0.3.2/src/debugger.c

/*
 *  Copyright (C) 2003-2005  Anders Gavare.  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright  
 *     notice, this list of conditions and the following disclaimer in the 
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE   
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 *
 *
 *  $Id: debugger.c,v 1.101 2005/04/18 21:41:19 debug Exp $
 *
 *  Single-step debugger.
 *
 *
 *  TODO:
 *
 *      This entire module is very much non-reentrant. :-/
 *
 *      Add more functionality that already exists elsewhere in the emulator.
 *
 *      More generic expression evaluator (for example + - * / between multiple
 *      terms), including _TAB COMPLETION_ of symbols and register names!
 *
 *      Nicer looking output of register dumps, floating point registers,
 *      etc. Warn about weird/invalid register contents.
 *
 *      Ctrl-C doesn't enter the debugger on some OSes (HP-UX?)...
 *
 *      Many other TODOs.
 */

#include <ctype.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "bintrans.h"
#include "console.h"
#include "cpu.h"
#include "device.h"
#include "debugger.h"
#include "diskimage.h"
#include "emul.h"
#include "machine.h"
#include "memory.h"
#include "misc.h"
#include "net.h"
#include "x11.h"


extern int extra_argc;
extern char **extra_argv;

extern int quiet_mode;


/*
 *  Global debugger variables:
 */

volatile int single_step = 0;
int force_debugger_at_exit = 0;
int show_opcode_statistics = 0;

int old_instruction_trace = 0;
int old_quiet_mode = 0;
int old_show_trace_tree = 0;


/*
 *  Private (global) debugger variables:
 */

static volatile int ctrl_c;

static int debugger_n_emuls;
static struct emul **debugger_emuls;
static struct emul *debugger_emul;
static struct machine *debugger_machine;

static int exit_debugger;
static int n_steps_left_before_interaction = 0;

#define MAX_CMD_LEN             70
#define N_PREVIOUS_CMDS         150
static char *last_cmd[N_PREVIOUS_CMDS];
static int last_cmd_index;

static char repeat_cmd[MAX_CMD_LEN + 1];

#define MAGIC_UNTOUCHED         0x98ca76c2ffcc0011ULL

static uint64_t last_dump_addr = MAGIC_UNTOUCHED;
static uint64_t last_unasm_addr = MAGIC_UNTOUCHED;


/*
 *  debugger_activate():
 *
 *  This is a signal handler for CTRL-C.  It shouldn't be called directly,
 *  but setup code in emul.c sets the CTRL-C signal handler to use this
 *  function.
 */
void debugger_activate(int x)
{
        ctrl_c = 1;

        if (single_step) {
                /*  Already in the debugger. Do nothing.  */
                int i;
                for (i=0; i<MAX_CMD_LEN+1; i++)
                        console_makeavail(MAIN_CONSOLE, '\b');
                console_makeavail(MAIN_CONSOLE, ' ');
                console_makeavail(MAIN_CONSOLE, '\n');
                printf("^C");
                fflush(stdout);
        } else {
                /*  Enter the single step debugger.  */
                single_step = 1;

                /*  Discard any chars in the input queue:  */
                while (console_charavail(MAIN_CONSOLE))
                        console_readchar(MAIN_CONSOLE);
        }

        /*  Clear the repeat-command buffer:  */
        repeat_cmd[0] = '\0';

        /*  Reactivate the signal handler:  */
        signal(SIGINT, debugger_activate);
}


/*
 *  debugger_parse_name():
 *
 *  This function reads a string, and tries to match it to a register name,
 *  a symbol, or treat it as a decimal numeric value.
 *
 *  Some examples:
 *
 *      "0x7fff1234"            ==> numeric value (hex, in this case)
 *      "pc", "r5", "hi", "t4"  ==> register (CPU dependant)
 *      "memcpy+64"             ==> symbol (plus offset)
 *
 *  Register names can be preceeded by "x:" where x is the CPU number. (CPU
 *  0 is assumed by default.)
 *
 *  To force detection of different types, a character can be added in front of
 *  the name: "$" for numeric values, "%" for registers, and "@" for symbols.
 *
 *  Return value is:
 *
 *      NAME_PARSE_NOMATCH      no match
 *      NAME_PARSE_MULTIPLE     multiple matches
 *
 *  or one of these (and then *valuep is read or written, depending on
 *  the writeflag):
 *
 *      NAME_PARSE_REGISTER     a register
 *      NAME_PARSE_NUMBER       a hex number
 *      NAME_PARSE_SYMBOL       a symbol
 */
#define NAME_PARSE_NOMATCH      0
#define NAME_PARSE_MULTIPLE     1
#define NAME_PARSE_REGISTER     2
#define NAME_PARSE_NUMBER       3
#define NAME_PARSE_SYMBOL       4
static int debugger_parse_name(struct machine *m, char *name, int writeflag,
        uint64_t *valuep)
{
        int match_register = 0, match_symbol = 0, match_numeric = 0;
        int skip_register, skip_numeric, skip_symbol;

        if (m == NULL || name == NULL) {
                fprintf(stderr, "debugger_parse_name(): NULL ptr\n");
                exit(1);
        }

        /*  Warn about non-signextended values:  */
        if (writeflag &&
            ((*valuep) >> 32) == 0 && (*valuep) & 0x80000000ULL)
                printf("WARNING: The value is not sign-extended. "
                    "Is this what you intended?\n");

        skip_register = name[0] == '$' || name[0] == '@';
        skip_numeric  = name[0] == '%' || name[0] == '@';
        skip_symbol   = name[0] == '$' || name[0] == '%';

        /*  Check for a register match:  */
        if (!skip_register && strlen(name) >= 1)
                cpu_register_match(m, name, writeflag, valuep,
                    &match_register);

        /*  Check for a number match:  */
        if (!skip_numeric && isdigit((int)name[0])) {
                uint64_t x;
                x = strtoull(name, NULL, 0);
                if (writeflag) {
                        printf("You cannot assign like that.\n");
                } else
                        *valuep = x;
                match_numeric = 1;
        }

        /*  Check for a symbol match:  */
        if (!skip_symbol) {
                int res;
                char *p, *sn;
                uint64_t newaddr, ofs = 0;

                sn = malloc(strlen(name) + 1);
                if (sn == NULL) {
                        fprintf(stderr, "out of memory in debugger\n");
                        exit(1);
                }
                strcpy(sn, name);

                /*  Is there a '+' in there? Then treat that as an offset:  */
                p = strchr(sn, '+');
                if (p != NULL) {
                        *p = '\0';
                        ofs = strtoull(p+1, NULL, 0);
                }

                res = get_symbol_addr(&m->symbol_context, sn, &newaddr);
                if (res) {
                        if (writeflag) {
                                printf("You cannot assign like that.\n");
                        } else
                                *valuep = newaddr + ofs;
                        match_symbol = 1;
                }

                free(sn);
        }

        if (match_register + match_symbol + match_numeric > 1)
                return NAME_PARSE_MULTIPLE;

        if (match_register)
                return NAME_PARSE_REGISTER;
        if (match_numeric)
                return NAME_PARSE_NUMBER;
        if (match_symbol)
                return NAME_PARSE_SYMBOL;

        return NAME_PARSE_NOMATCH;
}


/*
 *  show_breakpoint():
 */
static void show_breakpoint(struct machine *m, int i)
{
        printf("%3i: 0x%016llx", i,
            (long long)m->breakpoint_addr[i]);
        if (m->breakpoint_string[i] != NULL)
                printf(" (%s)", m->breakpoint_string[i]);
        if (m->breakpoint_flags[i])
                printf(": flags=0x%x", m->breakpoint_flags[i]);
        printf("\n");
}


/****************************************************************************/


/*
 *  debugger_cmd_breakpoint():
 *
 *  TODO: automagic "expansion" for the subcommand names (s => show).
 */
static void debugger_cmd_breakpoint(struct machine *m, char *cmd_line)
{
        int i, res;

        while (cmd_line[0] != '\0' && cmd_line[0] == ' ')
                cmd_line ++;

        if (cmd_line[0] == '\0') {
                printf("syntax: breakpoint subcmd [args...]\n");
                printf("Available subcmds (and args) are:\n");
                printf("  add addr      add a breakpoint for address addr\n");
                printf("  delete x      delete breakpoint nr x\n");
                printf("  show          show current breakpoints\n");
                return;
        }

        if (strcmp(cmd_line, "show") == 0) {
                if (m->n_breakpoints == 0)
                        printf("No breakpoints set.\n");
                for (i=0; i<m->n_breakpoints; i++)
                        show_breakpoint(m, i);
                return;
        }

        if (strncmp(cmd_line, "delete ", 7) == 0) {
                int x = atoi(cmd_line + 7);

                if (m->n_breakpoints == 0) {
                        printf("No breakpoints set.\n");
                        return;
                }
                if (x < 0 || x >= m->n_breakpoints) {
                        printf("Invalid breakpoint nr %i. Use 'breakpoint "
                            "show' to see the current breakpoints.\n", x);
                        return;
                }

                free(m->breakpoint_string[x]);

                for (i=x; i<m->n_breakpoints-1; i++) {
                        m->breakpoint_addr[i]   = m->breakpoint_addr[i+1];
                        m->breakpoint_string[i] = m->breakpoint_string[i+1];
                        m->breakpoint_flags[i]  = m->breakpoint_flags[i+1];
                }
                m->n_breakpoints --;
                return;
        }

        if (strncmp(cmd_line, "add ", 4) == 0) {
                uint64_t tmp;

                if (m->n_breakpoints >= MAX_BREAKPOINTS) {
                        printf("Too many breakpoints. (You need to recompile"
                            " gxemul to increase this. Max = %i.)\n",
                            MAX_BREAKPOINTS);
                        return;
                }

                i = m->n_breakpoints;

                res = debugger_parse_name(m, cmd_line + 4, 0, &tmp);
                if (!res) {
                        printf("Couldn't parse '%s'\n", cmd_line + 4);
                        return;
                }

                m->breakpoint_string[i] = malloc(strlen(cmd_line+4) + 1);
                if (m->breakpoint_string[i] == NULL) {
                        printf("out of memory in debugger_cmd_breakpoint()\n");
                        exit(1);
                }
                strcpy(m->breakpoint_string[i], cmd_line+4);
                m->breakpoint_addr[i] = tmp;
                m->breakpoint_flags[i] = 0;

                m->n_breakpoints ++;
                show_breakpoint(m, i);
                return;
        }

        printf("Unknown breakpoint subcommand.\n");
}


/*
 *  debugger_cmd_bintrans():
 */
static void debugger_cmd_bintrans(struct machine *m, char *cmd_line)
{
        int i;

        if (*cmd_line == '\0')
                goto printstate;

        if (!m->bintrans_enabled_from_start) {
                printf("You must have enabled bintrans from the start of the "
                    "simulation.\nIt is not possible to turn on afterwards.\n");
                return;
        }

        while (*cmd_line == ' ')
                cmd_line++;

        /*  Note: len 3 and 4, to include the NUL char.  */
        if (strncasecmp(cmd_line, "on", 3) == 0) {
                m->bintrans_enable = 1;
                for (i=0; i<m->ncpus; i++)
                        bintrans_restart(m->cpus[i]);
        } else if (strncasecmp(cmd_line, "off", 4) == 0)
                m->bintrans_enable = 0;
        else
                printf("syntax: bintrans [on|off]\n");

printstate:
        printf("bintrans is now %s%s\n",
             m->bintrans_enable? "ENABLED" : "disabled",
             m->old_bintrans_enable? " (using the OLD bintrans system)" : "");
}


/*
 *  debugger_cmd_continue():
 */
static void debugger_cmd_continue(struct machine *m, char *cmd_line)
{
        if (*cmd_line) {
                printf("syntax: continue\n");
                return;
        }

        exit_debugger = 1;
}


/*
 *  debugger_cmd_device():
 */
static void debugger_cmd_device(struct machine *m, char *cmd_line)
{
        int i, j;
        struct memory *mem;
        struct cpu *c;

        if (cmd_line[0] == '\0')
                goto return_help;

        if (m->cpus == NULL) {
                printf("No cpus (?)\n");
                return;
        }
        c = m->cpus[m->bootstrap_cpu];
        if (c == NULL) {
                printf("m->cpus[m->bootstrap_cpu] = NULL\n");
                return;
        }
        mem = m->cpus[m->bootstrap_cpu]->mem;

        if (m->cpus == NULL) {
                printf("No cpus (?)\n");
                return;
        }
        c = m->cpus[m->bootstrap_cpu];
        if (c == NULL) {
                printf("m->cpus[m->bootstrap_cpu] = NULL\n");
                return;
        }
        mem = m->cpus[m->bootstrap_cpu]->mem;

        if (strcmp(cmd_line, "all") == 0) {
                device_dumplist();
        } else if (strncmp(cmd_line, "add ", 4) == 0) {
                device_add(m, cmd_line+4);
        } else if (strncmp(cmd_line, "remove ", 7) == 0) {
                i = atoi(cmd_line + 7);
                if (i==0 && cmd_line[7]!='0') {
                        printf("Weird device number. Use 'device list'.\n");
                } else
                        memory_device_remove(m->memory, i);
        } else if (strncmp(cmd_line, "state ", 6) == 0) {
                i = atoi(cmd_line + 6);
                if (i < 0 || i >= mem->n_mmapped_devices) {
                        printf("No devices with that id.\n");
                        return;
                }

                if (mem->dev_f_state[i] == NULL) {
                        printf("No state function has been implemented yet "
                            "for that device type.\n");
                        return;
                }

                for (j=0; ; j++) {
                        int type;
                        char *name;
                        void *data;
                        size_t len;
                        int res = mem->dev_f_state[i](c, mem,
                            mem->dev_extra[i], 0, j, &type, &name, &data, &len);
                        if (!res)
                                break;
                        printf("%2i:%30s = (", j, name);
                        switch (type) {
                        case DEVICE_STATE_TYPE_INT:
                                printf("int) %i", *((int *)data));
                                break;
                        default:
                                printf("unknown)");
                        }
                        printf("\n");
                }
        } else if (strcmp(cmd_line, "list") == 0) {
                if (mem->n_mmapped_devices == 0)
                        printf("No memory-mapped devices in this machine.\n");

                for (i=0; i<mem->n_mmapped_devices; i++) {
                        printf("%2i: %25s @ 0x%011llx, len = 0x%llx",
                            i, mem->dev_name[i],
                            (long long)mem->dev_baseaddr[i],
                            (long long)mem->dev_length[i]);
                        if (mem->dev_flags[i]) {
                                printf(" (");
                                if (mem->dev_flags[i] & MEM_BINTRANS_OK)
                                        printf("BINTRANS R");
                                if (mem->dev_flags[i] & MEM_BINTRANS_WRITE_OK)
                                        printf("+W");
                                printf(")");
                        }
                        printf("\n");
                }
        } else
                goto return_help;

        return;

return_help:
        printf("syntax: devices cmd [...]\n");
        printf("Available cmds are:\n");
        printf("  add name_and_params    add a device to the current "
            "machine\n");
        printf("  all                    list all registered devices\n");
        printf("  list                   list memory-mapped devices in the"
            " current machine\n");
        printf("  remove x               remove device nr x from the "
            "current machine\n");
        printf("  state x                show state of device nr x in"
            " the current machine\n");
}


/*
 *  debugger_cmd_dump():
 *
 *  Dump emulated memory in hex and ASCII.
 *
 *  syntax: dump [addr [endaddr]]
 */
static void debugger_cmd_dump(struct machine *m, char *cmd_line)
{
        uint64_t addr, addr_start, addr_end;
        struct cpu *c;
        struct memory *mem;
        char *p = NULL;
        int x, r;

        if (cmd_line[0] != '\0') {
                uint64_t tmp;
                char *tmps = strdup(cmd_line);

                /*  addr:  */
                p = strchr(tmps, ' ');
                if (p != NULL)
                        *p = '\0';
                r = debugger_parse_name(m, tmps, 0, &tmp);
                free(tmps);

                if (r == NAME_PARSE_NOMATCH || r == NAME_PARSE_MULTIPLE) {
                        printf("Unparsable address: %s\n", cmd_line);
                        return;
                } else {
                        last_dump_addr = tmp;
                }

                p = strchr(cmd_line, ' ');
        }

        addr_start = last_dump_addr;

        if (addr_start == MAGIC_UNTOUCHED) {
                uint64_t tmp;
                int match_register = 0;
                cpu_register_match(m, "pc", 0, &tmp, &match_register);
                if (match_register) {
                        addr_start = tmp;
                } else {
                        printf("No starting address.\n");
                        return;
                }
        }

        addr_end = addr_start + 16 * 16;

        /*  endaddr:  */
        if (p != NULL) {
                while (*p == ' ' && *p)
                        p++;
                r = debugger_parse_name(m, p, 0, &addr_end);
                if (r == NAME_PARSE_NOMATCH || r == NAME_PARSE_MULTIPLE) {
                        printf("Unparsable address: %s\n", cmd_line);
                        return;
                }
        }

        if (m->cpus == NULL) {
                printf("No cpus (?)\n");
                return;
        }
        c = m->cpus[m->bootstrap_cpu];
        if (c == NULL) {
                printf("m->cpus[m->bootstrap_cpu] = NULL\n");
                return;
        }
        mem = m->cpus[m->bootstrap_cpu]->mem;

        addr = addr_start & ~0xf;

        ctrl_c = 0;

        while (addr < addr_end) {
                unsigned char buf[16];
                memset(buf, 0, sizeof(buf));
                r = c->memory_rw(c, mem, addr, &buf[0], sizeof(buf),
                    MEM_READ, CACHE_NONE | NO_EXCEPTIONS);

                printf("0x%016llx  ", (long long)addr);

                if (r == MEMORY_ACCESS_FAILED)
                        printf("(memory access failed)\n");
                else {
                        for (x=0; x<16; x++) {
                                if (addr + x >= addr_start &&
                                    addr + x < addr_end)
                                        printf("%02x%s", buf[x],
                                            (x&3)==3? " " : "");
                                else
                                        printf("  %s", (x&3)==3? " " : "");
                        }
                        printf(" ");
                        for (x=0; x<16; x++) {
                                if (addr + x >= addr_start &&
                                    addr + x < addr_end)
                                        printf("%c", (buf[x]>=' ' &&
                                            buf[x]<127)? buf[x] : '.');
                                else
                                        printf(" ");
                        }
                        printf("\n");
                }

                if (ctrl_c)
                        return;

                addr += sizeof(buf);
        }

        last_dump_addr = addr_end;

        strcpy(repeat_cmd, "dump");
}


/*
 *  debugger_cmd_emuls():
 *
 *  Dump info about all current emuls.
 */
static void debugger_cmd_emuls(struct machine *m, char *cmd_line)
{
        int i, iadd = 4;

        if (*cmd_line) {
                printf("syntax: emuls\n");
                return;
        }

        for (i=0; i<debugger_n_emuls; i++) {
                struct emul *e = debugger_emuls[i];

                if (e == NULL)
                        continue;

                debug("emulation %i: \"%s\"\n", i,
                    e->name == NULL? "(no name)" : e->name);
                debug_indentation(iadd);

                emul_dumpinfo(e);

                debug_indentation(-iadd);
        }
}


/*
 *  debugger_cmd_focus():
 *
 *  Changes focus to specific machine (in a specific emulation).
 */
static void debugger_cmd_focus(struct machine *m, char *cmd_line)
{
        int x = -1, y = -1;
        char *p;

        if (!cmd_line[0]) {
                printf("syntax: focus x[,y]\n");
                printf("where x and y are integers as reported by the"
                    " 'emuls' command\n");
                goto print_current_focus_and_return;
        }

        x = atoi(cmd_line);
        p = strchr(cmd_line, ',');
        if (p == cmd_line) {
                printf("No machine number specified?\n");
                printf("syntax: focus x[,y]\n");
                return;
        }

        if (p != NULL)
                y = atoi(p + 1);

        if (y != -1) {
                /*  Change emul:  */
                if (y < 0 || y >= debugger_n_emuls) {
                        printf("Invalid emul number: %i\n", y);
                        return;
                }

                debugger_emul = debugger_emuls[y];

                /*  This is just in case the machine change below fails...  */
                debugger_machine = debugger_emul->machines[0];
        }

        /*  Change machine:  */
        if (x < 0 || x >= debugger_emul->n_machines) {
                printf("Invalid machine number: %i\n", x);
                return;
        }

        debugger_machine = debugger_emul->machines[x];

print_current_focus_and_return:
        printf("current emul: \"%s\"\n", debugger_emul->name == NULL?
            "(no name)" : debugger_emul->name);
        printf("current machine: \"%s\"\n", debugger_machine->name == NULL?
            "(no name)" : debugger_machine->name);
}


/*  This is defined below.  */
static void debugger_cmd_help(struct machine *m, char *cmd_line);


/*
 *  debugger_cmd_itrace():
 */
static void debugger_cmd_itrace(struct machine *m, char *cmd_line)
{
        if (*cmd_line) {
                printf("syntax: itrace\n");
                return;
        }

        old_instruction_trace = 1 - old_instruction_trace;
        printf("instruction_trace = %s\n", old_instruction_trace? "ON":"OFF");
        /*  TODO: how to preserve quiet_mode?  */
        old_quiet_mode = 0;
        printf("quiet_mode = %s\n", old_quiet_mode? "ON" : "OFF");
}


/*
 *  debugger_cmd_lookup():
 */
static void debugger_cmd_lookup(struct machine *m, char *cmd_line)
{
        uint64_t addr;
        int res;
        char *symbol;
        uint64_t offset;

        if (cmd_line[0] == '\0') {
                printf("syntax: lookup name|addr\n");
                return;

        }

        /*  Addresses never need to be given in decimal form anyway,
            so assuming hex here will be ok.  */
        addr = strtoull(cmd_line, NULL, 16);

        if (addr == 0) {
                uint64_t newaddr;
                res = get_symbol_addr(&m->symbol_context,
                    cmd_line, &newaddr);
                if (!res) {
                        printf("lookup for '%s' failed\n", cmd_line);
                        return;
                }
                printf("%s = 0x%016llx\n", cmd_line, (long long)newaddr);
                return;
        }

        symbol = get_symbol_name(&m->symbol_context, addr, &offset);

        if (symbol != NULL)
                printf("0x%016llx = %s\n", (long long)addr, symbol);
        else
                printf("lookup for '%s' failed\n", cmd_line);
}


/*
 *  debugger_cmd_machine():
 *
 *  Dump info about the currently focused machine.
 */
static void debugger_cmd_machine(struct machine *m, char *cmd_line)
{
        int iadd = 4;

        if (*cmd_line) {
                printf("syntax: machine\n");
                return;
        }

        debug("machine \"%s\":\n", m->name);
        debug_indentation(iadd);
        machine_dumpinfo(m);
        debug_indentation(-iadd);
}


/*
 *  debugger_cmd_opcodestats():
 */
static void debugger_cmd_opcodestats(struct machine *m, char *cmd_line)
{
        if (*cmd_line) {
                printf("syntax: opcodestats\n");
                return;
        }

        if (!show_opcode_statistics) {
                printf("You need to start the emulator "
                    "with -s, if you want to gather statistics.\n");
        } else
                cpu_show_full_statistics(m);
}


/*
 *  debugger_cmd_pause():
 */
static void debugger_cmd_pause(struct machine *m, char *cmd_line)
{
        int cpuid = -1;

        if (cmd_line[0] != '\0')
                cpuid = atoi(cmd_line);
        else {
                printf("syntax: pause cpuid\n");
                return;
        }

        if (cpuid < 0 || cpuid >= m->ncpus) {
                printf("cpu%i doesn't exist.\n", cpuid);
                return;
        }

        m->cpus[cpuid]->running ^= 1;

        printf("cpu%i (%s) in machine \"%s\" is now %s\n", cpuid,
            m->cpus[cpuid]->name, m->name,
            m->cpus[cpuid]->running? "RUNNING" : "STOPPED");
}


/*
 *  debugger_cmd_print():
 */
static void debugger_cmd_print(struct machine *m, char *cmd_line)
{
        int res;
        uint64_t tmp;

        while (cmd_line[0] != '\0' && cmd_line[0] == ' ')
                cmd_line ++;

        if (cmd_line[0] == '\0') {
                printf("syntax: print expr\n");
                return;
        }

        res = debugger_parse_name(m, cmd_line, 0, &tmp);
        switch (res) {
        case NAME_PARSE_NOMATCH:
                printf("No match.\n");
                break;
        case NAME_PARSE_MULTIPLE:
                printf("Multiple matches. Try prefixing with %%, $, or @.\n");
                break;
        case NAME_PARSE_REGISTER:
        case NAME_PARSE_SYMBOL:
                printf("%s = 0x%016llx\n", cmd_line, (long long)tmp);
                break;
        case NAME_PARSE_NUMBER:
                printf("0x%016llx\n", (long long)tmp);
                break;
        }
}


/*
 *  debugger_cmd_put():
 */
static void debugger_cmd_put(struct machine *m, char *cmd_line)
{
        static char put_type = ' ';  /*  Remembered across multiple calls.  */
        char copy[200];
        int res, syntax_ok = 0;
        char *p, *p2, *q = NULL;
        uint64_t addr, data;
        unsigned char a_byte;

        strncpy(copy, cmd_line, sizeof(copy));
        copy[sizeof(copy)-1] = '\0';

        /*  syntax: put [b|h|w|d|q] addr, data  */

        p = strchr(copy, ',');
        if (p != NULL) {
                *p++ = '\0';
                while (*p == ' ' && *p)
                        p++;
                while (strlen(copy) >= 1 &&
                    copy[strlen(copy) - 1] == ' ')
                        copy[strlen(copy) - 1] = '\0';

                /*  printf("L = '%s', R = '%s'\n", copy, p);  */

                q = copy;
                p2 = strchr(q, ' ');

                if (p2 != NULL) {
                        *p2 = '\0';
                        if (strlen(q) != 1) {
                                printf("Invalid type '%s'\n", q);
                                return;
                        }
                        put_type = *q;
                        q = p2 + 1;
                }

                /*  printf("type '%c', L '%s', R '%s'\n", put_type, q, p);  */
                syntax_ok = 1;
        }

        if (!syntax_ok) {
                printf("syntax: put [b|h|w|d|q] addr, data\n");
                printf("   b    byte        (8 bits)\n");
                printf("   h    half-word   (16 bits)\n");
                printf("   w    word        (32 bits)\n");
                printf("   d    doubleword  (64 bits)\n");
                printf("   q    quad-word   (128 bits)\n");
                return;
        }

        if (put_type == ' ') {
                printf("No type specified.\n");
                return;
        }

        /*  here: q is the address, p is the data.  */

        res = debugger_parse_name(m, q, 0, &addr);
        switch (res) {
        case NAME_PARSE_NOMATCH:
                printf("Couldn't parse the address.\n");
                return;
        case NAME_PARSE_MULTIPLE:
                printf("Multiple matches for the address."
                    " Try prefixing with %%, $, or @.\n");
                return;
        case NAME_PARSE_REGISTER:
        case NAME_PARSE_SYMBOL:
        case NAME_PARSE_NUMBER:
                break;
        default:
                printf("INTERNAL ERROR in debugger.c.\n");
                return;
        }

        res = debugger_parse_name(m, p, 0, &data);
        switch (res) {
        case NAME_PARSE_NOMATCH:
                printf("Couldn't parse the data.\n");
                return;
        case NAME_PARSE_MULTIPLE:
                printf("Multiple matches for the data value."
                    " Try prefixing with %%, $, or @.\n");
                return;
        case NAME_PARSE_REGISTER:
        case NAME_PARSE_SYMBOL:
        case NAME_PARSE_NUMBER:
                break;
        default:
                printf("INTERNAL ERROR in debugger.c.\n");
                return;
        }

        /*  TODO: haha, maybe this should be refactored  */

        switch (put_type) {
        case 'b':
                a_byte = data;
                printf("0x%016llx: %02x", (long long)addr, a_byte);
                if (data > 255)
                        printf(" (NOTE: truncating %0llx)", (long long)data);
                res = m->cpus[0]->memory_rw(m->cpus[0], m->cpus[0]->mem, addr,
                    &a_byte, 1, MEM_WRITE, CACHE_NONE | NO_EXCEPTIONS);
                if (!res)
                        printf("  FAILED!\n");
                printf("\n");
                return;
        case 'h':
                if ((data & 1) != 0)
                        printf("WARNING: address isn't aligned\n");
                printf("0x%016llx: %04x", (long long)addr, (int)data);
                if (data > 0xffff)
                        printf(" (NOTE: truncating %0llx)", (long long)data);
                res = store_16bit_word(m->cpus[0], addr, data);
                if (!res)
                        printf("  FAILED!\n");
                printf("\n");
                return;
        case 'w':
                if ((data & 3) != 0)
                        printf("WARNING: address isn't aligned\n");
                printf("0x%016llx: %08x", (long long)addr, (int)data);
                if (data > 0xffffffff && (data >> 32) != 0
                    && (data >> 32) != 0xffffffff)
                        printf(" (NOTE: truncating %0llx)", (long long)data);
                res = store_32bit_word(m->cpus[0], addr, data);
                if (!res)
                        printf("  FAILED!\n");
                printf("\n");
                return;
        case 'd':
                if ((data & 7) != 0)
                        printf("WARNING: address isn't aligned\n");
                printf("0x%016llx: %016llx", (long long)addr, (long long)data);
                res = store_64bit_word(m->cpus[0], addr, data);
                if (!res)
                        printf("  FAILED!\n");
                printf("\n");
                return;
        case 'q':
                printf("quad-words: TODO\n");
                /*  TODO  */
                return;
        default:
                printf("Unimplemented type '%c'\n", put_type);
                return;
        }
}


/*
 *  debugger_cmd_quiet():
 */
static void debugger_cmd_quiet(struct machine *m, char *cmd_line)
{
        int toggle = 1;
        int previous_mode = old_quiet_mode;

        if (cmd_line[0] != '\0') {
                while (cmd_line[0] != '\0' && cmd_line[0] == ' ')
                        cmd_line ++;
                switch (cmd_line[0]) {
                case '0':
                        toggle = 0;
                        old_quiet_mode = 0;
                        break;
                case '1':
                        toggle = 0;
                        old_quiet_mode = 1;
                        break;
                case 'o':
                case 'O':
                        toggle = 0;
                        switch (cmd_line[1]) {
                        case 'n':
                        case 'N':
                                old_quiet_mode = 1;
                                break;
                        default:
                                old_quiet_mode = 0;
                        }
                        break;
                default:
                        printf("syntax: quiet [on|off]\n");
                        return;
                }
        }

        if (toggle)
                old_quiet_mode = 1 - old_quiet_mode;

        printf("quiet_mode = %s", old_quiet_mode? "ON" : "OFF");
        if (old_quiet_mode != previous_mode)
                printf("  (was: %s)", previous_mode? "ON" : "OFF");
        printf("\n");
}


/*
 *  debugger_cmd_quit():
 */
static void debugger_cmd_quit(struct machine *m, char *cmd_line)
{
        int i, j, k;
        struct emul *e;

        if (*cmd_line) {
                printf("syntax: quit\n");
                return;
        }

        for (i=0; i<debugger_n_emuls; i++) {
                single_step = 0;

                e = debugger_emuls[i];
                force_debugger_at_exit = 0;

                for (j=0; j<e->n_machines; j++) {
                        struct machine *m = e->machines[j];

                        for (k=0; k<m->ncpus; k++)
                                m->cpus[k]->running = 0;

                        m->exit_without_entering_debugger = 1;
                }
        }

        exit_debugger = 1;
}


/*
 *  debugger_cmd_reg():
 */
static void debugger_cmd_reg(struct machine *m, char *cmd_line)
{
        int i, cpuid = -1, coprocnr = -1;
        int gprs, coprocs;
        char *p;

        /*  [cpuid][,c]  */
        if (cmd_line[0] != '\0') {
                if (cmd_line[0] != ',') {
                        cpuid = strtoull(cmd_line, NULL, 0);
                        if (cpuid < 0 || cpuid >= m->ncpus) {
                                printf("cpu%i doesn't exist.\n", cpuid);
                                return;
                        }
                }
                p = strchr(cmd_line, ',');
                if (p != NULL) {
                        coprocnr = atoi(p + 1);
                        if (coprocnr < 0 || coprocnr >= 4) {
                                printf("Invalid coprocessor number.\n");
                                return;
                        }
                }
        }

        gprs = (coprocnr == -1)? 1 : 0;
        coprocs = (coprocnr == -1)? 0x0 : (1 << coprocnr);

        for (i=0; i<m->ncpus; i++)
                if (cpuid == -1 || i == cpuid)
                        cpu_register_dump(m, m->cpus[i], gprs, coprocs);
}


/*
 *  debugger_cmd_step():
 */
static void debugger_cmd_step(struct machine *m, char *cmd_line)
{
        int n = 1;

        if (cmd_line[0] != '\0') {
                n = strtoull(cmd_line, NULL, 0);
                if (n < 1) {
                        printf("invalid nr of steps\n");
                        return;
                }
        }

        n_steps_left_before_interaction = n - 1;

        /*  Special hack, see debugger() for more info.  */
        exit_debugger = -1;

        strcpy(repeat_cmd, "step");
}


/*
 *  debugger_cmd_tlbdump():
 *
 *  Dump each CPU's TLB contents.
 */
static void debugger_cmd_tlbdump(struct machine *m, char *cmd_line)
{
        int x = -1;
        int rawflag = 0;

        if (cmd_line[0] != '\0') {
                char *p;
                if (cmd_line[0] != ',') {
                        x = strtoull(cmd_line, NULL, 0);
                        if (x < 0 || x >= m->ncpus) {
                                printf("cpu%i doesn't exist.\n", x);
                                return;
                        }
                }
                p = strchr(cmd_line, ',');
                if (p != NULL) {
                        switch (p[1]) {
                        case 'r':
                        case 'R':
                                rawflag = 1;
                                break;
                        default:
                                printf("Unknown tlbdump flag.\n");
                                printf("syntax: tlbdump [cpuid][,r]\n");
                                return;
                        }
                }
        }

        cpu_tlbdump(m, x, rawflag);
}


/*
 *  debugger_cmd_trace():
 */
static void debugger_cmd_trace(struct machine *m, char *cmd_line)
{
        if (*cmd_line) {
                printf("syntax: trace\n");
                return;
        }

        old_show_trace_tree = 1 - old_show_trace_tree;
        printf("show_trace_tree = %s\n", old_show_trace_tree? "ON" : "OFF");

        if (m->bintrans_enable && old_show_trace_tree)
                printf("NOTE: the trace tree functionality doesn't "
                    "work very well with bintrans!\n");

        /*  TODO: how to preserve quiet_mode?  */
        old_quiet_mode = 0;
        printf("quiet_mode = %s\n", old_quiet_mode? "ON" : "OFF");
}


/*
 *  debugger_cmd_unassemble():
 *
 *  Dump emulated memory as instructions.
 *
 *  syntax: unassemble [addr [endaddr]]
 */
static void debugger_cmd_unassemble(struct machine *m, char *cmd_line)
{
        uint64_t addr, addr_start, addr_end;
        struct cpu *c;
        struct memory *mem;
        char *p = NULL;
        int r, lines_left = -1;

        if (cmd_line[0] != '\0') {
                uint64_t tmp;
                char *tmps = strdup(cmd_line);

                /*  addr:  */
                p = strchr(tmps, ' ');
                if (p != NULL)
                        *p = '\0';
                r = debugger_parse_name(m, tmps, 0, &tmp);
                free(tmps);

                if (r == NAME_PARSE_NOMATCH || r == NAME_PARSE_MULTIPLE) {
                        printf("Unparsable address: %s\n", cmd_line);
                        return;
                } else {
                        last_unasm_addr = tmp;
                }

                p = strchr(cmd_line, ' ');
        }

        addr_start = last_unasm_addr;

        if (addr_start == MAGIC_UNTOUCHED) {
                uint64_t tmp;
                int match_register = 0;
                cpu_register_match(m, "pc", 0, &tmp, &match_register);
                if (match_register) {
                        addr_start = tmp;
                } else {
                        printf("No starting address.\n");
                        return;
                }
        }

        addr_end = addr_start + 1000;

        /*  endaddr:  */
        if (p != NULL) {
                while (*p == ' ' && *p)
                        p++;
                r = debugger_parse_name(m, p, 0, &addr_end);
                if (r == NAME_PARSE_NOMATCH || r == NAME_PARSE_MULTIPLE) {
                        printf("Unparsable address: %s\n", cmd_line);
                        return;
                }
        } else
                lines_left = 20;

        if (m->cpus == NULL) {
                printf("No cpus (?)\n");
                return;
        }
        c = m->cpus[m->bootstrap_cpu];
        if (c == NULL) {
                printf("m->cpus[m->bootstrap_cpu] = NULL\n");
                return;
        }
        mem = m->cpus[m->bootstrap_cpu]->mem;

        addr = addr_start;

        ctrl_c = 0;

        while (addr < addr_end) {
                int i, len;
                unsigned char buf[32];  /*  TODO: How long can an
                                            instruction be, on weird archs?  */
                memset(buf, 0, sizeof(buf));

                for (i=0; i<sizeof(buf); i++)
                        c->memory_rw(c, mem, addr+i, buf+i, 1, MEM_READ,
                            CACHE_NONE | NO_EXCEPTIONS);

                len = cpu_disassemble_instr(m, c, buf, 0, addr, 0);

                if (ctrl_c)
                        return;
                if (len == 0)
                        break;

                addr += len;

                if (lines_left != -1) {
                        lines_left --;
                        if (lines_left == 0)
                                break;
                }
        }

        last_unasm_addr = addr;

        strcpy(repeat_cmd, "unassemble");
}


/*
 *  debugger_cmd_version():
 */
static void debugger_cmd_version(struct machine *m, char *cmd_line)
{
        if (*cmd_line) {
                printf("syntax: version\n");
                return;
        }

#ifdef VERSION
        printf("%s, %s\n", VERSION, COMPILE_DATE);
#else
        printf("(no version), %s\n", COMPILE_DATE);
#endif
}


struct cmd {
        char    *name;
        char    *args;
        int     tmp_flag;
        void    (*f)(struct machine *, char *cmd_line);
        char    *description;
};

static struct cmd cmds[] = {
        { "breakpoint", "...", 0, debugger_cmd_breakpoint,
                "manipulate breakpoints" },

        { "bintrans", "[on|off]", 0, debugger_cmd_bintrans,
                "toggle bintrans on or off" },

        /*  NOTE: Try to keep 'c' down to only one command. Having 'continue'
            available as a one-letter command is very convenient.  */

        { "continue", "", 0, debugger_cmd_continue,
                "continue execution" },

        { "device", "...", 0, debugger_cmd_device,
                "show info about (or manipulate) devices" },

        { "dump", "[addr [endaddr]]", 0, debugger_cmd_dump,
                "dump memory contents in hex and ASCII" },

        { "emuls", "", 0, debugger_cmd_emuls,
                "print a summary of all current emuls" },

        { "focus", "x[,y]", 0, debugger_cmd_focus,
                "changes focus to machine x (in emul y)" },

        { "help", "", 0, debugger_cmd_help,
                "print this help message" },

        { "itrace", "", 0, debugger_cmd_itrace,
                "toggle instruction_trace on or off" },

        { "lookup", "name|addr", 0, debugger_cmd_lookup,
                "lookup a symbol by name or address" },

        { "machine", "", 0, debugger_cmd_machine,
                "print a summary of the current machine" },

        { "opcodestats", "", 0, debugger_cmd_opcodestats,
                "show opcode statistics" },

        { "pause", "cpuid", 0, debugger_cmd_pause,
                "pause (or unpause) a CPU" },

        { "print", "expr", 0, debugger_cmd_print,
                "evaluate an expression without side-effects" },

        { "put", "[b|h|w|d|q] addr, data", 0, debugger_cmd_put,
                "modify emulated memory contents" },

        { "quiet", "[on|off]", 0, debugger_cmd_quiet,
                "toggle quiet_mode on or off" },

        { "quit", "", 0, debugger_cmd_quit,
                "quit the emulator" },

        { "reg", "[cpuid][,c]", 0, debugger_cmd_reg,
                "show GPRs (or coprocessor c's registers)" },

        /*  NOTE: Try to keep 's' down to only one command. Having 'step'
            available as a one-letter command is very convenient.  */

        { "step", "[n]", 0, debugger_cmd_step,
                "single-step one (or n) instruction(s)" },

        { "tlbdump", "[cpuid][,r]", 0, debugger_cmd_tlbdump,
                "dump TLB contents (add ',r' for raw data)" },

        { "trace", "", 0, debugger_cmd_trace,
                "toggle show_trace_tree on or off" },

        { "unassemble", "[addr [endaddr]]", 0, debugger_cmd_unassemble,
                "dump memory contents as instructions" },

        { "version", "", 0, debugger_cmd_version,
                "print version information" },

        { NULL, NULL, 0, NULL, NULL }
};


/*
 *  debugger_cmd_help():
 *
 *  Print a list of available commands.
 *
 *  NOTE: This is placed after the cmds[] array, because it needs to
 *  access it.
 */
static void debugger_cmd_help(struct machine *m, char *cmd_line)
{
        int i, j, max_name_len = 0;

        i = 0;
        while (cmds[i].name != NULL) {
                int a = strlen(cmds[i].name);
                if (cmds[i].args != NULL)
                        a += 1 + strlen(cmds[i].args);
                if (a > max_name_len)
                        max_name_len = a;
                i++;
        }

        printf("Available commands:\n");

        i = 0;
        while (cmds[i].name != NULL) {
                char buf[100];
                snprintf(buf, sizeof(buf), "%s", cmds[i].name);
                if (cmds[i].args != NULL)
                        snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
                            " %s", cmds[i].args);

                printf("  ");
                for (j=0; j<max_name_len; j++)
                        if (j < strlen(buf))
                                printf("%c", buf[j]);
                        else
                                printf(" ");

                printf("   %s\n", cmds[i].description);
                i++;
        }

        printf("Generic assignments:   x = expr\n");
        printf("where x must be a register, and expr can be a register, a "
            "numeric value, or\na symbol name (+ an optional numeric offset)."
            " In case there are multiple\nmatches (ie a symbol that has the "
            "same name as a register), you may add a\nprefix character as a "
            "hint: '%%' for registers, '@' for symbols, and\n'$' for numeric"
            " values. Use 0x for hexadecimal values.\n");
}


/****************************************************************************/


/*
 *  debugger_assignment():
 *
 *  cmd contains something like "pc=0x80001000", or "r31=memcpy+0x40".
 */
void debugger_assignment(struct machine *m, char *cmd)
{
        char *left, *right;
        int res_left, res_right;
        uint64_t tmp;

        left  = malloc(strlen(cmd) + 1);
        if (left == NULL) {
                fprintf(stderr, "out of memory in debugger_assignment()\n");
                exit(1);
        }
        strcpy(left, cmd);
        right = strchr(left, '=');
        if (right == NULL) {
                fprintf(stderr, "internal error in the debugger\n");
                exit(1);
        }
        *right = '\0';

        /*  Remove trailing spaces in left:  */
        while (strlen(left) >= 1 && left[strlen(left)-1] == ' ')
                left[strlen(left)-1] = '\0';

        /*  Remove leading spaces in right:  */
        right++;
        while (*right == ' ' && *right != '\0')
                right++;

        /*  printf("left  = '%s'\nright = '%s'\n", left, right);  */

        res_right = debugger_parse_name(m, right, 0, &tmp);
        switch (res_right) {
        case NAME_PARSE_NOMATCH:
                printf("No match for the right-hand side of the assignment.\n");
                break;
        case NAME_PARSE_MULTIPLE:
                printf("Multiple matches for the right-hand side of the "
                    "assignment.\n");
                break;
        default:
                res_left = debugger_parse_name(m, left, 1, &tmp);
                switch (res_left) {
                case NAME_PARSE_NOMATCH:
                        printf("No match for the left-hand side of the "
                            "assignment.\n");
                        break;
                case NAME_PARSE_MULTIPLE:
                        printf("Multiple matches for the left-hand side "
                            "of the assignment.\n");
                        break;
                default:
                        debugger_cmd_print(m, left);
                }
        }

        free(left);
}


/*
 *  debugger_readline():
 *
 *  Read a line from the terminal.
 */
static char *debugger_readline(void)
{
        int ch, i, j, n, i_match, reallen, cmd_len, cursor_pos;
        int read_from_index = last_cmd_index;
        char *cmd = last_cmd[last_cmd_index];

        cmd_len = 0; cmd[0] = '\0';
        printf("GXemul> ");
        fflush(stdout);

        ch = '\0';
        cmd_len = 0;
        cursor_pos = 0;

        while (ch != '\n') {
                /*
                 *  TODO: This uses up 100% CPU, maybe that isn't too good.
                 *  The usleep() call might make it a tiny bit nicer on other
                 *  running processes, but it is still very ugly.
                 */
                while ((ch = console_readchar(MAIN_CONSOLE)) < 0) {
                        x11_check_event(debugger_emuls, debugger_n_emuls);
                        usleep(2);
                }

                if ((ch == '\b' || ch == 127) && cursor_pos > 0) {
                        /*  Backspace.  */
                        cursor_pos --;
                        cmd_len --;
                        memmove(cmd + cursor_pos, cmd + cursor_pos + 1,
                            cmd_len);
                        cmd[cmd_len] = '\0';
                        printf("\b");
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("%c", cmd[i]);
                        printf(" \b");
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("\b");
                } else if (ch == 4 && cmd_len > 0 && cursor_pos < cmd_len) {
                        /*  CTRL-D: Delete.  */
                        cmd_len --;
                        memmove(cmd + cursor_pos, cmd + cursor_pos + 1,
                            cmd_len);
                        cmd[cmd_len] = '\0';
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("%c", cmd[i]);
                        printf(" \b");
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("\b");
                } else if (ch == 1) {
                        /*  CTRL-A: Start of line.  */
                        while (cursor_pos > 0) {
                                cursor_pos --;
                                printf("\b");
                        }
                } else if (ch == 2) {
                        /*  CTRL-B: Backwards one character.  */
                        if (cursor_pos > 0) {
                                printf("\b");
                                cursor_pos --;
                        }
                } else if (ch == 5) {
                        /*  CTRL-E: End of line.  */
                        while (cursor_pos < cmd_len) {
                                printf("%c", cmd[cursor_pos]);
                                cursor_pos ++;
                        }
                } else if (ch == 6) {
                        /*  CTRL-F: Forward one character.  */
                        if (cursor_pos < cmd_len) {
                                printf("%c",
                                    cmd[cursor_pos]);
                                cursor_pos ++;
                        }
                } else if (ch == 11) {
                        /*  CTRL-K: Kill to end of line.  */
                        for (i=0; i<MAX_CMD_LEN; i++)
                                console_makeavail(MAIN_CONSOLE, 4); /*  :-)  */
                } else if (ch == 14 || ch == 16) {
                        /*  CTRL-P: Previous line in the command history,
                            CTRL-N: next line  */
                        do {
                                if (ch == 14 &&
                                    read_from_index == last_cmd_index)
                                        break;
                                if (ch == 16)
                                        i = read_from_index - 1;
                                else
                                        i = read_from_index + 1;

                                if (i < 0)
                                        i = N_PREVIOUS_CMDS - 1;
                                if (i >= N_PREVIOUS_CMDS)
                                        i = 0;

                                /*  Special case: pressing 'down'
                                    to reach last_cmd_index:  */
                                if (i == last_cmd_index) {
                                        read_from_index = i;
                                        for (i=cursor_pos; i<cmd_len;
                                            i++)
                                                printf(" ");
                                        for (i=cmd_len-1; i>=0; i--)
                                                printf("\b \b");
                                        cmd[0] = '\0';
                                        cmd_len = cursor_pos = 0;
                                } else if (last_cmd[i][0] != '\0') {
                                        /*  Copy from old line:  */
                                        read_from_index = i;
                                        for (i=cursor_pos; i<cmd_len;
                                            i++)
                                                printf(" ");
                                        for (i=cmd_len-1; i>=0; i--)
                                                printf("\b \b");
                                        strcpy(cmd,
                                            last_cmd[read_from_index]);
                                        cmd_len = strlen(cmd);
                                        printf("%s", cmd);
                                        cursor_pos = cmd_len;
                                }
                        } while (0);
                } else if (ch >= ' ' && cmd_len < MAX_CMD_LEN) {
                        /*  Visible character:  */
                        memmove(cmd + cursor_pos + 1, cmd + cursor_pos,
                            cmd_len - cursor_pos);
                        cmd[cursor_pos] = ch;
                        cmd_len ++;
                        cursor_pos ++;
                        cmd[cmd_len] = '\0';
                        printf("%c", ch);
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("%c", cmd[i]);
                        for (i=cursor_pos; i<cmd_len; i++)
                                printf("\b");
                } else if (ch == '\r' || ch == '\n') {
                        ch = '\n';
                        printf("\n");
                } else if (ch == '\t') {
                        /*  Super-simple tab-completion:  */
                        i = 0;
                        while (cmds[i].name != NULL)
                                cmds[i++].tmp_flag = 0;

                        /*  Check for a (partial) command match:  */
                        n = i = i_match = 0;
                        while (cmds[i].name != NULL) {
                                if (strncasecmp(cmds[i].name, cmd,
                                    cmd_len) == 0) {
                                        cmds[i].tmp_flag = 1;
                                        i_match = i;
                                        n++;
                                }
                                i++;
                        }

                        switch (n) {
                        case 0: /*  Beep.  */
                                printf("\a");
                                break;
                        case 1: /*  Add the rest of the command:  */
                                reallen = strlen(cmds[i_match].name);
                                for (i=cmd_len; i<reallen; i++)
                                        console_makeavail(MAIN_CONSOLE,
                                            cmds[i_match].name[i]);
                                /*  ... and a space, if the command takes
                                    any arguments:  */
                                if (cmds[i_match].args != NULL &&
                                    cmds[i_match].args[0] != '\0')
                                        console_makeavail(MAIN_CONSOLE, ' ');
                                break;
                        default:
                                /*  Show all possible commands:  */
                                printf("\a\n"); /*  Beep. :-)  */
                                i = 0;          /*  i = cmds index  */
                                j = 0;          /*  j = # of cmds printed  */
                                while (cmds[i].name != NULL) {
                                        if (cmds[i].tmp_flag) {
                                                int q;
                                                if (j == 0)
                                                        printf("  ");
                                                printf("%s",
                                                    cmds[i].name);
                                                j++;
                                                if (j != 6)
                                                        for (q=0; q<13-strlen(
                                                            cmds[i].name); q++)
                                                                printf(" ");
                                                if (j == 6) {
                                                        printf("\n");
                                                        j = 0;
                                                }
                                        }
                                        i++;
                                }
                                if (j != 0)
                                        printf("\n");
                                printf("GXemul> ");
                                for (i=0; i<cmd_len; i++)
                                        printf("%c", cmd[i]);
                        }
                } else if (ch == 27) {
                        /*  Escape codes: (cursor keys etc)  */
                        while ((ch = console_readchar(MAIN_CONSOLE)) < 0)
                                usleep(1);
                        if (ch == '[' || ch == 'O') {
                                while ((ch = console_readchar(MAIN_CONSOLE))
                                    < 0)
                                        usleep(1);
                                switch (ch) {
                                case '2':       /*  2~ = ins  */
                                case '5':       /*  5~ = pgup  */
                                case '6':       /*  6~ = pgdn  */
                                        /*  TODO: Ugly hack, but might work.  */
                                        while ((ch = console_readchar(
                                            MAIN_CONSOLE)) < 0)
                                                usleep(1);
                                        /*  Do nothing for these keys.  */
                                        break;
                                case '3':       /*  3~ = delete  */
                                        /*  TODO: Ugly hack, but might work.  */
                                        while ((ch = console_readchar(
                                            MAIN_CONSOLE)) < 0)
                                                usleep(1);
                                        console_makeavail(MAIN_CONSOLE, '\b');
                                        break;
                                case 'A':       /*  Up.  */
                                        /*  Up cursor ==> CTRL-P  */
                                        console_makeavail(MAIN_CONSOLE, 16);
                                        break;
                                case 'B':       /*  Down.  */
                                        /*  Down cursor ==> CTRL-N  */
                                        console_makeavail(MAIN_CONSOLE, 14);
                                        break;
                                case 'C':
                                        /*  Right cursor ==> CTRL-F  */
                                        console_makeavail(MAIN_CONSOLE, 6);
                                        break;
                                case 'D':       /*  Left  */
                                        /*  Left cursor ==> CTRL-B  */
                                        console_makeavail(MAIN_CONSOLE, 2);
                                        break;
                                case 'F':
                                        /*  End ==> CTRL-E  */
                                        console_makeavail(MAIN_CONSOLE, 5);
                                        break;
                                case 'H':
                                        /*  Home ==> CTRL-A  */
                                        console_makeavail(MAIN_CONSOLE, 1);
                                        break;
                                }
                        }
                }

                fflush(stdout);
        }

        return cmd;
}


/*
 *  debugger():
 *
 *  This is a loop, which reads a command from the terminal, and executes it.
 */
void debugger(void)
{
        int i, n, i_match, matchlen, cmd_len;
        char *cmd;

        if (n_steps_left_before_interaction > 0) {
                n_steps_left_before_interaction --;
                return;
        }

        exit_debugger = 0;

        while (!exit_debugger) {
                /*  Read a line from the terminal:  */
                cmd = debugger_readline();
                cmd_len = strlen(cmd);

                /*  Remove spaces:  */
                while (cmd_len > 0 && cmd[0]==' ')
                        memmove(cmd, cmd+1, cmd_len --);
                while (cmd_len > 0 && cmd[cmd_len-1] == ' ')
                        cmd[(cmd_len--)-1] = '\0';

                /*  No command? Then try reading another line.  */
                if (cmd_len == 0) {
                        /*  Special case for repeated commands:  */
                        if (repeat_cmd[0] != '\0')
                                strcpy(cmd, repeat_cmd);
                        else
                                continue;
                } else {
                        last_cmd_index ++;
                        if (last_cmd_index >= N_PREVIOUS_CMDS)
                                last_cmd_index = 0;

                        repeat_cmd[0] = '\0';
                }

                /*
                 *  Is there a '=' on the command line? Then try to do an
                 *  assignment.  (Only if there is just one word, followed
                 *  by the '=' sign. This makes it possible to use commands
                 *  such as "device add name addr=xyz".)
                 */
                if (strchr(cmd, '=') != NULL) {
                        /*  Count the nr of words:  */
                        int nw = 0, inword = 0;
                        char *p = cmd;
                        while (*p) {
                                if (*p == '=')
                                        break;
                                if (*p != ' ') {
                                        if (!inword)
                                                nw ++;
                                        inword = 1;
                                } else
                                        inword = 0;
                                p++;
                        }

                        if (nw == 1) {
                                debugger_assignment(debugger_machine, cmd);
                                continue;
                        }
                }

                i = 0;
                while (cmds[i].name != NULL)
                        cmds[i++].tmp_flag = 0;

                /*  How many chars in cmd to match against:  */
                matchlen = 0;
                while (isalpha((int)cmd[matchlen]))
                        matchlen ++;

                /*  Check for a command name match:  */
                n = i = i_match = 0;
                while (cmds[i].name != NULL) {
                        if (strncasecmp(cmds[i].name, cmd, matchlen) == 0) {
                                cmds[i].tmp_flag = 1;
                                i_match = i;
                                n++;
                        }
                        i++;
                }

                /*  No match?  */
                if (n == 0) {
                        printf("Unknown command '%s'. "
                            "Type 'help' for help.\n", cmd);
                        continue;
                }

                /*  More than one match?  */
                if (n > 1) {
                        printf("Ambiguous command '%s':  ", cmd);
                        i = 0;
                        while (cmds[i].name != NULL) {
                                if (cmds[i].tmp_flag)
                                        printf("  %s", cmds[i].name);
                                i++;
                        }
                        printf("\n");
                        continue;
                }

                /*  Exactly one match:  */
                if (cmds[i_match].f != NULL) {
                        char *p = cmd + matchlen;
                        /*  Remove leading whitespace from the args...  */
                        while (*p != '\0' && *p == ' ')
                                p++;

                        /*  ... and run the command:  */
                        cmds[i_match].f(debugger_machine, p);
                } else
                        printf("FATAL ERROR: internal error in debugger.c:"
                            " no handler for this command?\n");

                /*  Special hack for the "step" command:  */
                if (exit_debugger == -1)
                        return;
        }

        single_step = 0;
        debugger_machine->instruction_trace = old_instruction_trace;
        debugger_machine->show_trace_tree = old_show_trace_tree;
        quiet_mode = old_quiet_mode;
}


/*
 *  debugger_reset():
 *
 *  This function should be called before calling debugger(), when it is
 *  absolutely necessary that debugger() is interactive. Otherwise, it might
 *  return without doing anything, such as when single-stepping multiple
 *  instructions at a time.
 */
void debugger_reset(void)
{
        n_steps_left_before_interaction = 0;
}


/*
 *  debugger_init():
 *
 *  Must be called before any other debugger function is used.
 */
void debugger_init(struct emul **emuls, int n_emuls)
{
        int i;

        debugger_n_emuls = n_emuls;
        debugger_emuls = emuls;

        if (n_emuls < 1) {
                fprintf(stderr, "\nERROR: No emuls (?)\n");
                exit(1);
        }

        debugger_emul = emuls[0];
        if (emuls[0]->n_machines < 1) {
                fprintf(stderr, "\nERROR: No machines in emuls[0], "
                    "cannot handle this situation yet.\n\n");
                exit(1);
        }

        debugger_machine = emuls[0]->machines[0];

        for (i=0; i<N_PREVIOUS_CMDS; i++) {
                last_cmd[i] = malloc(MAX_CMD_LEN + 1);
                if (last_cmd[i] == NULL) {
                        fprintf(stderr, "debugger_init(): out of memory\n");
                        exit(1);
                }
                last_cmd[i][0] = '\0';
        }

        last_cmd_index = 0;
        repeat_cmd[0] = '\0';
}
