vax.c

早期freebsd实现

				printf("%g", *(float *)&argval);
			    }
			    addr += 4;
			    break;

			case TYPD:
			    /* XXX this bags the low order bits */
			    iread(&argval, addr, sizeof(argval));
			    if ((argval & 0xffff007f) == 0x8000) {
				printf("[reserved operand]");
			    } else {
				printf("%g", *(float *)&argval);
			    }
			    addr += 8;
			    break;

			case TYPG:
			case TYPQ:
			    iread(&argval, addr+4, sizeof(argval));
			    printf("%08x", argval);
			    iread(&argval, addr, sizeof(argval));
			    printf("%08x", argval);
			    addr += 8;
			    break;

			case TYPH:
			case TYPO:
			    iread(&argval, addr+12, sizeof(argval));
			    printf("%08x", argval);
			    iread(&argval, addr+8, sizeof(argval));
			    printf("%08x", argval);
			    iread(&argval, addr+4, sizeof(argval));
			    printf("%08x", argval);
			    iread(&argval, addr, sizeof(argval));
			    printf("%08x", argval);
			    addr += 16;
			    break;
		    }
		}
		break;

	    case AUTOINCDEF:
		if (reg == regname[PROGCTR]) {
		    printf("*$");
		    argval = printdisp(addr, 4, reg, amode);
		    addr += 4;
		} else {
		    printf("*(%s)+", reg);
		}
		break;

	    case BYTEDISP:
		argval = printdisp(addr, 1, reg, amode);
		addr += 1;
		break;

	    case BYTEDISPDEF:
		printf("*");
		argval = printdisp(addr, 1, reg, amode);
		addr += 1;
		break;

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

	    case WORDDISPDEF:
		printf("*");
		argval = printdisp(addr, 2, reg, amode);
		addr += 2;
		break;

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

	    case LONGDISPDEF:
		printf("*");
		argval = printdisp(addr, 4, reg, amode);
		addr += 4;
		break;
	}
    }
    if (ins == O_CASEB || ins == O_CASEW || ins == O_CASEL) {
	for (argno = 0; argno <= argval; argno++) {
	    iread(&offset, addr, sizeof(offset));
	    printf("\n\t\t%d", offset);
	    addr += 2;
	}
    }
    printf("\n");
    return addr;
}

/*
 * Print the displacement of an instruction that uses displacement
 * addressing.
 */

private int printdisp(addr, nbytes, reg, mode)
Address addr;
int nbytes;
char *reg;
int mode;
{
    char byte;
    short hword;
    int argval;
    Symbol f;

    switch (nbytes) {
	case 1:
	    iread(&byte, addr, sizeof(byte));
	    argval = byte;
	    break;

	case 2:
	    iread(&hword, addr, sizeof(hword));
	    argval = hword;
	    break;

	case 4:
	    iread(&argval, addr, sizeof(argval));
	    break;
    }
    if (reg == regname[PROGCTR] && mode >= BYTEDISP) {
	argval += addr + nbytes;
    }
    if (reg == regname[PROGCTR]) {
	f = whatblock((Address) argval + 2);
	if (codeloc(f) == argval + 2) {
	    printf("%s", symname(f));
	} else {
	    printf("%x", argval);
	}
    } else {
	if (varIsSet("$hexoffsets")) {
	    if (argval < 0) {
		printf("-%x(%s)", -(argval), reg);
	    } else {
		printf("%x(%s)", argval, reg);
	    }
	} else {
	    printf("%d(%s)", argval, reg);
	}
    }
    return argval;
}

/*
 * 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.
 *
 * We must unfortunately do much of the same work that is necessary
 * to print instructions.  In addition we have to deal with branches.
 * Unconditional branches we just follow, for conditional branches
 * we continue execution to the current location and then single step
 * the machine.  We assume that the last argument in an instruction
 * that branches is the branch address (or relative offset).
 */

private Address findnextaddr();

public Address nextaddr(startaddr, isnext)
Address startaddr;
boolean isnext;
{
    Address addr;

    addr = usignal(process);
    if (addr == 0 or addr == 1) {
	addr = findnextaddr(startaddr, isnext);
    }
    return addr;
}

/*
 * Determine if it's ok to skip function f entered by instruction ins.
 * If so, we're going to compute the return address and step to it.
 * Therefore we cannot skip over a function entered by a jsb or bsb,
 * since the return address is not easily computed for them.
 */

private boolean skipfunc (ins, f)
VaxOpcode ins;
Symbol f;
{
    boolean b;

    b = (boolean) (
	ins != O_JSB and ins != O_BSBB and ins != O_BSBW and
	not inst_tracing and nlhdr.nlines != 0 and
	nosource(curfunc) and canskip(curfunc)
    );
    return b;
}

private Address findnextaddr(startaddr, isnext)
Address startaddr;
Boolean isnext;
{
    register Address addr;
    register Optab *op;
    VaxOpcode ins, ins2;
    unsigned char mode;
    int argtype, amode, argno, argval;
    String r;
    Boolean indexf;
    enum { KNOWN, SEQUENTIAL, BRANCH } addrstatus;

    argval = 0;
    indexf = false;
    addr = startaddr;
    iread(&ins, addr, sizeof(ins));
    switch (ins) {
	/*
	 * It used to be that unconditional jumps and branches were handled
	 * by taking their destination address as the next address.  While
	 * saving the cost of starting up the process, this approach
	 * doesn't work when jumping indirect (since the value in the
	 * register might not yet have been set).
	 *
	 * So unconditional jumps and branches are now handled the same way
	 * as conditional jumps and branches.
	 *
	case O_BRB:
	case O_BRW:
	    addrstatus = BRANCH;
	    break;
	 *
	 */
	    
	case O_BSBB:
	case O_BSBW:
	case O_JSB:
	case O_CALLG:
	case O_CALLS:
	    addrstatus = KNOWN;
	    stepto(addr);
	    pstep(process, DEFSIG);
	    addr = reg(PROGCTR);
	    pc = addr;
	    setcurfunc(whatblock(pc));
	    if (not isbperr()) {
		printstatus();
		/* NOTREACHED */
	    }
	    bpact();
	    if (isnext or skipfunc(ins, curfunc)) {
		addrstatus = KNOWN;
		addr = return_addr();
		stepto(addr);
		bpact();
	    } else {
		callnews(/* iscall = */ true);
	    }
	    break;

	case O_RSB:
	case O_RET:
	    addrstatus = KNOWN;
	    stepto(addr);
	    callnews(/* iscall = */ false);
	    pstep(process, DEFSIG);
	    addr = reg(PROGCTR);
	    pc = addr;
	    if (not isbperr()) {
		printstatus();
	    }
	    bpact();
	    break;

	case O_BRB: case O_BRW:
	case O_JMP: /* because it may be jmp (r1) */
	case O_BNEQ: case O_BEQL: case O_BGTR:
	case O_BLEQ: case O_BGEQ: case O_BLSS:
	case O_BGTRU: case O_BLEQU: case O_BVC:
	case O_BVS: case O_BCC: case O_BCS:
	case O_CASEB: case O_CASEW: case O_CASEL:
	case O_BBS: case O_BBC: case O_BBSS: case O_BBCS:
	case O_BBSC: case O_BBCC: case O_BBSSI:
	case O_BBCCI: case O_BLBS: case O_BLBC:
	case O_ACBL: case O_AOBLSS: case O_AOBLEQ:
	case O_SOBGEQ: case O_SOBGTR:
	case O_ESCF: /* bugchecks */
	branches:
	    addrstatus = KNOWN;
	    stepto(addr);
	    pstep(process, DEFSIG);
	    addr = reg(PROGCTR);
	    pc = addr;
	    if (not isbperr()) {
		printstatus();
	    }
	    break;

	case O_ESCD:
	    iread(&ins2, addr+1, sizeof(ins2));
	    if (ins2 == O_ACBF || ins2 == O_ACBD)
		/* actually ACBG and ACBH */
		goto branches;
	    /* fall through */

	default:
	    addrstatus = SEQUENTIAL;
	    break;
    }
    if (addrstatus != KNOWN) {
	addr += 1;
	if (ins == O_ESCD) {
	    ins = ins2;
	    addr += 1;
	    op = esctab[ins];
	    if (op == nil) {
		printf("[bad extended opcode %#x in findnextaddr]\n", ins);
		return addr;
	    }
	} else {
	    op = ioptab[ins];
	    if (op == nil) {
		printf("[bad opcode %#x in findnextaddr]\n", ins);
		return addr;
	    }
	}
	for (argno = 0; argno < op->numargs; argno++) {
	    if (indexf == true) {
		indexf = false;
	    }
	    argtype = op->argtype[argno];
	    if (is_branch_disp(argtype)) {
		mode = 0xAF + (typelen(argtype) << 5);
	    } else {
		iread(&mode, addr, sizeof(mode));
		addr += 1;
	    }
	    r = regname[regnm(mode)];
	    amode = addrmode(mode);
	    switch (amode) {
		case LITSHORT:
		case LITUPTO31:
		case LITUPTO47:
		case LITUPTO63:
		    argval = mode;
		    break;

		case INDEX:
		    indexf = true;
		    --argno;
		    break;

		case REG:
		case REGDEF:
		case AUTODEC:
		    break;

		case AUTOINC:
		    if (r == regname[PROGCTR]) {
			switch (typelen(argtype)) {
			    case TYPB:
				argval = getdisp(addr, 1, r, amode);
				addr += 1;
				break;

			    case TYPW:
				argval = getdisp(addr, 2, r, amode);
				addr += 2;
				break;

			    case TYPL:
				argval = getdisp(addr, 4, r, amode);
				addr += 4;
				break;

			    case TYPF:
				iread(&argval, addr, sizeof(argval));
				addr += 4;
				break;

			    case TYPQ:
			    case TYPD:
			    case TYPG:
				iread(&argval, addr+4, sizeof(argval));
				addr += 8;
				break;

			    case TYPO:
			    case TYPH:
				iread(&argval, addr+12, sizeof(argval));
				addr += 16;
				break;
			}
		    }
		    break;

		case AUTOINCDEF:
		    if (r == regname[PROGCTR]) {
			argval = getdisp(addr, 4, r, amode);
			addr += 4;
		    }
		    break;

		case BYTEDISP:
		case BYTEDISPDEF:
		    argval = getdisp(addr, 1, r, amode);
		    addr += 1;
		    break;

		case WORDDISP:
		case WORDDISPDEF:
		    argval = getdisp(addr, 2, r, amode);
		    addr += 2;
		    break;

		case LONGDISP:
		case LONGDISPDEF:
		    argval = getdisp(addr, 4, r, amode);
		    addr += 4;
		    break;
	    }
	}
	if (ins == O_CALLS or ins == O_CALLG) {
	    argval += 2;
	}
	if (addrstatus == BRANCH) {
	    addr = argval;
	}
    }
    return addr;
}

/*
 * Get the displacement of an instruction that uses displacement addressing.
 */

private int getdisp(addr, nbytes, reg, mode)
Address addr;
int nbytes;
String reg;
int mode;
{
    char byte;
    short hword;
    int argval;

    switch (nbytes) {
	case 1:
	    iread(&byte, addr, sizeof(byte));
	    argval = byte;
	    break;

	case 2:
	    iread(&hword, addr, sizeof(hword));
	    argval = hword;
	    break;

	case 4:
	    iread(&argval, addr, sizeof(argval));
	    break;
    }
    if (reg == regname[PROGCTR] && mode >= BYTEDISP) {
	argval += addr + nbytes;
    }
    return argval;
}

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

#define CALLSIZE 7	/* size of call instruction */

public beginproc(p, argc)
Symbol p;
Integer argc;
{
    char save[CALLSIZE];
    struct {
	VaxOpcode op;
	unsigned char numargs;
	unsigned char mode;
	char addr[sizeof(long)];	/* unaligned long */
    } call;
    long dest;

    pc = 2;
    iread(save, pc, sizeof(save));
    call.op = O_CALLS;
    call.numargs = argc;
    call.mode = 0xef;
    dest = codeloc(p) - 2 - (pc + 7);
    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();
    }
}

/*
 * 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
    );
    setreg(0, pcb.pcb_r0);
    setreg(1, pcb.pcb_r1);
    setreg(2, pcb.pcb_r2);
    setreg(3, pcb.pcb_r3);
    setreg(4, pcb.pcb_r4);
    setreg(5, pcb.pcb_r5);
    setreg(6, pcb.pcb_r6);
    setreg(7, pcb.pcb_r7);
    setreg(8, pcb.pcb_r8);
    setreg(9, pcb.pcb_r9);
    setreg(10, pcb.pcb_r10);
    setreg(11, pcb.pcb_r11);
    setreg(ARGP, pcb.pcb_ap);
    setreg(FRP, pcb.pcb_fp);
    setreg(STKP, pcb.pcb_ksp);
    setreg(PROGCTR, pcb.pcb_pc);
}

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[R8];
    reg[9] = savreg[R9];
    reg[10] = savreg[R10];
    reg[11] = savreg[R11];
    reg[ARGP] = savreg[AP];
    reg[FRP] = savreg[FP];
    reg[STKP] = savreg[SP];
    reg[PROGCTR] = savreg[PC];
}

/*
 * Map a virtual address to a physical address.
 */

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 n, nbytes, r;

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

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