cecc0aa9f9
single stepping of multiple instructions (e.g., s/p,<count> and n/p). db_print_loc_and_inst() already prints a newline on all arches although it probably shouldn't. Especially on SMP systems, single stepping tends to deadlock or panic too quickly to be useful for anything except finding bugs in itself, but with printing "itself" includes console drivers so it is useful for generating stress tests for console drivers.
385 lines
8.4 KiB
C
385 lines
8.4 KiB
C
/*-
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* Mach Operating System
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* Copyright (c) 1991,1990 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/*
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* Author: David B. Golub, Carnegie Mellon University
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* Date: 7/90
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*/
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/*
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* Commands to run process.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kdb.h>
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#include <sys/proc.h>
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#include <machine/kdb.h>
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#include <machine/pcb.h>
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#include <vm/vm.h>
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#include <ddb/ddb.h>
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#include <ddb/db_break.h>
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#include <ddb/db_access.h>
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static int db_run_mode;
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#define STEP_NONE 0
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#define STEP_ONCE 1
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#define STEP_RETURN 2
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#define STEP_CALLT 3
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#define STEP_CONTINUE 4
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#define STEP_INVISIBLE 5
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#define STEP_COUNT 6
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static bool db_sstep_print;
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static int db_loop_count;
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static int db_call_depth;
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int db_inst_count;
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int db_load_count;
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int db_store_count;
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#ifdef SOFTWARE_SSTEP
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db_breakpoint_t db_not_taken_bkpt = 0;
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db_breakpoint_t db_taken_bkpt = 0;
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#endif
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#ifndef db_set_single_step
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void db_set_single_step(void);
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#endif
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#ifndef db_clear_single_step
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void db_clear_single_step(void);
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#endif
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#ifndef db_pc_is_singlestep
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static bool
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db_pc_is_singlestep(db_addr_t pc)
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{
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#ifdef SOFTWARE_SSTEP
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if ((db_not_taken_bkpt != 0 && pc == db_not_taken_bkpt->address)
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|| (db_taken_bkpt != 0 && pc == db_taken_bkpt->address))
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return (true);
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#endif
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return (false);
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}
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#endif
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bool
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db_stop_at_pc(bool *is_breakpoint)
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{
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db_addr_t pc;
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db_breakpoint_t bkpt;
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pc = PC_REGS();
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if (db_pc_is_singlestep(pc))
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*is_breakpoint = false;
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db_clear_single_step();
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db_clear_breakpoints();
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db_clear_watchpoints();
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#ifdef FIXUP_PC_AFTER_BREAK
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if (*is_breakpoint) {
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/*
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* Breakpoint trap. Fix up the PC if the
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* machine requires it.
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*/
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FIXUP_PC_AFTER_BREAK
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pc = PC_REGS();
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}
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#endif
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/*
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* Now check for a breakpoint at this address.
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*/
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bkpt = db_find_breakpoint_here(pc);
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if (bkpt) {
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if (--bkpt->count == 0) {
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bkpt->count = bkpt->init_count;
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*is_breakpoint = true;
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return (true); /* stop here */
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}
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} else if (*is_breakpoint) {
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#ifdef BKPT_SKIP
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BKPT_SKIP;
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#endif
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}
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*is_breakpoint = false;
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if (db_run_mode == STEP_INVISIBLE) {
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db_run_mode = STEP_CONTINUE;
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return (false); /* continue */
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}
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if (db_run_mode == STEP_COUNT) {
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return (false); /* continue */
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}
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if (db_run_mode == STEP_ONCE) {
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if (--db_loop_count > 0) {
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if (db_sstep_print) {
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db_printf("\t\t");
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db_print_loc_and_inst(pc);
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}
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return (false); /* continue */
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}
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}
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if (db_run_mode == STEP_RETURN) {
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/* continue until matching return */
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db_expr_t ins;
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ins = db_get_value(pc, sizeof(int), false);
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if (!inst_trap_return(ins) &&
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(!inst_return(ins) || --db_call_depth != 0)) {
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if (db_sstep_print) {
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if (inst_call(ins) || inst_return(ins)) {
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int i;
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db_printf("[after %6d] ", db_inst_count);
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for (i = db_call_depth; --i > 0; )
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db_printf(" ");
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db_print_loc_and_inst(pc);
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}
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}
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if (inst_call(ins))
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db_call_depth++;
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return (false); /* continue */
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}
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}
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if (db_run_mode == STEP_CALLT) {
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/* continue until call or return */
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db_expr_t ins;
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ins = db_get_value(pc, sizeof(int), false);
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if (!inst_call(ins) &&
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!inst_return(ins) &&
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!inst_trap_return(ins)) {
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return (false); /* continue */
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}
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}
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db_run_mode = STEP_NONE;
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return (true);
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}
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void
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db_restart_at_pc(bool watchpt)
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{
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db_addr_t pc = PC_REGS();
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if ((db_run_mode == STEP_COUNT) ||
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(db_run_mode == STEP_RETURN) ||
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(db_run_mode == STEP_CALLT)) {
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/*
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* We are about to execute this instruction,
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* so count it now.
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*/
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#ifdef SOFTWARE_SSTEP
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db_expr_t ins =
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#endif
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db_get_value(pc, sizeof(int), false);
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db_inst_count++;
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db_load_count += inst_load(ins);
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db_store_count += inst_store(ins);
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#ifdef SOFTWARE_SSTEP
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/* XXX works on mips, but... */
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if (inst_branch(ins) || inst_call(ins)) {
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ins = db_get_value(next_instr_address(pc,1),
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sizeof(int), false);
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db_inst_count++;
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db_load_count += inst_load(ins);
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db_store_count += inst_store(ins);
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}
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#endif /* SOFTWARE_SSTEP */
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}
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if (db_run_mode == STEP_CONTINUE) {
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if (watchpt || db_find_breakpoint_here(pc)) {
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/*
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* Step over breakpoint/watchpoint.
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*/
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db_run_mode = STEP_INVISIBLE;
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db_set_single_step();
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} else {
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db_set_breakpoints();
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db_set_watchpoints();
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}
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} else {
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db_set_single_step();
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}
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}
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#ifdef SOFTWARE_SSTEP
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/*
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* Software implementation of single-stepping.
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* If your machine does not have a trace mode
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* similar to the vax or sun ones you can use
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* this implementation, done for the mips.
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* Just define the above conditional and provide
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* the functions/macros defined below.
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*
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* extern bool
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* inst_branch(), returns true if the instruction might branch
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* extern unsigned
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* branch_taken(), return the address the instruction might
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* branch to
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* db_getreg_val(); return the value of a user register,
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* as indicated in the hardware instruction
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* encoding, e.g. 8 for r8
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*
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* next_instr_address(pc,bd) returns the address of the first
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* instruction following the one at "pc",
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* which is either in the taken path of
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* the branch (bd==1) or not. This is
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* for machines (mips) with branch delays.
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*
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* A single-step may involve at most 2 breakpoints -
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* one for branch-not-taken and one for branch taken.
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* If one of these addresses does not already have a breakpoint,
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* we allocate a breakpoint and save it here.
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* These breakpoints are deleted on return.
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*/
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void
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db_set_single_step(void)
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{
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db_addr_t pc = PC_REGS(), brpc;
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unsigned inst;
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/*
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* User was stopped at pc, e.g. the instruction
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* at pc was not executed.
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*/
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inst = db_get_value(pc, sizeof(int), false);
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if (inst_branch(inst) || inst_call(inst) || inst_return(inst)) {
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brpc = branch_taken(inst, pc);
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if (brpc != pc) { /* self-branches are hopeless */
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db_taken_bkpt = db_set_temp_breakpoint(brpc);
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}
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pc = next_instr_address(pc, 1);
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}
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pc = next_instr_address(pc, 0);
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db_not_taken_bkpt = db_set_temp_breakpoint(pc);
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}
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void
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db_clear_single_step(void)
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{
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if (db_not_taken_bkpt != 0) {
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db_delete_temp_breakpoint(db_not_taken_bkpt);
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db_not_taken_bkpt = 0;
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}
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if (db_taken_bkpt != 0) {
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db_delete_temp_breakpoint(db_taken_bkpt);
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db_taken_bkpt = 0;
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}
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}
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#endif /* SOFTWARE_SSTEP */
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extern int db_cmd_loop_done;
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/* single-step */
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/*ARGSUSED*/
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void
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db_single_step_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
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{
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bool print = false;
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if (count == -1)
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count = 1;
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if (modif[0] == 'p')
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print = true;
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db_run_mode = STEP_ONCE;
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db_loop_count = count;
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db_sstep_print = print;
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db_inst_count = 0;
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db_load_count = 0;
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db_store_count = 0;
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db_cmd_loop_done = 1;
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}
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/* trace and print until call/return */
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/*ARGSUSED*/
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void
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db_trace_until_call_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
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char *modif)
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{
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bool print = false;
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if (modif[0] == 'p')
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print = true;
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db_run_mode = STEP_CALLT;
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db_sstep_print = print;
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db_inst_count = 0;
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db_load_count = 0;
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db_store_count = 0;
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db_cmd_loop_done = 1;
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}
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/*ARGSUSED*/
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void
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db_trace_until_matching_cmd(db_expr_t addr, bool have_addr, db_expr_t count,
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char *modif)
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{
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bool print = false;
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if (modif[0] == 'p')
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print = true;
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db_run_mode = STEP_RETURN;
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db_call_depth = 1;
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db_sstep_print = print;
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db_inst_count = 0;
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db_load_count = 0;
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db_store_count = 0;
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db_cmd_loop_done = 1;
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}
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/* continue */
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/*ARGSUSED*/
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void
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db_continue_cmd(db_expr_t addr, bool have_addr, db_expr_t count, char *modif)
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{
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if (modif[0] == 'c')
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db_run_mode = STEP_COUNT;
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else
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db_run_mode = STEP_CONTINUE;
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db_inst_count = 0;
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db_load_count = 0;
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db_store_count = 0;
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db_cmd_loop_done = 1;
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}
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