trunk/src/machine.c

/*
 *  Copyright (C) 2003-2007  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: machine.c,v 1.693 2007/01/28 14:15:29 debug Exp $
 */

#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "arcbios.h"
#include "bus_isa.h"
#include "bus_pci.h"
#include "cpu.h"
#include "debugger.h"
#include "device.h"
#include "devices.h"
#include "diskimage.h"
#include "emul.h"
#include "machine.h"
#include "memory.h"
#include "misc.h"
#include "net.h"
#include "settings.h"
#include "symbol.h"


/*  See main.c:  */
extern int quiet_mode;
extern int verbose;


/*  This is initialized by machine_init():  */
struct machine_entry *first_machine_entry = NULL;


/*
 *  machine_new():
 *
 *  Returns a reasonably initialized struct machine.
 */
struct machine *machine_new(char *name, struct emul *emul, int id)
{
        struct machine *m;
        m = malloc(sizeof(struct machine));
        if (m == NULL) {
                fprintf(stderr, "machine_new(): out of memory\n");
                exit(1);
        }

        memset(m, 0, sizeof(struct machine));

        /*  Pointer back to the emul object that this machine belongs to:  */
        m->emul = emul;

        m->name = strdup(name);

        /*  Full path, e.g. "emul[0].machine[0]":  */
        m->path = malloc(strlen(emul->path) + 20);
        if (m->path == NULL) {
                fprintf(stderr, "out of memory\n");
                exit(1);
        }
        snprintf(m->path, strlen(emul->path) + 20, "%s.machine[%i]",
            emul->path, id);

        /*  Sane default values:  */
        m->serial_nr = 1;
        m->machine_type = MACHINE_NONE;
        m->machine_subtype = MACHINE_NONE;
        m->arch_pagesize = 4096;        /*  Should be overriden in
                                            emul.c for other pagesizes.  */
        m->prom_emulation = 1;
        m->allow_instruction_combinations = 1;
        m->byte_order_override = NO_BYTE_ORDER_OVERRIDE;
        m->boot_kernel_filename = "";
        m->boot_string_argument = NULL;
        m->x11_scaledown = 1;
        m->x11_scaleup = 1;
        m->n_gfx_cards = 1;
        m->dbe_on_nonexistant_memaccess = 1;
        m->show_symbolic_register_names = 1;
        symbol_init(&m->symbol_context);

        /*  Settings:  */
        m->settings = settings_new();
        settings_add(m->settings, "name", 0,
            SETTINGS_TYPE_STRING, SETTINGS_FORMAT_STRING,
            (void *) &m->name);
        settings_add(m->settings, "serial_nr", 0,
            SETTINGS_TYPE_INT, SETTINGS_FORMAT_DECIMAL,
            (void *) &m->serial_nr);
        settings_add(m->settings, "arch_pagesize", 0,
            SETTINGS_TYPE_INT, SETTINGS_FORMAT_DECIMAL,
            (void *) &m->arch_pagesize);
        settings_add(m->settings, "prom_emulation", 0,
            SETTINGS_TYPE_INT, SETTINGS_FORMAT_YESNO,
            (void *) &m->prom_emulation);
        settings_add(m->settings, "allow_instruction_combinations", 0,
            SETTINGS_TYPE_INT, SETTINGS_FORMAT_YESNO,
            (void *) &m->allow_instruction_combinations);
        settings_add(m->settings, "n_gfx_cards", 0,
            SETTINGS_TYPE_INT, SETTINGS_FORMAT_DECIMAL,
            (void *) &m->n_gfx_cards);
        settings_add(m->settings, "show_symbolic_register_names", 1,
            SETTINGS_TYPE_INT, SETTINGS_FORMAT_YESNO,
            (void *) &m->show_symbolic_register_names);
        settings_add(m->settings, "statistics_enabled", 1,
            SETTINGS_TYPE_INT, SETTINGS_FORMAT_YESNO,
            (void *) &m->statistics_enabled);

        return m;
}


/*
 *  machine_destroy():
 *
 *  Destroys a machine object.
 */
void machine_destroy(struct machine *machine)
{
        int i;

        for (i=0; i<machine->ncpus; i++)
                cpu_destroy(machine->cpus[i]);

        if (machine->name != NULL)
                free(machine->name);

        if (machine->path != NULL)
                free(machine->path);

        /*  Remove any remaining level-1 settings:  */
        settings_remove_all(machine->settings);
        settings_destroy(machine->settings);

        free(machine);
}


/*
 *  machine_name_to_type():
 *
 *  Take a type and a subtype as strings, and convert them into numeric
 *  values used internally throughout the code.
 *
 *  Return value is 1 on success, 0 if there was no match.
 *  Also, any errors/warnings are printed using fatal()/debug().
 */
int machine_name_to_type(char *stype, char *ssubtype,
        int *type, int *subtype, int *arch)
{
        struct machine_entry *me;
        int i, j, k, nmatches = 0;

        *type = MACHINE_NONE;
        *subtype = 0;

        /*  Check stype, and optionally ssubtype:  */
        me = first_machine_entry;
        while (me != NULL) {
                for (i=0; i<me->n_aliases; i++)
                        if (strcasecmp(me->aliases[i], stype) == 0) {
                                /*  Found a type:  */
                                *type = me->machine_type;
                                *arch = me->arch;

                                if (me->n_subtypes == 0)
                                        return 1;

                                /*  Check for subtype:  */
                                for (j=0; j<me->n_subtypes; j++)
                                        for (k=0; k<me->subtype[j]->n_aliases;
                                            k++)
                                                if (strcasecmp(ssubtype,
                                                    me->subtype[j]->aliases[k]
                                                    ) == 0) {
                                                        *subtype = me->subtype[
                                                            j]->machine_subtype;
                                                        return 1;
                                                }

                                fatal("Unknown subtype '%s' for emulation"
                                    " '%s'\n", ssubtype, stype);
                                if (!ssubtype[0])
                                        fatal("(Maybe you forgot the -e"
                                            " command line option?)\n");
                                exit(1);
                        }

                me = me->next;
        }

        /*  Not found? Then just check ssubtype:  */
        me = first_machine_entry;
        while (me != NULL) {
                if (me->n_subtypes == 0) {
                        me = me->next;
                        continue;
                }

                /*  Check for subtype:  */
                for (j=0; j<me->n_subtypes; j++)
                        for (k=0; k<me->subtype[j]->n_aliases; k++)
                                if (strcasecmp(ssubtype, me->subtype[j]->
                                    aliases[k]) == 0) {
                                        *type = me->machine_type;
                                        *arch = me->arch;
                                        *subtype = me->subtype[j]->
                                            machine_subtype;
                                        nmatches ++;
                                }

                me = me->next;
        }

        switch (nmatches) {
        case 0: fatal("\nSorry, emulation \"%s\"", stype);
                if (ssubtype != NULL && ssubtype[0] != '\0')
                        fatal(" (subtype \"%s\")", ssubtype);
                fatal(" is unknown.\n");
                break;
        case 1: return 1;
        default:fatal("\nSorry, multiple matches for \"%s\"", stype);
                if (ssubtype != NULL && ssubtype[0] != '\0')
                        fatal(" (subtype \"%s\")", ssubtype);
                fatal(".\n");
        }

        *type = MACHINE_NONE;
        *subtype = 0;

        fatal("Use the -H command line option to get a list of "
            "available types and subtypes.\n\n");

        return 0;
}


/*
 *  machine_add_tickfunction():
 *
 *  Adds a tick function (a function called every now and then, depending on
 *  clock cycle count) to a machine.
 *
 *  If tickshift is non-zero, a tick will occur every (1 << tickshift) cycles.
 *  This is used for the normal (fast dyntrans) emulation modes.
 *
 *  If tickshift is zero, then this is a cycle-accurate tick function.
 *  The hz value is used in this case.
 */
void machine_add_tickfunction(struct machine *machine, void (*func)
        (struct cpu *, void *), void *extra, int tickshift, double hz)
{
        int n = machine->n_tick_entries;

        if (n >= MAX_TICK_FUNCTIONS) {
                fprintf(stderr, "machine_add_tickfunction(): too "
                    "many tick functions\n");
                exit(1);
        }

        if (!machine->cycle_accurate) {
                /*
                 *  The dyntrans subsystem wants to run code in relatively
                 *  large chunks without checking for external interrupts;
                 *  too low tickshifts are not allowed.
                 */
                if (tickshift < N_SAFE_DYNTRANS_LIMIT_SHIFT) {
                        fatal("ERROR! tickshift = %i, less than "
                            "N_SAFE_DYNTRANS_LIMIT_SHIFT (%i)\n",
                            tickshift, N_SAFE_DYNTRANS_LIMIT_SHIFT);
                        exit(1);
                }
        }

        machine->ticks_till_next[n]   = 0;
        machine->ticks_reset_value[n] = 1 << tickshift;
        machine->tick_func[n]         = func;
        machine->tick_extra[n]        = extra;
        machine->tick_hz[n]           = hz;

        machine->n_tick_entries ++;
}


/*
 *  machine_statistics_init():
 *
 *  Initialize the parts of a machine struct that deal with instruction
 *  statistics gathering.
 *
 *  Note: The fname argument contains "flags:filename".
 */
void machine_statistics_init(struct machine *machine, char *fname)
{
        int n_fields = 0;
        char *pcolon = fname;
        char *mode = "a";       /*  Append by default  */

        machine->allow_instruction_combinations = 0;

        if (machine->statistics_fields != NULL) {
                fprintf(stderr, "Only one -s option is allowed.\n");
                exit(1);
        }

        machine->statistics_fields = malloc(MAX_STATISTICS_FIELDS + 1);
        machine->statistics_enabled = 1;

        while (*pcolon && *pcolon != ':')
                pcolon ++;

        if (*pcolon != ':') {
                fprintf(stderr, "The syntax for the -s option is:    "
                    "-s flags:filename\nYou omitted the flags. Run g"
                    "xemul -h for a list of available flags.\n");
                exit(1);
        }

        while (*fname != ':') {
                switch (*fname) {

                /*  Type flags:  */
                case 'v':
                case 'i':
                case 'p':
                        machine->statistics_fields[n_fields ++] = *fname;
                        if (n_fields >= MAX_STATISTICS_FIELDS) {
                                fprintf(stderr, "Internal error: Too many "
                                    "statistics fields used. Increase "
                                    "MAX_STATISTICS_FIELDS.\n");
                                exit(1);
                        }
                        machine->statistics_fields[n_fields] = '\0';
                        break;

                /*  Optional flags:  */
                case 'o':
                        mode = "w";
                        break;
                case 'd':
                        machine->statistics_enabled = 0;
                        break;

                default:fprintf(stderr, "Unknown flag '%c' used with the"
                            " -s option. Aborting.\n", *fname);
                        exit(1);
                }
                fname ++;
        }

        fname ++;       /*  point to the filename after the colon  */

        machine->statistics_filename = strdup(fname);
        machine->statistics_file = fopen(machine->statistics_filename, mode);
}


/*
 *  machine_dumpinfo():
 *
 *  Dumps info about a machine in some kind of readable format. (Used by
 *  the 'machine' debugger command.)
 */
void machine_dumpinfo(struct machine *m)
{
        int i;

        debug("serial nr: %i", m->serial_nr);
        if (m->nr_of_nics > 0)
                debug("  (nr of NICs: %i)", m->nr_of_nics);
        debug("\n");

        debug("memory: %i MB", m->physical_ram_in_mb);
        if (m->memory_offset_in_mb != 0)
                debug(" (offset by %i MB)", m->memory_offset_in_mb);
        if (m->random_mem_contents)
                debug(", randomized contents");
        if (m->dbe_on_nonexistant_memaccess)
                debug(", dbe_on_nonexistant_memaccess");
        debug("\n");

        if (!m->prom_emulation)
                debug("PROM emulation disabled\n");

        for (i=0; i<m->ncpus; i++)
                cpu_dumpinfo(m, m->cpus[i]);

        if (m->ncpus > 1)
                debug("Bootstrap cpu is nr %i\n", m->bootstrap_cpu);

        if (m->slow_serial_interrupts_hack_for_linux)
                debug("Using slow_serial_interrupts_hack_for_linux\n");

        if (m->use_x11) {
                debug("Using X11");
                if (m->x11_scaledown > 1)
                        debug(", scaledown %i", m->x11_scaledown);
                if (m->x11_scaleup > 1)
                        debug(", scaleup %i", m->x11_scaleup);
                if (m->x11_n_display_names > 0) {
                        for (i=0; i<m->x11_n_display_names; i++) {
                                debug(i? ", " : " (");
                                debug("\"%s\"", m->x11_display_names[i]);
                        }
                        debug(")");
                }
                debug("\n");
        }

        diskimage_dump_info(m);

        if (m->force_netboot)
                debug("Forced netboot\n");
}


/*
 *  dump_mem_string():
 *
 *  Dump the contents of emulated RAM as readable text.  Bytes that aren't
 *  readable are dumped in [xx] notation, where xx is in hexadecimal.
 *  Dumping ends after DUMP_MEM_STRING_MAX bytes, or when a terminating
 *  zero byte is found.
 */
#define DUMP_MEM_STRING_MAX     45
void dump_mem_string(struct cpu *cpu, uint64_t addr)
{
        int i;
        for (i=0; i<DUMP_MEM_STRING_MAX; i++) {
                unsigned char ch = '\0';

                cpu->memory_rw(cpu, cpu->mem, addr + i, &ch, sizeof(ch),
                    MEM_READ, CACHE_DATA | NO_EXCEPTIONS);
                if (ch == '\0')
                        return;
                if (ch >= ' ' && ch < 126)
                        debug("%c", ch);  
                else
                        debug("[%02x]", ch);
        }
}


/*
 *  store_byte():
 *
 *  Stores a byte in emulated ram. (Helper function.)
 */
void store_byte(struct cpu *cpu, uint64_t addr, uint8_t data)
{
        if ((addr >> 32) == 0)
                addr = (int64_t)(int32_t)addr;
        cpu->memory_rw(cpu, cpu->mem,
            addr, &data, sizeof(data), MEM_WRITE, CACHE_DATA);
}


/*
 *  store_string():
 *
 *  Stores chars into emulated RAM until a zero byte (string terminating
 *  character) is found. The zero byte is also copied.
 *  (strcpy()-like helper function, host-RAM-to-emulated-RAM.)
 */
void store_string(struct cpu *cpu, uint64_t addr, char *s)
{
        do {
                store_byte(cpu, addr++, *s);
        } while (*s++);
}


/*
 *  add_environment_string():
 *
 *  Like store_string(), but advances the pointer afterwards. The most
 *  obvious use is to place a number of strings (such as environment variable
 *  strings) after one-another in emulated memory.
 */
void add_environment_string(struct cpu *cpu, char *s, uint64_t *addr)
{
        store_string(cpu, *addr, s);
        (*addr) += strlen(s) + 1;
}


/*
 *  add_environment_string_dual():
 *
 *  Add "dual" environment strings, one for the variable name and one for the
 *  value, and update pointers afterwards.
 */
void add_environment_string_dual(struct cpu *cpu,
        uint64_t *ptrp, uint64_t *addrp, char *s1, char *s2)
{
        uint64_t ptr = *ptrp, addr = *addrp;

        store_32bit_word(cpu, ptr, addr);
        ptr += sizeof(uint32_t);
        if (addr != 0) {
                store_string(cpu, addr, s1);
                addr += strlen(s1) + 1;
        }
        store_32bit_word(cpu, ptr, addr);
        ptr += sizeof(uint32_t);
        if (addr != 0) {
                store_string(cpu, addr, s2);
                addr += strlen(s2) + 1;
        }

        *ptrp = ptr;
        *addrp = addr;
}


/*
 *  store_64bit_word():
 *
 *  Stores a 64-bit word in emulated RAM.  Byte order is taken into account.
 *  Helper function.
 */
int store_64bit_word(struct cpu *cpu, uint64_t addr, uint64_t data64)
{
        unsigned char data[8];
        if ((addr >> 32) == 0)
                addr = (int64_t)(int32_t)addr;
        data[0] = (data64 >> 56) & 255;
        data[1] = (data64 >> 48) & 255;
        data[2] = (data64 >> 40) & 255;
        data[3] = (data64 >> 32) & 255;
        data[4] = (data64 >> 24) & 255;
        data[5] = (data64 >> 16) & 255;
        data[6] = (data64 >> 8) & 255;
        data[7] = (data64) & 255;
        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[7]; data[7] = tmp;
                tmp = data[1]; data[1] = data[6]; data[6] = tmp;
                tmp = data[2]; data[2] = data[5]; data[5] = tmp;
                tmp = data[3]; data[3] = data[4]; data[4] = tmp;
        }
        return cpu->memory_rw(cpu, cpu->mem,
            addr, data, sizeof(data), MEM_WRITE, CACHE_DATA);
}


/*
 *  store_32bit_word():
 *
 *  Stores a 32-bit word in emulated RAM.  Byte order is taken into account.
 *  (This function takes a 64-bit word as argument, to suppress some
 *  warnings, but only the lowest 32 bits are used.)
 */
int store_32bit_word(struct cpu *cpu, uint64_t addr, uint64_t data32)
{
        unsigned char data[4];

        /*  TODO: REMOVE THIS once everything is more stable!  */
        if (cpu->machine->arch == ARCH_MIPS && (addr >> 32) == 0)
                addr = (int64_t)(int32_t)addr;

        data[0] = (data32 >> 24) & 255;
        data[1] = (data32 >> 16) & 255;
        data[2] = (data32 >> 8) & 255;
        data[3] = (data32) & 255;
        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[3]; data[3] = tmp;
                tmp = data[1]; data[1] = data[2]; data[2] = tmp;
        }
        return cpu->memory_rw(cpu, cpu->mem,
            addr, data, sizeof(data), MEM_WRITE, CACHE_DATA);
}


/*
 *  store_16bit_word():
 *
 *  Stores a 16-bit word in emulated RAM.  Byte order is taken into account.
 *  (This function takes a 64-bit word as argument, to suppress some
 *  warnings, but only the lowest 16 bits are used.)
 */
int store_16bit_word(struct cpu *cpu, uint64_t addr, uint64_t data16)
{
        unsigned char data[2];

        /*  TODO: REMOVE THIS once everything is more stable!  */
        if (cpu->machine->arch == ARCH_MIPS && (addr >> 32) == 0)
                addr = (int64_t)(int32_t)addr;

        data[0] = (data16 >> 8) & 255;
        data[1] = (data16) & 255;
        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[1]; data[1] = tmp;
        }
        return cpu->memory_rw(cpu, cpu->mem,
            addr, data, sizeof(data), MEM_WRITE, CACHE_DATA);
}


/*
 *  store_buf():
 *
 *  memcpy()-like helper function, from host RAM to emulated RAM.
 */
void store_buf(struct cpu *cpu, uint64_t addr, char *s, size_t len)
{
        size_t psize = 1024;    /*  1024 256 64 16 4 1  */

        /*  TODO: REMOVE THIS once everything is more stable!  */
        if (cpu->machine->arch == ARCH_MIPS && (addr >> 32) == 0)
                addr = (int64_t)(int32_t)addr;

        while (len != 0) {
                if ((addr & (psize-1)) == 0) {
                        while (len >= psize) {
                                cpu->memory_rw(cpu, cpu->mem, addr,
                                    (unsigned char *)s, psize, MEM_WRITE,
                                    CACHE_DATA);
                                addr += psize;
                                s += psize;
                                len -= psize;
                        }
                }
                psize >>= 2;
        }

        while (len-- != 0)
                store_byte(cpu, addr++, *s++);
}


/*
 *  store_pointer_and_advance():
 *
 *  Stores a 32-bit or 64-bit pointer in emulated RAM, and advances the
 *  target address. (Useful for e.g. ARCBIOS environment initialization.)
 */
void store_pointer_and_advance(struct cpu *cpu, uint64_t *addrp,
        uint64_t data, int flag64)
{
        uint64_t addr = *addrp;
        if (flag64) {
                store_64bit_word(cpu, addr, data);
                addr += 8;
        } else {
                store_32bit_word(cpu, addr, data);
                addr += 4;
        }
        *addrp = addr;
}


/*
 *  load_64bit_word():
 *
 *  Helper function. Emulated byte order is taken into account.
 */
uint64_t load_64bit_word(struct cpu *cpu, uint64_t addr)
{
        unsigned char data[8];

        cpu->memory_rw(cpu, cpu->mem,
            addr, data, sizeof(data), MEM_READ, CACHE_DATA);

        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[7]; data[7] = tmp;
                tmp = data[1]; data[1] = data[6]; data[6] = tmp;
                tmp = data[2]; data[2] = data[5]; data[5] = tmp;
                tmp = data[3]; data[3] = data[4]; data[4] = tmp;
        }

        return
            ((uint64_t)data[0] << 56) + ((uint64_t)data[1] << 48) +
            ((uint64_t)data[2] << 40) + ((uint64_t)data[3] << 32) +
            ((uint64_t)data[4] << 24) + ((uint64_t)data[5] << 16) +
            ((uint64_t)data[6] << 8) + (uint64_t)data[7];
}


/*
 *  load_32bit_word():
 *
 *  Helper function. Emulated byte order is taken into account.
 */
uint32_t load_32bit_word(struct cpu *cpu, uint64_t addr)
{
        unsigned char data[4];

        /*  TODO: REMOVE THIS once everything is more stable!  */
        if (cpu->machine->arch == ARCH_MIPS && (addr >> 32) == 0)
                addr = (int64_t)(int32_t)addr;

        cpu->memory_rw(cpu, cpu->mem,
            addr, data, sizeof(data), MEM_READ, CACHE_DATA);

        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[3]; data[3] = tmp;
                tmp = data[1]; data[1] = data[2]; data[2] = tmp;
        }

        return (data[0] << 24) + (data[1] << 16) + (data[2] << 8) + data[3];
}


/*
 *  load_16bit_word():
 *
 *  Helper function. Emulated byte order is taken into account.
 */
uint16_t load_16bit_word(struct cpu *cpu, uint64_t addr)
{
        unsigned char data[2];

        /*  TODO: REMOVE THIS once everything is more stable!  */
        if (cpu->machine->arch == ARCH_MIPS && (addr >> 32) == 0)
                addr = (int64_t)(int32_t)addr;

        cpu->memory_rw(cpu, cpu->mem,
            addr, data, sizeof(data), MEM_READ, CACHE_DATA);

        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[1]; data[1] = tmp;
        }

        return (data[0] << 8) + data[1];
}


/*
 *  store_64bit_word_in_host():
 *
 *  Stores a 64-bit word in the _host's_ RAM.  Emulated byte order is taken
 *  into account.  This is useful when building structs in the host's RAM
 *  which will later be copied into emulated RAM.
 */
void store_64bit_word_in_host(struct cpu *cpu,
        unsigned char *data, uint64_t data64)
{
        data[0] = (data64 >> 56) & 255;
        data[1] = (data64 >> 48) & 255;
        data[2] = (data64 >> 40) & 255;
        data[3] = (data64 >> 32) & 255;
        data[4] = (data64 >> 24) & 255;
        data[5] = (data64 >> 16) & 255;
        data[6] = (data64 >> 8) & 255;
        data[7] = (data64) & 255;
        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[7]; data[7] = tmp;
                tmp = data[1]; data[1] = data[6]; data[6] = tmp;
                tmp = data[2]; data[2] = data[5]; data[5] = tmp;
                tmp = data[3]; data[3] = data[4]; data[4] = tmp;
        }
}


/*
 *  store_32bit_word_in_host():
 *
 *  See comment for store_64bit_word_in_host().
 *
 *  (Note:  The data32 parameter is a uint64_t. This is done to suppress
 *  some warnings.)
 */
void store_32bit_word_in_host(struct cpu *cpu,
        unsigned char *data, uint64_t data32)
{
        data[0] = (data32 >> 24) & 255;
        data[1] = (data32 >> 16) & 255;
        data[2] = (data32 >> 8) & 255;
        data[3] = (data32) & 255;
        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[3]; data[3] = tmp;
                tmp = data[1]; data[1] = data[2]; data[2] = tmp;
        }
}


/*
 *  store_16bit_word_in_host():
 *
 *  See comment for store_64bit_word_in_host().
 */
void store_16bit_word_in_host(struct cpu *cpu,
        unsigned char *data, uint16_t data16)
{
        data[0] = (data16 >> 8) & 255;
        data[1] = (data16) & 255;
        if (cpu->byte_order == EMUL_LITTLE_ENDIAN) {
                int tmp = data[0]; data[0] = data[1]; data[1] = tmp;
        }
}


/*
 *  machine_setup():
 *
 *  This (rather large) function initializes memory, registers, and/or devices
 *  required by specific machine emulations.
 */
void machine_setup(struct machine *machine)
{
        struct memory *mem;
        struct machine_entry *me;

        /*  Abreviation:  :-)  */
        struct cpu *cpu = machine->cpus[machine->bootstrap_cpu];

        machine->bootdev_id = diskimage_bootdev(machine,
            &machine->bootdev_type);

        mem = cpu->mem;
        machine->machine_name = NULL;

        /*  TODO: Move this somewhere else?  */
        if (machine->boot_string_argument == NULL) {
                switch (machine->machine_type) {
                case MACHINE_ARC:
                        machine->boot_string_argument = "-aN";
                        break;
                case MACHINE_CATS:
                        machine->boot_string_argument = "-A";
                        break;
                case MACHINE_PMAX:
                        machine->boot_string_argument = "-a";
                        break;
                default:
                        /*  Important, because boot_string_argument should
                            not be set to NULL:  */
                        machine->boot_string_argument = "";
                }
        }


        /*
         *  If the machine has a setup function in src/machines/machine_*.c
         *  then use that one, otherwise use the old hardcoded stuff here:
         */

        me = first_machine_entry;
        while (me != NULL) {
                if (machine->machine_type == me->machine_type &&
                    me->setup != NULL) {
                        me->setup(machine, cpu);
                        break;
                }
                me = me->next;
        }

        if (me == NULL) {
                fatal("Unknown emulation type %i\n", machine->machine_type);
                exit(1);
        }

        if (machine->machine_name != NULL)
                debug("machine: %s", machine->machine_name);

        if (machine->emulated_hz > 0)
                debug(" (%.2f MHz)", (float)machine->emulated_hz / 1000000);
        debug("\n");

        if (machine->bootstr != NULL) {
                debug("bootstring%s: %s", (machine->bootarg!=NULL &&
                    strlen(machine->bootarg) >= 1)? "(+bootarg)" : "",
                    machine->bootstr);
                if (machine->bootarg != NULL && strlen(machine->bootarg) >= 1)
                        debug(" %s", machine->bootarg);
                debug("\n");
        }

        if (!machine->stable)
                fatal("!\n!  NOTE: This machine type is not implemented well"
                    " enough yet to run\n!  any real-world code!"
                    " (At least, it hasn't been verified to do so.)\n!\n"
                    "!  Please read the GXemul documentation for information"
                    " about which\n!  machine types that actually work.\n!\n");
}


/*
 *  machine_memsize_fix():
 *
 *  Sets physical_ram_in_mb (if not already set), and memory_offset_in_mb,
 *  depending on machine type.
 */
void machine_memsize_fix(struct machine *m)
{
        if (m == NULL) {
                fatal("machine_defaultmemsize(): m == NULL?\n");
                exit(1);
        }

        if (m->physical_ram_in_mb == 0) {
                struct machine_entry *me = first_machine_entry;
                while (me != NULL) {
                        if (m->machine_type == me->machine_type &&
                            me->set_default_ram != NULL) {
                                me->set_default_ram(m);
                                break;
                        }
                        me = me->next;
                }
        }

        /*  Special hack for hpcmips machines:  */
        if (m->machine_type == MACHINE_HPCMIPS) {
                m->dbe_on_nonexistant_memaccess = 0;
        }

        /*  Special SGI memory offsets:  (TODO: move this somewhere else)  */
        if (m->machine_type == MACHINE_SGI) {
                switch (m->machine_subtype) {
                case 20:
                case 22:
                case 24:
                case 26:
                        m->memory_offset_in_mb = 128;
                        break;
                case 28:
                case 30:
                        m->memory_offset_in_mb = 512;
                        break;
                }
        }

        if (m->physical_ram_in_mb == 0)
                m->physical_ram_in_mb = DEFAULT_RAM_IN_MB;
}


/*
 *  machine_default_cputype():
 *
 *  Sets m->cpu_name, if it isn't already set, depending on the machine type.
 */
void machine_default_cputype(struct machine *m)
{
        struct machine_entry *me;

        if (m == NULL) {
                fatal("machine_default_cputype(): m == NULL?\n");
                exit(1);
        }

        /*  Already set? Then return.  */
        if (m->cpu_name != NULL)
                return;

        me = first_machine_entry;
        while (me != NULL) {
                if (m->machine_type == me->machine_type &&
                    me->set_default_cpu != NULL) {
                        me->set_default_cpu(m);
                        break;
                }
                me = me->next;
        }

        if (m->cpu_name == NULL) {
                fprintf(stderr, "machine_default_cputype(): no default"
                    " cpu for machine type %i subtype %i\n",
                    m->machine_type, m->machine_subtype);
                exit(1);
        }
}


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


/*
 *  machine_run():
 *
 *  Run one or more instructions on all CPUs in this machine. (Usually,
 *  around N_SAFE_DYNTRANS_LIMIT instructions will be run by the dyntrans
 *  system.)
 *
 *  Return value is 1 if any CPU in this machine is still running,
 *  or 0 if all CPUs are stopped.
 */
int machine_run(struct machine *machine)
{
        struct cpu **cpus = machine->cpus;
        int ncpus = machine->ncpus, cpu0instrs = 0, i, te;

        for (i=0; i<ncpus; i++) {
                if (cpus[i]->running) {
                        int instrs_run = cpus[i]->run_instr(cpus[i]);
                        if (i == 0)
                                cpu0instrs += instrs_run;
                }
        }

        /*
         *  Hardware 'ticks':  (clocks, interrupt sources...)
         *
         *  Here, cpu0instrs is the number of instructions executed on cpu0.
         *
         *  TODO: This should be redesigned into some "mainbus" stuff instead!
         */

        machine->ninstrs += cpu0instrs;

        for (te=0; te<machine->n_tick_entries; te++) {
                machine->ticks_till_next[te] -= cpu0instrs;
                if (machine->ticks_till_next[te] <= 0) {
                        while (machine->ticks_till_next[te] <= 0) {
                                machine->ticks_till_next[te] +=
                                    machine->ticks_reset_value[te];
                        }

                        machine->tick_func[te](cpus[0],
                            machine->tick_extra[te]);
                }
        }

        /*  Is any CPU still alive?  */
        for (i=0; i<ncpus; i++)
                if (cpus[i]->running)
                        return 1;

        return 0;
}


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


/*
 *  machine_entry_new():
 *
 *  This function creates a new machine_entry struct, and fills it with some
 *  valid data; it is up to the caller to add additional data that weren't
 *  passed as arguments to this function, such as alias names and machine
 *  subtypes.
 */
struct machine_entry *machine_entry_new(const char *name, int arch,
        int oldstyle_type)
{
        struct machine_entry *me;

        me = malloc(sizeof(struct machine_entry));
        if (me == NULL) {
                fprintf(stderr, "machine_entry_new(): out of memory (1)\n");
                exit(1);
        }

        memset(me, 0, sizeof(struct machine_entry));

        me->name = name;
        me->arch = arch;
        me->machine_type = oldstyle_type;
        me->n_aliases = 0;
        me->aliases = NULL;
        me->n_subtypes = 0;
        me->setup = NULL;

        return me;
}


/*
 *  machine_entry_add_alias():
 *
 *  This function adds an "alias" to a machine entry.
 */
void machine_entry_add_alias(struct machine_entry *me, const char *name)
{
        me->n_aliases ++;
        me->aliases = realloc(me->aliases, sizeof(char *) * me->n_aliases);
        if (me->aliases == NULL) {
                fprintf(stderr, "out of memory\n");
                exit(1);
        }

        me->aliases[me->n_aliases - 1] = (char *) name;
}


/*
 *  machine_entry_add_subtype():
 *
 *  This function adds a subtype to a machine entry. The argument list after
 *  oldstyle_subtype is a list of one or more char *, followed by NULL. E.g.:
 *
 *      machine_entry_add_subtype(me, "Machine X", MACHINE_X,
 *          "machine-x", "x", NULL);
 */
void machine_entry_add_subtype(struct machine_entry *me, const char *name,
        int oldstyle_subtype, ...)
{
        va_list argp;
        struct machine_entry_subtype *mes;

        /*  Allocate a new subtype struct:  */
        mes = malloc(sizeof(struct machine_entry_subtype));
        if (mes == NULL) {
                fprintf(stderr, "machine_entry_subtype_new(): out "
                    "of memory (1)\n");
                exit(1);
        }

        /*  Add the subtype to the machine entry:  */
        me->n_subtypes ++;
        me->subtype = realloc(me->subtype, sizeof(struct
            machine_entry_subtype *) * me->n_subtypes);
        if (me->subtype == NULL) {
                fprintf(stderr, "out of memory\n");
                exit(1);
        }
        me->subtype[me->n_subtypes - 1] = mes;

        /*  Fill the struct with subtype data:  */
        memset(mes, 0, sizeof(struct machine_entry_subtype));
        mes->name = name;
        mes->machine_subtype = oldstyle_subtype;

        /*  ... and all aliases:  */
        mes->n_aliases = 0;
        mes->aliases = NULL;

        va_start(argp, oldstyle_subtype);

        for (;;) {
                char *s = va_arg(argp, char *);
                if (s == NULL)
                        break;

                mes->n_aliases ++;
                mes->aliases = realloc(mes->aliases, sizeof(char *) *
                    mes->n_aliases);
                if (mes->aliases == NULL) {
                        fprintf(stderr, "out of memory\n");
                        exit(1);
                }

                mes->aliases[mes->n_aliases - 1] = s;
        }

        va_end(argp);
}


/*
 *  machine_entry_register():
 *
 *  Inserts a new machine_entry into the machine entries list.
 */
void machine_entry_register(struct machine_entry *me, int arch)
{
        struct machine_entry *prev, *next;

        /*  Only insert it if the architecture is implemented in this
            emulator configuration:  */
        if (cpu_family_ptr_by_number(arch) == NULL)
                return;

        prev = NULL;
        next = first_machine_entry;

        for (;;) {
                if (next == NULL)
                        break;
                if (strcasecmp(me->name, next->name) < 0)
                        break;

                prev = next;
                next = next->next;
        }

        if (prev != NULL)
                prev->next = me;
        else
                first_machine_entry = me;
        me->next = next;
}


/*
 *  machine_list_available_types_and_cpus():
 *
 *  List all available machine types (for example when running the emulator
 *  with just -H as command line argument).
 */
void machine_list_available_types_and_cpus(void)
{
        struct machine_entry *me;
        int iadd = DEBUG_INDENTATION * 2;

        debug("Available CPU types:\n\n");

        debug_indentation(iadd);
        cpu_list_available_types();
        debug_indentation(-iadd);  

        debug("\nMost of the CPU types are bogus, and not really implemented."
            " The main effect of\nselecting a specific CPU type is to choose "
            "what kind of 'id' it will have.\n\nAvailable machine types (with "
            "aliases) and their subtypes:\n\n");

        debug_indentation(iadd);
        me = first_machine_entry;

        if (me == NULL)
                fatal("No machines defined!\n");

        while (me != NULL) {
                int i, j, iadd = DEBUG_INDENTATION;

                debug("%s [%s] (", me->name,
                    cpu_family_ptr_by_number(me->arch)->name);
                for (i=0; i<me->n_aliases; i++)
                        debug("%s\"%s\"", i? ", " : "", me->aliases[i]);
                debug(")\n");

                debug_indentation(iadd);
                for (i=0; i<me->n_subtypes; i++) {
                        struct machine_entry_subtype *mes;
                        mes = me->subtype[i];
                        debug("- %s", mes->name);
                        debug(" (");
                        for (j=0; j<mes->n_aliases; j++)
                                debug("%s\"%s\"", j? ", " : "",
                                    mes->aliases[j]);
                        debug(")\n");
                }
                debug_indentation(-iadd);

                me = me->next;
        }
        debug_indentation(-iadd);

        debug("\nMost of the machine types are bogus too. Please read the "
            "GXemul documentation\nfor information about which machine types "
            "that actually work. Use the alias\nwhen selecting a machine type "
            "or subtype, not the real name.\n");

#ifdef UNSTABLE_DEVEL
        debug("\n");

        useremul_list_emuls();
        debug("Userland emulation works for programs with the complexity"
            " of Hello World,\nbut not much more.\n");
#endif
}


/*
 *  machine_init():
 *
 *  This function should be called before any other machine_*() function
 *  is used.  automachine_init() registers all machines in src/machines/.
 */
void machine_init(void)
{
        if (first_machine_entry != NULL) {
                fatal("machine_init(): already called?\n");
                exit(1);
        }

        automachine_init();
}
