vax.c

早期freebsd实现

/*
 * Copyright (c) 1983 The Regents of the University of California.
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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 BY THE REGENTS 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 REGENTS 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.
 */

#ifndef lint
static char sccsid[] = "@(#)vax.c	5.8 (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;

#define NREG 16

#define ARGP 12
#define FRP 13
#define STKP 14
#define PROGCTR 15

#define CODESTART 0
#define FUNCOFFSET 2

#define nargspassed(frame) argn(0, frame)

#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)))

#include "source.h"
#include "symbols.h"
#include <signal.h>
#include <sys/param.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[] ={
    R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, AP, FP, SP, PC
};

private Address printop();

private Optab *ioptab[256];	/* index by opcode to optab */
private Optab *esctab[256];	/* for extended opcodes */

/*
 * Initialize the opcode lookup table.
 */
public optab_init()
{
    register Optab *p;

    for (p = optab; p->iname; p++) {
	if (p->format == O_ESCD) {
	    esctab[p->val] = p;
	} else if (p->format != O_ESCD && p->format != O_ESCE) {
	    ioptab[p->val] = p;
	}
    }
}

/*
 * 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 char Bpinst;

#define BP_OP       O_BPT       /* breakpoint trap */

#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);
}

/*
 * VAX instruction decoder, derived from adb.
 */

private Address printop(addr)
Address addr;
{
    register Optab *op;
    VaxOpcode ins;
    unsigned char mode;
    int argtype, amode, argno, argval;
    String reg;
    Boolean indexf;
    short offset;

    argval = 0;
    indexf = false;
    printf("%08x  ", addr);
    iread(&ins, addr, sizeof(ins));
    addr += 1;
    if (ins == O_ESCF) {
	iread(&ins, addr, sizeof(ins));
	addr += 1;
	op = ioptab[ins];
    } else if (ins == O_ESCD) {
	iread(&ins, addr, sizeof(ins));
	addr += 1;
	op = esctab[ins];
    } else {
	op = ioptab[ins];
    }
    if (op == nil) {
	printf("[unrecognized opcode %#0x]\n", ins);
	return addr;
    }
    printf("%s", op->iname);
    for (argno = 0; argno < op->numargs; argno++) {
	if (indexf == true) {
	    indexf = false;
	} else if (argno == 0) {
	    printf("\t");
	} else {
	    printf(",");
	}
	argtype = op->argtype[argno];
	if (is_branch_disp(argtype)) {
	    mode = 0xAF + (typelen(argtype) << 5);
	} else {
	    iread(&mode, addr, sizeof(mode));
	    addr += 1;
	}
	reg = regname[regnm(mode)];
	amode = addrmode(mode);
	switch (amode) {
	    case LITSHORT:
	    case LITUPTO31:
	    case LITUPTO47:
	    case LITUPTO63:
		if (typelen(argtype) == TYPF || typelen(argtype) == TYPD ||
		    typelen(argtype) == TYPG || typelen(argtype) == TYPH)
		    printf("$%s", fltimm[mode]);
		else
		    printf("$%x", mode);
		argval = mode;
		break;

	    case INDEX:
		printf("[%s]", reg);
		indexf = true;
		argno--;
		break;

	    case REG:
		printf("%s", reg);
		break;

	    case REGDEF:
		printf("(%s)", reg);
		break;

	    case AUTODEC:
		printf("-(%s)", reg);
		break;

	    case AUTOINC:
		if (reg != regname[PROGCTR]) {
		    printf("(%s)+", reg);
		} else {
		    printf("$");
		    switch (typelen(argtype)) {
			case TYPB:
			    argval = printdisp(addr, 1, reg, amode);
			    addr += 1;
			    break;

			case TYPW:
			    argval = printdisp(addr, 2, reg, amode);
			    addr += 2;
			    break;

			case TYPL:
			    argval = printdisp(addr, 4, reg, amode);
			    addr += 4;
			    break;

			case TYPF:
			    iread(&argval, addr, sizeof(argval));
			    if ((argval & 0xffff007f) == 0x8000) {
				printf("[reserved operand]");
			    } else {