usr/src/pgrm/dbx/sun.c

/*
 * Copyright (c) 1983 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that: (1) source distributions retain this entire copyright
 * notice and comment, and (2) distributions including binaries display
 * the following acknowledgement:  ``This product includes software
 * developed by the University of California, Berkeley and its contributors''
 * in the documentation or other materials provided with the distribution
 * and in all advertising materials mentioning features or use of this
 * software. Neither the name of the University nor the names of its
 * contributors may be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#ifndef lint
static char sccsid[] = "@(#)sun.c       5.2 (Berkeley) 6/1/90";
#endif /* not lint */

/*
 * Target machine dependent stuff.
 */

#include "defs.h"
#include "machine.h"
#include "process.h"
#include "runtime.h"
#include "events.h"
#include "main.h"
#include "symbols.h"
#include "source.h"
#include "mappings.h"
#include "object.h"
#include "tree.h"
#include "eval.h"
#include "keywords.h"
#include "ops.h"

#ifndef public
typedef unsigned int Address;
typedef unsigned char Byte;
typedef unsigned int Word;

/*
 * On the 68000, the pc isn't in a register, but we make believe
 * so there's one more register.
 *
 * Note that there's also no argument pointer, this means code
 * involving "ARGP" should always be #ifdef'd.
 *
 * The address corresponding to the beginning of a function is recorded
 * as the address + FUNCOFFSET (skip the link instruction so that
 * local information is available).
 */

#define NREG 17

#define FRP 14
#define STKP 15
#define PROGCTR 16

#define CALL_RETADDR    0x800c          /* Return address for 'call' command */
#define FUNCOFFSET 4

#ifdef sun
#    define CODESTART 0x8000
#else /* IRIS */
#   define CODESTART 0x1000
#endif

#define optab_init()

#define BITSPERBYTE 8
#define BITSPERWORD (BITSPERBYTE * sizeof(Word))

/*
 * This magic macro enables us to look at the process' registers
 * in its user structure.
 */

#define regloc(reg)     (ctob(UPAGES) + (sizeof(Word) * ((reg) - PC)) - 10)

#include "source.h"
#include "symbols.h"
#include <signal.h>
#include <sys/param.h>
#include <sys/dir.h>
#include <machine/psl.h>
#include <machine/pte.h>
#include <sys/user.h>
#undef DELETE /* XXX */
#include <sys/vm.h>
#include <machine/reg.h>

Address pc;
Address prtaddr;

#endif

/*
 * Indices into u. for use in collecting registers values.
 */
public int rloc[] ={
#ifdef sun
    R0, R1, R2, R3, R4, R5, R6, R7, AR0, AR1, AR2, AR3, AR4, AR5, AR6, AR7, PC
#else /* IRIS */
    R0, R1, R2, R3, R4, R5, R6, R7, AR0, AR1, AR2, AR3, AR4, AR5, AR6, AR7, 16
#endif
};

private Address printop();

/*
 * Decode and print the instructions within the given address range.
 */

public printinst(lowaddr, highaddr)
Address lowaddr;
Address highaddr;
{
    register Address addr;

    for (addr = lowaddr; addr <= highaddr; ) {
        addr = printop(addr);
    }
    prtaddr = addr;
}

/*
 * Another approach:  print n instructions starting at the given address.
 */

public printninst(count, addr)
int count;
Address addr;
{
    register Integer i;
    register Address newaddr;

    if (count <= 0) {
        error("non-positive repetition count");
    } else {
        newaddr = addr;
        for (i = 0; i < count; i++) {
            newaddr = printop(newaddr);
        }
        prtaddr = newaddr;
    }
}

/*
 * Print the contents of the addresses within the given range
 * according to the given format.
 */

typedef struct {
    String name;
    String printfstring;
    int length;
} Format;

private Format fmt[] = {
    { "d", " %d", sizeof(short) },
    { "D", " %ld", sizeof(long) },
    { "o", " %o", sizeof(short) },
    { "O", " %lo", sizeof(long) },
    { "x", " %04x", sizeof(short) },
    { "X", " %08x", sizeof(long) },
    { "b", " \\%o", sizeof(char) },
    { "c", " '%c'", sizeof(char) },
    { "s", "%c", sizeof(char) },
    { "f", " %f", sizeof(float) },
    { "g", " %g", sizeof(double) },
    { nil, nil, 0 }
};

private Format *findformat(s)
String s;
{
    register Format *f;

    f = &fmt[0];
    while (f->name != nil and not streq(f->name, s)) {
        ++f;
    }
    if (f->name == nil) {
        error("bad print format \"%s\"", s);
    }
    return f;
}

/*
 * Retrieve and print out the appropriate data in the given format.
 * Floats have to be handled specially to allow the compiler to
 * convert them to doubles when passing to printf.
 */

private printformat (f, addr)
Format *f;
Address addr;
{
    union {
        char charv;
        short shortv;
        int intv;
        float floatv;
        double doublev;
    } value;

    value.intv = 0;
    dread(&value, addr, f->length);
    if (streq(f->name, "f")) {
        printf(f->printfstring, value.floatv);
    } else {
        printf(f->printfstring, value);
    }
}

public Address printdata(lowaddr, highaddr, format)
Address lowaddr;
Address highaddr;
String format;
{
    int n;
    register Address addr;
    Format *f;

    if (lowaddr > highaddr) {
        error("first address larger than second");
    }
    f = findformat(format);
    n = 0;
    for (addr = lowaddr; addr <= highaddr; addr += f->length) {
        if (n == 0) {
            printf("%08x: ", addr);
        }
        printformat(f, addr);
        ++n;
        if (n >= (16 div f->length)) {
            printf("\n");
            n = 0;
        }
    }
    if (n != 0) {
        printf("\n");
    }
    prtaddr = addr;
    return addr;
}

/*
 * The other approach is to print n items starting with a given address.
 */

public printndata(count, startaddr, format)
int count;
Address startaddr;
String format;
{
    int i, n;
    Address addr;
    Format *f;
    Boolean isstring;
    char c;

    if (count <= 0) {
        error("non-positive repetition count");
    }
    f = findformat(format);
    isstring = (Boolean) streq(f->name, "s");
    n = 0;
    addr = startaddr;
    for (i = 0; i < count; i++) {
        if (n == 0) {
            printf("%08x: ", addr);
        }
        if (isstring) {
            printf("\"");
            dread(&c, addr, sizeof(char));
            while (c != '\0') {
                printchar(c);
                ++addr;
                dread(&c, addr, sizeof(char));
            }
            printf("\"\n");
            n = 0;
            addr += sizeof(String);
        } else {
            printformat(f, addr);
            ++n;
            if (n >= (16 div f->length)) {
                printf("\n");
                n = 0;
            }
            addr += f->length;
        }
    }
    if (n != 0) {
        printf("\n");
    }
    prtaddr = addr;
}

/*
 * Print out a value according to the given format.
 */

public printvalue(v, format)
long v;
String format;
{
    Format *f;
    char *p, *q;

    f = findformat(format);
    if (streq(f->name, "s")) {
        putchar('"');
        p = (char *) &v;
        q = p + sizeof(v);
        while (p < q) {
            printchar(*p);
            ++p;
        }
        putchar('"');
    } else {
        printf(f->printfstring, v);
    }
    putchar('\n');
}

/*
 * Print out an execution time error.
 * Assumes the source position of the error has been calculated.
 *
 * Have to check if the -r option was specified; if so then
 * the object file information hasn't been read in yet.
 */

public printerror()
{
    extern Integer sys_nsig;
    extern String sys_siglist[];
    integer err;

    if (isfinished(process)) {
        err = exitcode(process);
        if (err == 0) {
            printf("\"%s\" terminated normally\n", objname);
        } else {
            printf("\"%s\" terminated abnormally (exit code %d)\n",
                objname, err
            );
        }
        erecover();
    }
    err = errnum(process);
    putchar('\n');
    printsig(err);
    putchar(' ');
    printloc();
    putchar('\n');
    if (curline > 0) {
        printlines(curline, curline);
    } else {
        printinst(pc, pc);
    }
    erecover();
}

/*
 * Print out a signal.
 */

private String illinames[] = {
    "reserved addressing fault",
    "privileged instruction fault",
    "reserved operand fault"
};

private String fpenames[] = {
    nil,
    "integer overflow trap",
    "integer divide by zero trap",
    "floating overflow trap",
    "floating/decimal divide by zero trap",
    "floating underflow trap",
    "decimal overflow trap",
    "subscript out of range trap",
    "floating overflow fault",
    "floating divide by zero fault",
    "floating underflow fault"
};

public printsig (signo)
integer signo;
{
    integer code;

    if (signo < 0 or signo > sys_nsig) {
        printf("[signal %d]", signo);
    } else {
        printf("%s", sys_siglist[signo]);
    }
    code = errcode(process);
    if (signo == SIGILL) {
        if (code >= 0 and code < sizeof(illinames) / sizeof(illinames[0])) {
            printf(" (%s)", illinames[code]);
        }
    } else if (signo == SIGFPE) {
        if (code > 0 and code < sizeof(fpenames) / sizeof(fpenames[0])) {
            printf(" (%s)", fpenames[code]);
        }
    }
}

/*
 * Note the termination of the program.  We do this so as to avoid
 * having the process exit, which would make the values of variables
 * inaccessible.  We do want to flush all output buffers here,
 * otherwise it'll never get done.
 */

public endprogram()
{
    Integer exitcode;

    stepto(nextaddr(pc, true));
    printnews();
    exitcode = argn(1, nil);
    if (exitcode != 0) {
        printf("\nexecution completed (exit code %d)\n", exitcode);
    } else {
        printf("\nexecution completed\n");
    }
    getsrcpos();
    erecover();
}

/*
 * Single step the machine a source line (or instruction if "inst_tracing"
 * is true).  If "isnext" is true, skip over procedure calls.
 */

private Address getcall();

public dostep(isnext)
Boolean isnext;
{
    register Address addr;
    register Lineno line;
    String filename;
    Address startaddr;

    startaddr = pc;
    addr = nextaddr(pc, isnext);
    if (not inst_tracing and nlhdr.nlines != 0) {
        line = linelookup(addr);
        while (line == 0) {
            addr = nextaddr(addr, isnext);
            line = linelookup(addr);
        }
        curline = line;
    } else {
        curline = 0;
    }
    stepto(addr);
    filename = srcfilename(addr);
    setsource(filename);
}

typedef short Bpinst;

extern Bpinst BP_OP;
#ifdef sun
        asm("_BP_OP: trap #15");
#else /* IRIS */
        asm("_BP_OP: trap #1");
#endif

#define BP_ERRNO    SIGTRAP     /* signal received at a breakpoint */

/*
 * Setting a breakpoint at a location consists of saving
 * the word at the location and poking a BP_OP there.
 *
 * We save the locations and words on a list for use in unsetting.
 */

typedef struct Savelist *Savelist;

struct Savelist {
    Address location;
    Bpinst save;
    short refcount;
    Savelist link;
};

private Savelist savelist;

/*
 * Set a breakpoint at the given address.  Only save the word there
 * if it's not already a breakpoint.
 */

public setbp(addr)
Address addr;
{
    Bpinst w, save;
    register Savelist newsave, s;

    for (s = savelist; s != nil; s = s->link) {
        if (s->location == addr) {
            s->refcount++;
            return;
        }
    }
    iread(&save, addr, sizeof(save));
    newsave = new(Savelist);
    newsave->location = addr;
    newsave->save = save;
    newsave->refcount = 1;
    newsave->link = savelist;
    savelist = newsave;
    w = BP_OP;
    iwrite(&w, addr, sizeof(w));
}

/*
 * Unset a breakpoint; unfortunately we have to search the SAVELIST
 * to find the saved value.  The assumption is that the SAVELIST will
 * usually be quite small.
 */

public unsetbp(addr)
Address addr;
{
    register Savelist s, prev;

    prev = nil;
    for (s = savelist; s != nil; s = s->link) {
        if (s->location == addr) {
            iwrite(&s->save, addr, sizeof(s->save));
            s->refcount--;
            if (s->refcount == 0) {
                if (prev == nil) {
                    savelist = s->link;
                } else {
                    prev->link = s->link;
                }
                dispose(s);
            }
            return;
        }
        prev = s;
    }
    panic("unsetbp: couldn't find address %d", addr);
}

/*
 * Instruction decoding routines for 68000, derived from adb.
 *
 * The shared boolean variable "printing" is true if the decoded
 * instruction is to be printed, false if not.  In either case,
 * the address of the next instruction after the given one is returned.
 */

private Boolean printing;
private Boolean following;
private Boolean followcalls;
private Address instaddr;

#define instread(var) \
{ \
    iread(&var, instaddr, sizeof(var)); \
    instaddr += sizeof(var); \
}

private Optab *decode(inst, addr)
Word inst;
Address addr;
{
    register Optab *o;

    o = &optab[0];
    while (o->mask != 0 and (inst&o->mask) != o->match) {
        ++o;
    }
    return o;
}

private Address printop(addr)
Address addr;
{
    Optab *o;
    short inst;

    printf("%08x  ", addr);
    iread(&inst, addr, sizeof(inst));
    o = decode(inst, addr);
    if (o->mask == 0) {
        printf("\tbadop");
        instaddr = addr + sizeof(inst);
    } else {
        printing = true;
        following = false;
        instaddr = addr + sizeof(inst);
        (*o->opfun)(inst, o->farg);
        printing = false;
    }
    printf("\n");
    return instaddr;
}

/*
 * Quickly find the return address of the current procedure or function
 * while single stepping.  Just get the word pointed at by sp.
 */

private Address currtnaddr ()
{
    Address retaddr;

    dread(&retaddr, reg(STKP), sizeof(retaddr));
    return retaddr;
}

/*
 * Print out the effective address for the given parameters.
 */

private printea(mode, reg, size)
long mode, reg;
int size;
{
    long index, disp;
    static char *aregs[] = { "a0", "a1", "a2", "a3", "a4", "a5", "a6", "sp" };
    Byte b;
    short w;
    long l;

    switch ((int)(mode)) {
        case 0:
            if (printing) {
                printf("d%D", reg);
            }
            break;

        case 1:
            if (printing) {
                printf("%s", aregs[reg]);
            }
            break;

        case 2:
            if (printing) {
                printf("%s@", aregs[reg]);
            }
            break;

        case 3:
            if (printing) {
                printf("%s@+", aregs[reg]);
            }
            break;

        case 4:
            if (printing) {
                printf("%s@-", aregs[reg]);
            }
            break;

        case 5:
            instread(w);
            if (printing) {
                printf("%s@(%D)", aregs[reg], w);
            }
            break;

        case 6:
            instread(w);
            if (printing) {
                index = w;
                disp = (char)(index&0377);
                printf("%s@(%d,%c%D:%c)", aregs[reg], disp,
                    (index&0100000)?'a':'d',(index>>12)&07,
                    (index&04000)?'l':'w');
            }
            break;

        case 7:
            switch ((int)(reg)) {
                case 0:
                    instread(w);
                    if (printing) {
                        index = w;
                        psymoff(index);
                    }
                    break;

                case 1:
                    instread(l);
                    if (printing) {
                        index = l;
                        psymoff(index);
                    }
                    break;

                case 2:
                    instread(w);
                    if (printing) {
                        disp = w;
                        psymoff(disp + instaddr);
                    }
                    break;

                case 3:
                    instread(w);
                    if (printing) {
                        index = w;
                        disp = (char)(index&0377);
                        printf("pc@(%D,%c%D:%c)", disp,
                            (index&0100000)?'a':'d',(index>>12)&07,
                            (index&04000)?'l':'w');
                    }
                    break;

                case 4:
                    switch (size) {
                        case sizeof(b):
                            instread(w);
                            index = (w&0xff);
                            break;

                        case sizeof(w):
                            instread(w);
                            index = w;
                            break;

                        case sizeof(l):
                            instread(l);
                            index = l;
                            break;

                        default:
                            if (printing) {
                                printf("unexpected size %d in printea\n", size);
                            }
                            instread(l);
                            index = l;
                            break;
                    }
                    if (printing) {
                        printf(IMDF, index);
                    }
                    break;

                default:
                    if (printing) {
                        printf("???");
                    }
                    break;
            }
            break;

        default:
            if (printing) {
                printf("???");
            }
            break;
    }
}

private printEA(ea, size)
long ea;
int size;
{
    printea((ea>>3)&07, ea&07, size);
}

private mapsize(inst)
register long inst;
{
    int m;

    inst >>= 6;
    inst &= 03;
    switch (inst) {
        case 0:
            m = 1;
            break;

        case 1:
            m = 2;
            break;

        case 2:
            m = 4;
            break;

        default:
            m = -1;
            break;
    }
    return m;
}

private char suffix(size)
int size;
{
    char c;

    switch (size) {
        case 1:
            c = 'b';
            break;

        case 2:
            c = 'w';
            break;

        case 4:
            c = 'l';
            break;

        default:
            panic("bad size %d in suffix", size);
    }
    return c;
}

/*
 * Print an address offset.  Eventually this should attempt to be symbolic,
 * but for now its just printed in hex.
 */

private psymoff (off)
Word off;
{
    Symbol f;

    f = whatblock((Address) (off + FUNCOFFSET));
    if (codeloc(f) == off + FUNCOFFSET) {
        printf("%s", symname(f));
    } else {
        printf("0x%x", off);
    }
}

/*
 * Instruction class specific routines.
 */

public omove(inst, s)
long inst;
String s;
{
    register int c;
    int size;

    c = s[0];
    if (printing) {
        printf("\tmov%c\t", c);
    }
    size = ((c == 'b') ? 1 : (c == 'w') ? 2 : 4);
    printea((inst>>3)&07, inst&07, size);
    if (printing) {
        printf(",");
    }
    printea((inst>>6)&07, (inst>>9)&07, size);
}

/*
 * Two types: bsr (4 bytes) and bsrs (2 bytes)
 */

public obranch(inst, dummy)
long inst;
{
    long disp;
    String s;
    short w;
    Address startingaddr;       /* address of branch instruction */
    int branchtype;             /* type of branch (0 = unconditional) */
    Address dest;
    Address retaddr;            /* for bsr instruction */

    startingaddr = instaddr - 2;
    disp = inst&0377;
    s = "s ";
    if (disp == 0) {
        retaddr = startingaddr + 4;
    } else {
        retaddr = startingaddr + 2;
    }
    if (disp > 127) {
        disp |= ~0377;
    } else if (disp == 0){
        s = " ";
        instread(w);
        disp = w;
    }
    branchtype = (int)((inst>>8)&017);
    dest = startingaddr + 2 + disp;
    if (printing) {
        printf("\tb%s%s\t", bname[branchtype], s);
        psymoff(dest);
    }
    if (following) {
        /*
         * If we're to follow the dynamic flow of instructions,
         * we must see where the branch leads.  A branchtype of 0
         * indicates an unconditional branch which we simply take
         * as the new instruction address.  For a conditional branch,
         * we continue execution up to the current address, single step,
         * and keep going.
         */
        if (branchtype == 0) {
            instaddr = dest;
        } else if (branchtype == 01) {          /* bsr */
            if (followcalls) {
                steppast(startingaddr);
                curfunc = whatblock(pc, true);
                if (not isbperr()) {
                    printstatus();
                    /* NOTREACHED */
                }
                bpact();
                if (nosource(curfunc) and canskip(curfunc) and
                  nlhdr.nlines != 0) {
                    stepto(retaddr);
                    instaddr = pc;
                    bpact();
                } else {
                    callnews(/* iscall = */ true);
                }
            }
        } else {
            steppast(startingaddr);
        }
    }
}

public odbcc(inst, form)
long inst;
String form;
{
    long disp;
    short w;

    instread(w);
    if (printing) {
        printf(form, dbname[(int)((inst>>8)&017)], inst&07);
        psymoff(w + sizeof(w));
    }
}

public oscc(inst, dummy)
long inst;
long dummy;
{
    if (printing) {
        printf("\ts%s\t", cname[(int)((inst>>8)&017)]);
    }
    printea((inst>>3)&07, inst&07, 1);
}

public biti(inst, dummy)
long inst;
long dummy;
{
    short w;

    if (printing) {
        printf("\t%s\t", bit[(int)((inst>>6)&03)]);
    }
    if (inst&0x0100) {
        if (printing) {
            printf("d%D,", inst>>9);
        }
    } else {
        instread(w);
        if (printing) {
            printf(IMDF, w);
            printf(",");
        }
    }
    printEA(inst);
}

public opmode(inst, opcode)
long inst;
long opcode;
{
    register int opmode;
    register int reg;
    int size;

    opmode = (int)((inst>>6) & 07);
    reg = (int)((inst>>9) & 07);
    if (opmode == 0 or opmode == 4) {
        size = 1;
    } else if (opmode == 1 or opmode == 3 or opmode == 5) {
        size = 2;
    } else {
        size = 4;
    }
    if (printing) {
        printf("\t%s%c\t", opcode, suffix(size));
    }
    if (opmode >= 4 and opmode <= 6) {
        if (printing) {
            printf("d%d,", reg);
        }
        printea((inst>>3)&07, inst&07, size);
    } else {
        printea((inst>>3)&07, inst&07, size);
        if (printing) {
            printf(",%c%d",(opmode<=2) ? 'd' : 'a', reg);
        }
    }
}

public shroi(inst, ds)
long inst;
String ds;
{
    int rx, ry;
    String opcode;

    if ((inst & 0xC0) == 0xC0) {
        opcode = shro[(int)((inst>>9)&03)];
        if (printing) {
            printf("\t%s%s\t", opcode, ds);
        }
        printEA(inst);
    } else {
        if (printing) {
            opcode = shro[(int)((inst>>3)&03)];
            printf("\t%s%s%c\t", opcode, ds, suffix(mapsize(inst)));
            rx = (int)((inst>>9)&07); ry = (int)(inst&07);
            if ((inst>>5)&01) {
                printf("d%d,d%d", rx, ry);
            } else {
                printf(IMDF, (rx ? rx : 8));
                printf(",d%d", ry);
            }
        }
    }
}

public oimmed(inst, opcode)
long inst;
register String opcode;
{
    register int size;
    long const;
    short w;

    size = mapsize(inst);
    if (size > 0) {
        if (size == 4) {
            instread(const);
        } else {
            instread(w);
            const = w;
        }
        if (printing) {
            printf("\t%s%c\t", opcode, suffix(size));
            printf(IMDF, const);
            printf(",");
        }
        printEA(inst, size);
    } else {
        if (printing) {
            printf("\tbadop");
        }
    }
}

public oreg(inst, opcode)
long inst;
register String opcode;
{
    if (printing) {
        printf(opcode, (inst & 07));
    }
}

public extend(inst, opcode)
long inst;
String opcode;
{
    register int size;
    int ry, rx;
    char c;

    if (printing) {
        size = mapsize(inst);
        ry = (inst&07);
        rx = ((inst>>9)&07);
        c = ((inst & 0x1000) ? suffix(size) : ' ');
        printf("\t%s%c\t", opcode, c);
        if (opcode[0] == 'e') {
            if (inst & 0x0080) {
                printf("d%D,a%D", rx, ry);
            } else if (inst & 0x0008) {
                printf("a%D,a%D", rx, ry);
            } else {
                printf("d%D,d%D", rx, ry);
            }
        } else if ((inst & 0xF000) == 0xB000) {
            printf("a%D@+,a%D@+", ry, rx);
        } else if (inst & 0x8) {
            printf("a%D@-,a%D@-", ry, rx);
        } else {
            printf("d%D,d%D", ry, rx);
        }
    }
}

public olink(inst, dummy)
long inst;
long dummy;
{
    short w;

    instread(w);
    if (printing) {
        printf("\tlink\ta%D,", inst&07);
        printf(IMDF, w);
    }
}

public otrap(inst, dummy)
long inst;
{
    if (printing) {
        printf("\ttrap\t");
        printf(IMDF, inst&017);
    }
}

public oneop(inst, opcode)
long inst;
register String opcode;
{
    if (printing) {
        printf("\t%s",opcode);
    }
    printEA(inst);
}

public jsrop(inst, opcode)
long inst;
register String opcode;
{
    Address startingaddr;       /* beginning of jsr instruction */
    Address retaddr; /* can't call return_addr (frame not set up yet) */

    startingaddr = instaddr - 2;
    switch ((inst >> 3) & 07) {
        case 2:
            retaddr = instaddr;         /* two byte instruction */
            break;
        case 5:
        case 6:
            retaddr = instaddr + 2;     /* four byte instruction */
            break;
        case 7:
        default:
            switch (inst & 07) {
                case 0:
                case 2:
                case 3:
                    retaddr = instaddr + 2;
                    break;
                case 1:
                default:
                    retaddr = instaddr + 4;     /* six byte instruction */
                    break;
            }
            break;
    }
    if (printing) {
        printf("\t%s",opcode);
    }
    printEA(inst);
    if (following and followcalls) {
        steppast(startingaddr);
        curfunc = whatblock(pc, true);
        if (not isbperr()) {
            printstatus();
            /* NOTREACHED */
        }
        bpact();
        if (nosource(curfunc) and canskip(curfunc) and nlhdr.nlines != 0) {
            stepto(retaddr);
            instaddr = pc;
            bpact();
        } else {
            callnews(/* iscall = */ true);
        }
    }
}

public jmpop(inst, opcode)
long inst;
register String opcode;
{
    Address startingaddr;       /* beginning of jump instruction */

    startingaddr = instaddr - 2;
    if (printing) {
        printf("\t%s",opcode);
    }
    printEA(inst);
    if (following) {
        steppast(startingaddr);
    }
}

public pregmask(mask)
register int mask;
{
    register int i;
    register int flag = 0;

    if (printing) {
        printf("#<");
        for (i=0; i<16; i++) {
            if (mask&1) {
                if (flag) {
                    printf(",");
                } else {
                    ++flag;
                }
                printf("%c%d",(i<8) ? 'd' : 'a', i&07);
            }
            mask >>= 1;
        }
        printf(">");
    }
}

public omovem(inst, dummy)
long inst;
long dummy;
{
    register int i, list, mask;
    register int reglist;
    short w;

    i = 0;
    list = 0;
    mask = 0100000;
    instread(w);
    reglist = w;
    if ((inst & 070) == 040) {  /* predecrement */
        for (i = 15; i > 0; i -= 2) {
            list |= ((mask & reglist) >> i);
            mask >>= 1;
        }
        for (i = 1; i < 16; i += 2) {
            list |= ((mask & reglist) << i);
            mask >>= 1;
        }
        reglist = list;
    }
    if (printing) {
        printf("\tmovem%c\t",(inst&100)?'l':'w');
    }
    if (inst&02000) {
        printEA(inst);
        if (printing) {
            printf(",");
        }
        pregmask(reglist);
    } else {
        pregmask(reglist);
        if (printing) {
            printf(",");
        }
        printEA(inst);
    }
}

public ochk(inst, opcode)
long inst;
register String opcode;
{
    if (printing) {
        printf("\t%s\t", opcode);
    }
    printEA(inst, sizeof(Byte));
    if (printing) {
        printf(",%c%D", (opcode[0] == 'l') ? 'a' : 'd', (inst>>9)&07);
    }
}

public soneop(inst, opcode)
long inst;
register String opcode;
{
    register int size;

    size = mapsize(inst);
    if (size > 0) {
        if (printing) {
            printf("\t%s%c\t", opcode, suffix(size));
        }
        printEA(inst);
    } else {
        if (printing) {
            printf("\tbadop");
        }
    }
}

public oquick(inst, opcode)
long inst;
register String opcode;
{
    register int size;
    register int data;

    size = mapsize(inst);
    data = (int)((inst>>9) & 07);
    if (data == 0) {
        data = 8;
    }
    if (size > 0) {
        if (printing) {
            printf("\t%s%c\t", opcode, suffix(size));
            printf(IMDF, data);
            printf(",");
        }
        printEA(inst);
    } else {
        if (printing) {
            printf("\tbadop");
        }
    }
}

public omoveq(inst, dummy)
long inst;
long dummy;
{
    register int data;

    if (printing) {
        data = (int)(inst & 0377);
        if (data > 127) {
            data |= ~0377;
        }
        printf("\tmoveq\t");
        printf(IMDF, data);
        printf(",d%D", (inst>>9)&07);
    }
}

public oprint(inst, opcode)
long inst;
register String opcode;
{
    if (printing) {
        printf("\t%s",opcode);
    }
}

public ostop(inst, opcode)
long inst;
register String opcode;
{
    short w;

    instread(w);
    if (printing) {
        printf(opcode, w);
    }
}

public orts(inst, opcode)
long inst;
register String opcode;
{
    Address addr;

    if (following) {
        callnews(/* iscall = */ false);
        if (inst_tracing) {
            addr = currtnaddr();
        } else {
            addr = return_addr();
            if (addr == 0) {
                stepto(instaddr - 2);
                addr = currtnaddr();
            }
        }
        stepto(addr);
        instaddr = pc;
    }
    if (printing) {
        printf("\t%s",opcode);
    }
}

/*
 * Not used by C compiler; does an rts but before doing so, pops
 * arg bytes from the stack.
 */

public ortspop(inst, opcode)
long inst;
register String opcode;
{
    Address addr;
    short w;

    instread(w);
    if (following) {
        callnews(/* iscall = */ false);
        if (inst_tracing) {
            addr = currtnaddr();
        } else {
            addr = return_addr();
        }
        stepto(addr);
        instaddr = pc;
    }
    if (printing) {
        printf(opcode, w);
    }
}

public omovs(inst, opcode)
long inst;
String opcode;
{
    register int size;
    register unsigned int controlword;
    short w;

    size = mapsize(inst);
    instread(w);
    controlword = w >> 11;
    if (printing) {
        printf("\t%s%c\t", opcode, suffix(size));
    }
    if (controlword & 1){
        controlword >>= 1;
        if (printing) {
            printf((controlword&0x8) ? "a%D," : "d%D,", controlword&7 );
        }
        printEA(inst&0xff, size);
    } else {
        controlword >>= 1;
        printEA(inst&0xff, size);
        if (printing) {
            printf((controlword&0x8) ? ",a%D" : ",d%D", controlword&7);
        }
    }
}

public omovc(inst, opcode)
long inst;
String opcode;
{
    register unsigned int controlword;
    String creg;
    short w;

    instread(w);
    if (printing) {
        controlword = w;
        switch (controlword & 0xfff) {
            case 0:
                creg = "sfc";
                break;

            case 1:
                creg = "dfc";
                break;

            case 0x800:
                creg = "usp";
                break;

            case 0x801:
                creg = "vbr";
                break;

            default:
                creg = "???";
                break;
        }
        controlword >>= 12;
        if (inst & 1){
            printf((controlword&0x8) ? "%sa%D,%s" : "%sd%D,%s",
                opcode, controlword&7, creg );
        } else {
            printf((controlword&0x8) ? "%s%s,a%D" : "%s%s,d%D",
                opcode, creg, controlword&7 );
        }
    }
}

/*
 * Compute the next address that will be executed from the given one.
 * If "isnext" is true then consider a procedure call as straight line code.
 *
 * Unconditional branches we just follow, for conditional branches
 * we continue execution to the current location and then single step
 * the machine.
 */

public Address nextaddr(startaddr, isnext)
Address startaddr;
Boolean isnext;
{
    Optab *o;
    short inst;

    instaddr = usignal(process);
    if (instaddr == 0 or instaddr == 1) {
        following = true;
        followcalls = (Boolean) (not isnext);
        printing = false;
        iread(&inst, startaddr, sizeof(inst));
        instaddr = startaddr + sizeof(inst);
        o = decode(inst, startaddr);
        if (o->mask == 0) {
            fprintf(stderr,
                "[internal error: undecodable op at 0x%x]\n", startaddr);
            fflush(stderr);
        } else {
            (*o->opfun)(inst, o->farg);
        }
        following = false;
    }
    return instaddr;
}

/*
 * Step to the given address and then execute one instruction past it.
 * Set instaddr to the new instruction address.
 */

private steppast(addr)
Address addr;
{
    stepto(addr);
    pstep(process, DEFSIG);
    pc = reg(PROGCTR);
    instaddr = pc;
}

/*
 * Enter a procedure by creating and executing a call instruction.
 */

#define CALLSIZE 6      /* size of call instruction */

public beginproc(p)
Symbol p;
{
    char save[CALLSIZE];
    struct {
        short op;
        char addr[sizeof(long)];        /* unaligned long */
    } call;
    long dest;

    pc = CODESTART + 6;
    iread(save, pc, sizeof(save));
    call.op = 0x4eb9;                   /* jsr */
    dest = codeloc(p) - FUNCOFFSET;
    mov(&dest, call.addr, sizeof(call.addr));
    iwrite(&call, pc, sizeof(call));
    setreg(PROGCTR, pc);
    pstep(process, DEFSIG);
    iwrite(save, pc, sizeof(save));
    pc = reg(PROGCTR);
    if (not isbperr()) {
        printstatus();
    }
    /*
     * Execute link instruction so the return addr is visible.
     */
    pstep(process, DEFSIG);
    pc = reg(PROGCTR);
    if (not isbperr()) {
        printstatus();
    }
}

/*
 * Special variables for debugging the kernel.
 */

public integer masterpcbb;
public integer slr;
public struct pte *sbr;
private struct pcb pcb;

public getpcb ()
{
    integer i;

    fseek(corefile, masterpcbb & ~0x80000000, 0);
    get(corefile, pcb);
    pcb.pcb_p0lr &= ~AST_CLR;
    printf("p0br %lx p0lr %lx p1br %lx p1lr %lx\n",
        pcb.pcb_p0br, pcb.pcb_p0lr, pcb.pcb_p1br, pcb.pcb_p1lr
    );
#   ifdef sun
    for (i = 0; i < 14; i++) {
        setreg(i, pcb.pcb_regs.val[i]);
    }
#   else /* IRIS */
    for (i = 0; i < 14; i++) {
        setreg(i, pcb.pcb_regs[i]);
    }
#   endif
}

public copyregs (savreg, reg)
Word savreg[], reg[];
{
    reg[0] = savreg[R0];
    reg[1] = savreg[R1];
    reg[2] = savreg[R2];
    reg[3] = savreg[R3];
    reg[4] = savreg[R4];
    reg[5] = savreg[R5];
    reg[6] = savreg[R6];
    reg[7] = savreg[R7];
    reg[8] = savreg[AR0];
    reg[9] = savreg[AR1];
    reg[10] = savreg[AR2];
    reg[11] = savreg[AR3];
    reg[12] = savreg[AR4];
    reg[13] = savreg[AR5];
    reg[14] = savreg[AR6];
    reg[15] = savreg[AR7];
    reg[PROGCTR] = savreg[PC];
}

/*
 * Map a virtual address to a physical address.
 * XXX THIS CAN'T BE RIGHT... XXX
 */

public Address vmap (addr)
Address addr;
{
    Address r;
    integer v, n;
    struct pte pte;

    r = addr & ~0xc0000000;
    v = btop(r);
    switch (addr&0xc0000000) {
        case 0xc0000000:
        case 0x80000000:
            /*
             * In system space, so get system pte.
             * If it is valid or reclaimable then the physical address
             * is the combination of its page number and the page offset
             * of the original address.
             */
            if (v >= slr) {
                error("address %x out of segment", addr);
            }
            r = ((long) (sbr + v)) & ~0x80000000;
            goto simple;

        case 0x40000000:
            /*
             * In p1 space, must not be in shadow region.
             */
            if (v < pcb.pcb_p1lr) {
                error("address %x out of segment", addr);
            }
            r = (Address) (pcb.pcb_p1br + v);
            break;

        case 0x00000000:
            /*
             * In p0 space, must not be off end of region.
             */
            if (v >= pcb.pcb_p0lr) {
                error("address %x out of segment", addr);
            }
            r = (Address) (pcb.pcb_p0br + v);
            break;

        default:
            /* do nothing */
            break;
    }
    /*
     * For p0/p1 address, user-level page table should be in
     * kernel virtual memory.  Do second-level indirect by recursing.
     */
    if ((r & 0x80000000) == 0) {
        error("bad p0br or p1br in pcb");
    }
    r = vmap(r);
simple:
    /*
     * "r" is now the address of the pte of the page
     * we are interested in; get the pte and paste up the physical address.
     */
    fseek(corefile, r, 0);
    n = fread(&pte, sizeof(pte), 1, corefile);
    if (n != 1) {
        error("page table botch (fread at %x returns %d)", r, n);
    }
    if (pte.pg_v == 0 and (pte.pg_fod != 0 or pte.pg_pfnum == 0)) {
        error("page no valid or reclamable");
    }
    return (addr&PGOFSET) + ((Address) ptob(pte.pg_pfnum));
}

/*
 * Extract a bit field from an integer.
 */

public integer extractField (s)
Symbol s;
{
    integer nbytes, nbits, n, r, off, len;

    off = s->symvalue.field.offset;
    len = s->symvalue.field.length;
    nbytes = size(s);
    n = 0;
    if (nbytes > sizeof(n)) {
        printf("[bad size in extractField -- word assumed]\n");
        nbytes = sizeof(n);
    }
    popn(nbytes, ((char *) &n) + (sizeof(Word) - nbytes));
    nbits = nbytes * BITSPERBYTE;
    r = n >> (nbits - ((off mod nbits) + len));
    r &= ((1 << len) - 1);
    return r;
}

/*
 * Change the length of a value in memory according to a given difference
 * in the lengths of its new and old types.
 */

public loophole (oldlen, newlen)
integer oldlen, newlen;
{
    integer i, n;
    Stack *oldsp;

    n = newlen - oldlen;
    oldsp = sp - oldlen;
    if (n > 0) {
        for (i = oldlen - 1; i >= 0; i--) {
            oldsp[n + i] = oldsp[i];
        }
        for (i = 0; i < n; i++) {
            oldsp[i] = '\0';
        }
    } else {
        for (i = 0; i < newlen; i++) {
            oldsp[i] = oldsp[i - n];
        }
    }
    sp += n;
}