getput.c

计算机系统结构的讲义,浓缩了一本一千多页的书.真的是好东西.

/* 
 * getput.c --
 *
 * This file implements commands to query or change the state
 * of the DLX machine being simulated.
 *
 *  This file is part of DISC.  It was modified by Yinong Zhang 
 *  ([e-mail]) from the file "getput.c" in the distribution
 *  of "dlxsim" available at:
 *     ftp://max.stanford.edu/pub/hennessy-patterson.software/dlx.tar.Z
 *
 *  The original source code is copyright as follows:
 *
 * Copyright 1989 Regents of the University of California
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies.  The University of California
 * makes no representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 *
 */

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <tcl.h>
#include "dlx.h"
#include "sym.h"



/*
 * Forward declarations for procedures declared later in this file:
 */
static int	GetAddress(DLX *, char *, unsigned int *, int *);
static char *	GetString(DLX *, unsigned int, int *);


/*
 *----------------------------------------------------------------------
 *
 * Gp_GetCmd --
 *
 *	This procedure is invoked to process the "get" Tcl command.
 *	See the user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

int
Gp_GetCmd(clientData, interp, argc, argv)
    ClientData clientData;
    Tcl_Interp *interp;			/* Current interpreter. */
    int argc;				/* Number of arguments. */
    char **argv;			/* Argument strings. */
{
    DLX *machPtr = (DLX *) clientData;
    unsigned int address;
    int isReg, result, totalSpace, spaceNeeded;
    enum {BINARY, HEX, DECIMAL, CHAR, STRING, INS} format = HEX;
    int length = 4;			/* # bytes in each value to print. */
    int count = 1;			/* # of values to print. */
    int addrIsValue = 0;		/* Print address instead of value. */
    char *p;				/* Points to NULL char. at end of
					 * current result. */
    int dynamic = 0;
    char *locString, *valueString;
    char locBuf[100], valueBuf[100];

    if ((argc != 2) && (argc != 3)) {
	sprintf(interp->result,
		"wrong # args:  should be \"%.50s location [flags]\"",
		argv[0]);
	return TCL_ERROR;
    }
    result = GetAddress(machPtr, argv[1], &address, &isReg);
    if (result != TCL_OK) {
	return result;
    }

    /*
     * Parse flags.
     */

    if (argc == 3) {
	for (p = argv[2]; *p != 0; p++) {
	    if (*p == 'b') {
		length = 1;
	    } else if (*p == 'h') {
		length = 2;
	    } else if (*p == 'w') {
		length = 4;
	    } else if (*p == 'x') {
		format = HEX;
	    } else if (*p == 'd') {
		format = DECIMAL;
	    } else if (*p == 'B') {
		format = BINARY;
	    } else if (*p == 'c') {
		format = CHAR;
		length = 1;
	    } else if (*p == 's') {
		if (isReg) {
		    sprintf(interp->result, "can't get \"%.50s\" as string",
			    argv[1]);
		    return TCL_ERROR;
		}
		format = STRING;
		length = 1;
	    } else if (*p == 'i') {
		format = INS;
	    } else if (isdigit(*p)) {
		char *end;

		count = strtoul(p, &end, 10);
		p = end-1;
	    } else if (*p == 'v') {
		addrIsValue = 1;
	    } else {
		sprintf(interp->result, "bad flag \"%c\" in \"%.50s\" command",
			*p, argv[0]);
		return TCL_ERROR;
	    }
	}
    }

    /*
     * Enter a loop to format <location value> pairs.  Round the address
     * down to an even boundary appropriate for the output type.
     */

    if (!isReg && !addrIsValue) {
	address &= ~(length-1);
    }
    p = interp->result;
    totalSpace = TCL_RESULT_SIZE;
    while (1) {
	int value;

	/*
	 * Get the value to print.
	 */

	if (addrIsValue) {
	    value = address;
	} else if (isReg) {
	    if (address == PC_REG) {
		value = Sim_GetPC(machPtr);
	    } else if (address == NEXT_PC_REG) {
		value = INDEX_TO_ADDR(value);
	    } else {
		value = machPtr->regs[address];
	    }
	} else {
	    if (ADDR_TO_INDEX(address) < machPtr->numWords) {
		value = machPtr->memPtr[ADDR_TO_INDEX(address)].value;
	    } else if (Io_Read(machPtr, (address & ~0x3), &(value)) == 0) {
		sprintf(interp->result,
			"location \"%.50s\" doesn't exist in memory",
			argv[1]);
		return TCL_ERROR;
	    }
	    if (length == 1) {
		switch (address & 0x3) {
		    case 0:
			value >>= 24;
			break;
		    case 1:
			value >>= 16;
			break;
		    case 2:
			value >>= 8;
			break;
		}
	    } else if ((length == 2) && !(address & 0x2)) {
		value >>= 16;
	    }
	}
	if (length == 1) {
	    value &= 0xff;
	    if ((format == DECIMAL) && (value & 0x80)) {
		value |= 0xffffff00;
	    }
	}
	if (length == 2) {
	    value &= 0xffff;
	    if ((format == DECIMAL) && (value & 0x8000)) {
		value |= 0xffff0000;
	    }
	}

	/*
	 * Format the value's address, leaving a pointer to it
	 * in locString.
	 */

	locString = locBuf;
	if (addrIsValue) {
	    locString = "";
	} else if (isReg) {
	    (void) sprintf(locBuf, "%s:\t", Asm_RegNames[address]);
	} else {
	    (void) sprintf(locBuf, "%s:\t", Sym_GetString(machPtr, address));
	}

	/*
	 * Format the value itself, leaving a pointer in valueString.
	 */

	valueString = valueBuf;
	switch (format) {
	    case HEX:
		(void) sprintf(valueBuf, "0x%08x", value);
		break;
	    case DECIMAL:
		(void) sprintf(valueBuf, "%d", value);
		break;
            case BINARY: {
		int i;
		for (i = 31; i >= 0; i--) {
		    if (value & (1<<i)) {
			*valueString = '1';
			valueString++;
		    } else if (valueString != valueBuf) {
			*valueString = '0';
			valueString++;
		    }
		}
		if (valueString == valueBuf) {
		    *valueString = '0';
		    valueString++;
		}
		*valueString = 0;
		valueString = valueBuf;
		break;
	    }
	    case CHAR:
		if (isprint(value)) {
		    (void) sprintf(valueBuf, "%c (0x%x)", (char) value,
			    value);
		} else {
		    (void) sprintf(valueBuf, "0x%x", value);
		}
		break;
	    case STRING:
		valueString = GetString(machPtr, address, &length);
		break;
	    case INS:
		valueString = Asm_Disassemble(machPtr, value, address);
		break;
	}

	/*
	 * Make sure there's enough space for this value in the
	 * result buffer (grow the output buffer if necessary),
	 * then put the value into the buffer.
	 */

	spaceNeeded = (p - interp->result) + strlen(locString)
		+ strlen(valueString);
        while (totalSpace <= spaceNeeded) {
            char *newSpace;
            int spaceUsed;

            totalSpace *= 2;
            newSpace = calloc(1, (unsigned) totalSpace);
            spaceUsed = p-interp->result;
            memcpy (newSpace, interp->result, spaceUsed);
            if (dynamic) {
                free(interp->result);
            }
            dynamic = 1;
            interp->result = newSpace;
            p = newSpace + spaceUsed;
        }
	strcpy(p, locString);
	strcat(p, valueString);
	p += strlen(p);

	/*
	 * Go on to the next value, if there are any more.
	 */

	count -= 1;
	if (count == 0) {
	    break;
	}
	if (isReg) {
	    address += 1;
	    if (address >= TOTAL_REGS) {
		break;
	    }
	} else {
	    address += length;
	    if (ADDR_TO_INDEX(address) >= machPtr->numWords) {
		break;
	    }
	}
	*p = '\n';
	p++;
    }
    return TCL_OK;
}


/*
 *----------------------------------------------------------------------
 *
 * Gp_FGetCmd --
 *
 *	This procedure is invoked to process the "fget" Tcl command.
 *	See the user documentation for details on what it does.
 *
 * Results:
 *	A standard Tcl result.
 *
 * Side effects:
 *	See the user documentation.
 *
 *----------------------------------------------------------------------
 */

int
Gp_FGetCmd(clientData, interp, argc, argv)
    ClientData clientData;
    Tcl_Interp *interp;			/* Current interpreter. */
    int argc;				/* Number of arguments. */
    char **argv;			/* Argument strings. */
{
    DLX *machPtr = (DLX *) clientData;
    unsigned int address;
    int isReg, result, totalSpace, spaceNeeded;
    enum {FLOAT, DOUBLE} format = FLOAT;
    int length = 4;			/* # bytes in each value to print. */
    int count = 1;			/* # of values to print. */
    char *p;				/* Points to NULL char. at end of
					 * current result. */
    int dynamic = 0;
    char *locString, *valueString;
    char locBuf[100], valueBuf[100];

    if ((argc != 2) && (argc != 3)) {
	sprintf(interp->result,
		"wrong # args:  should be \"%.50s location [flags]\"",
		argv[0]);
	return TCL_ERROR;
    }
    result = GetAddress(machPtr, argv[1], &address, &isReg);
    if (result != TCL_OK) {
	return result;
    }

    /*
     * Parse flags.
     */

    if (argc == 3) {
	for (p = argv[2]; *p != 0; p++) {
	    if (*p == 'f') {
		format = FLOAT;
		length = 4;
	    } else if (*p == 'd') {
		format = DOUBLE;
		length = 8;
	    } else if (isdigit(*p)) {
		char *end;

		count = strtoul(p, &end, 10);
		p = end-1;
	    } else {
		sprintf(interp->result, "bad flag \"%c\" in \"%.50s\" command",
			*p, argv[0]);
		return TCL_ERROR;
	    }
	}
    }

    /*
     * Enter a loop to format <location value> pairs.  Round the address
     * down to an even boundary appropriate for the output type.
     */

    if (!isReg) {
	address &= ~3;
    }
    p = interp->result;
    totalSpace = TCL_RESULT_SIZE;
    while (1) {
	int value[2];
	double *pd = (double *)&(value[0]);
	float *pf = (float *)&(value[0]);

	/*
	 * Get the value to print.
	 */

	if (isReg) {
	    switch (address) {
	    case PC_REG :
	    case NEXT_PC_REG :
		sprintf(interp->result, "Cannot print in floating point format");
		return TCL_ERROR;
	    default :
		value[0] = machPtr->regs[address];
		if (((format == FLOAT) && (address > 63)) ||
		    ((format == DOUBLE) && ((address < 32) || (address > 63)))) {
			sprintf(interp->result, "Cannot print in floating point format");
			return TCL_ERROR;
		} else if ((format == DOUBLE) && (address % 2)) {
			sprintf(interp->result, "Misaligned double floating point register");
			return TCL_ERROR;
		}
		if (format == DOUBLE)
		    value[1] = machPtr->regs[address + 1];
		break;
	    }
	} else {
	    if (ADDR_TO_INDEX(address) < machPtr->numWords) {
		value[0] = machPtr->memPtr[ADDR_TO_INDEX(address)].value;
		if (format == DOUBLE) {
		    value[1] = machPtr->memPtr[ADDR_TO_INDEX(address+4)].value;
		}
	    } else if (Io_Read(machPtr, (address & ~0x3), &(value[0])) == 0) {
		sprintf(interp->result,
			"location \"%.50s\" doesn't exist in memory",
			argv[1]);
		return TCL_ERROR;
	    }
	}

	/*
	 * Format the value's address, leaving a pointer to it
	 * in locString.
	 */

	locString = locBuf;
	if (isReg) {
	    (void) sprintf(locBuf, "%s:\t", Asm_RegNames[address]);
	} else {
	    (void) sprintf(locBuf, "%s:\t", Sym_GetString(machPtr, address));
	}

	/*
	 * Format the value itself, leaving a pointer in valueString.
	 */

	valueString = valueBuf;
	switch (format) {
	    case FLOAT:
		(void) sprintf(valueBuf, "%f", *pf);
		break;
	    case DOUBLE:
		(void) sprintf(valueBuf, "%lf", *pd);
		break;
	}

	/*
	 * Make sure there's enough space for this value in the
	 * result buffer (grow the output buffer if necessary),
	 * then put the value into the buffer.
	 */

	spaceNeeded = (p - interp->result) + strlen(locString)
		+ strlen(valueString);
        while (totalSpace <= spaceNeeded) {
            char *newSpace;
            int spaceUsed;

            totalSpace *= 2;
            newSpace = calloc(1, (unsigned) totalSpace);
            spaceUsed = p-interp->result;
            memcpy (newSpace, interp->result, spaceUsed);
            if (dynamic) {
                free(interp->result);
            }
            dynamic = 1;
            interp->result = newSpace;
            p = newSpace + spaceUsed;
        }
        strcpy(p, locString);
	strcat(p, valueString);
	p += strlen(p);

	/*