpprev = bp, bp = bp->next)
 190     if (bp->addr == addr)
 191       break;
 192
 193   if (!bp)
 194     return SIM_RC_UNKNOWN_BREAKPOINT;
 195
 196   remove_breakpoint (sd, bp);
 197
 198   if (bpprev)
 199     bpprev->next = bp->next;
 200   else
 201     STATE_BREAKPOINTS (sd) = NULL;
 202
 203   zfree (bp);
 204
 205   return SIM_RC_OK;
 206 }
 207
 208 SIM_RC
 209 sim_clear_all_breakpoints (sd)
 210      SIM_DESC sd;
 211 {
 212   while (STATE_BREAKPOINTS (sd))
 213     sim_clear_breakpoint (sd, STATE_BREAKPOINTS (sd)->addr);
 214
 215   return SIM_RC_OK;
 216 }
 217
 218 SIM_RC
 219 sim_enable_breakpoint (sd, addr)
 220      SIM_DESC sd;
 221      SIM_ADDR addr;
 222 {
 223   struct sim_breakpoint *bp;
 224
 225   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 226     if (bp->addr == addr)
 227       break;
 228
 229   if (!bp)
 230     return SIM_RC_UNKNOWN_BREAKPOINT;
 231
 232   bp->flags &= ~SIM_BREAK_DISABLED;
 233
 234   return SIM_RC_OK;
 235 }
 236
 237 SIM_RC
 238 sim_disable_breakpoint (sd, addr)
 239      SIM_DESC sd;
 240      SIM_ADDR addr;
 241 {
 242   struct sim_breakpoint *bp;
 243
 244   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 245     if (bp->addr == addr)
 246       break;
 247
 248   if (!bp)
 249     return SIM_RC_UNKNOWN_BREAKPOINT;
 250
 251   bp->flags |= SIM_BREAK_DISABLED;
 252
 253   return SIM_RC_OK;
 254 }
 255
 256 SIM_RC
 257 sim_enable_all_breakpoints (sd)
 258      SIM_DESC sd;
 259 {
 260   struct sim_breakpoint *bp;
 261
 262   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 263     bp->flags &= ~SIM_BREAK_DISABLED;
 264
 265   return SIM_RC_OK;
 266 }
 267
 268 SIM_RC
 269 sim_disable_all_breakpoints (sd)
 270      SIM_DESC sd;
 271 {
 272   struct sim_breakpoint *bp;
 273
 274   for (bp = STATE_BREAKPOINTS (sd); bp; bp = bp->next)
 275     bp->flags |= SIM_BREAK_DISABLED;
 276
 277   return SIM_RC_OK;
 278 }