main.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.

/* 
 * main.c --
 *
 *  Main program for "dlxview" simulator for DLX architecture.
 *
 *  This file is part of DISC.  It was modified by Yinong Zhang 
 *  ([e-mail]) from the file "main.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 <stdio.h>
#include <tcl.h>
#include <tk.h>
#include <signal.h>
#include "dlx.h"
#include "purdue.h"

/*
 * Declarations for various library procedures and variables (don't want
 * to include tkInt.h or tkConfig.h here, because people might copy this
 * file out of the Tk source directory to make their own modified versions).
 */

extern void		exit ();
extern int		isatty ();
extern int		read ();
extern char *		strrchr ();


/*
 * Global variables used by the main program:
 */

static Tk_Window mainWindow;	/* The main window for the application.  If
				 * NULL then the application no longer
				 * exists. */
static Tcl_Interp *interp;	/* Interpreter for this application. */
static Tcl_DString command;	/* Used to assemble lines of terminal input
				 * into Tcl commands. */
static int tty;			/* Non-zero means standard input is a
				 * terminal-like device.  Zero means it's
				 * a file. */
static char errorExitCmd[] = "exit 1";
static DLX *machPtr;

/*
 * Command-line options:
 */

static int synchronize = 0;
static char *fileName = NULL;
static char *name = NULL;
static char *display = NULL;
static char *geometry = NULL;


static Tk_ArgvInfo argTable[] = {
    {"-file", TK_ARGV_STRING, (char *) NULL, (char *) &fileName,
	"File from which to read commands"},
    {"-geometry", TK_ARGV_STRING, (char *) NULL, (char *) &geometry,
	"Initial geometry for window"},
    {"-display", TK_ARGV_STRING, (char *) NULL, (char *) &display,
	"Display to use"},
    {"-name", TK_ARGV_STRING, (char *) NULL, (char *) &name,
	"Name to use for application"},
    {"-sync", TK_ARGV_CONSTANT, (char *) 1, (char *) &synchronize,
	"Use synchronous mode for display server"},
    {(char *) NULL, TK_ARGV_END, (char *) NULL, (char *) NULL,
	(char *) NULL}
};

/*
 * Declaration for Tcl command procedure to create demo widget.  This
 * procedure is only invoked if SQUARE_DEMO is defined.
 */

extern int SquareCmd _ANSI_ARGS_((ClientData clientData,
	Tcl_Interp *interp, int argc, char *argv[]));

/*
 * Forward declarations for procedures defined later in this file:
 */
static void		Prompt (Tcl_Interp *, int);
static void		StdinProc (ClientData, int);
static void 		Interrupt(int);


/*
 *----------------------------------------------------------------------
 *
 * main --
 *
 *	Top-level procedure for dlxview simulator.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Tons:  read the user manual for details.
 *
 *----------------------------------------------------------------------
 */

int
main(argc, argv)
    int argc;				/* Number of arguments. */
    char **argv;			/* Array of argument strings. */
{
    char *p, *msg;
    int code;
    char *tcl_RcFileName;


    interp = Tcl_CreateInterp();


    /*
     * Parse command-line arguments.
     */

    if (Tk_ParseArgv(interp, (Tk_Window) NULL, &argc, argv, argTable, 0)
	    != TCL_OK) {
	fprintf(stderr, "%s\n", interp->result);
	exit(1);
    }
    if (name == NULL) {
	if (fileName != NULL) {
	    p = fileName;
	} else {
	    p = argv[0];
	}
	name = strrchr(p, '/');
	if (name != NULL) {
	    name++;
	} else {
	    name = p;
	}
    }


    /*
     * If a display was specified, put it into the DISPLAY
     * environment variable so that it will be available for
     * any sub-processes created by us.
     */

    if (display != NULL) {
	Tcl_SetVar2(interp, "env", "DISPLAY", display, TCL_GLOBAL_ONLY);
    }

    /*
     * Initialize the Tk application.
     */

#if defined(TK40)
    mainWindow = Tk_CreateMainWindow(interp, display, name, "Tk");
    if (mainWindow == NULL) {
      fprintf(stderr, "%s\n", interp->result);
	   exit(1);
    }
#endif
    if (synchronize) {
	   XSynchronize(Tk_Display(mainWindow), True);
    }
#if defined(TK40)
    Tk_GeometryRequest(mainWindow, 200, 200); 
#endif



    /*
     * Set the "tcl_interactive" variable.
     */

    tty = isatty(0);
    Tcl_SetVar(interp, "tcl_interactive",
	    ((fileName == NULL) && tty) ? "1" : "0", TCL_GLOBAL_ONLY);

    /*
     * Add a few application-specific commands to the application's
     * interpreter.
     */


    /*
     * Invoke application-specific initialization.
     */

    if (Tcl_Init(interp) != TCL_OK) {
	fprintf(stderr, "Tcl_Init failed: %s\n", interp->result);
    }
    if (Tk_Init(interp) != TCL_OK) {
	fprintf(stderr, "Tk_Init failed: %s\n", interp->result);
    }


    tcl_RcFileName = "~/.dlxviewrc";

    machPtr = Sim_Create(interp);  
    (void) signal(SIGINT, Interrupt);

    Tk_DefineBitmap(interp, Tk_GetUid("purdue"), (char *)pur_bits, pur_width, pur_height);


#ifdef SCRIPT
    code = Tcl_VarEval(interp, "source dlxview.tcl", (char *) NULL);
	if (code != TCL_OK) {
	    goto error;
	} 
#else 
    Script_Read(interp);
#endif 

    Sim_Initialize(machPtr);

    /*
     * Set the geometry of the main window, if requested.
     */

    if (geometry != NULL) {
	code = Tcl_VarEval(interp, "wm geometry . ", geometry, (char *) NULL);
	if (code != TCL_OK) {
	    fprintf(stderr, "%s\n", interp->result);
	}
    }

    /*
     * Invoke the script specified on the command line, if any.
     */

    if (fileName != NULL) {
	code = Tcl_VarEval(interp, "source ", fileName, (char *) NULL);
	if (code != TCL_OK) {
	    goto error;
	}
	tty = 0;
    } else {
	/*
	 * Commands will come from standard input, so set up an event
	 * handler for standard input.  If the input device is aEvaluate the
	 * .rc file, if one has been specified, set up an event handler
	 * for standard input, and print a prompt if the input
	 * device is a terminal.
	 */

/*
	if (tcl_RcFileName != NULL) {
	    Tcl_DString buffer;
	    char *fullName;
	    FILE *f;
    
	    fullName = Tcl_TildeSubst(interp, tcl_RcFileName, &buffer);
	    if (fullName == NULL) {
		fprintf(stderr, "%s\n", interp->result);
	    } else {
		f = fopen(fullName, "r");
		if (f != NULL) {
		    code = Tcl_EvalFile(interp, fullName);
		    if (code != TCL_OK) {
			fprintf(stderr, "%s\n", interp->result);
		    }
		    fclose(f);
		}
	    }
	    Tcl_DStringFree(&buffer);
	}
*/
	Tk_CreateFileHandler(0, TK_READABLE, StdinProc, (ClientData) 0);
	if (tty) {
	    Prompt(interp, 0);
	}
    }
    fflush(stdout);
    Tcl_DStringInit(&command);

    /*
     * Loop infinitely, waiting for commands to execute.  When there
     * are no windows left, Tk_MainLoop returns and we exit.
     */

    Tk_MainLoop();

    /*
     * Don't exit directly, but rather invoke the Tcl "exit" command.
     * This gives the application the opportunity to redefine "exit"
     * to do additional cleanup.
     */

    Tcl_Eval(interp, "exit");
    exit(1);

error:
    msg = Tcl_GetVar(interp, "errorInfo", TCL_GLOBAL_ONLY);
    if (msg == NULL) {
	msg = interp->result;
    }
    fprintf(stderr, "%s\n", msg);
    Tcl_Eval(interp, errorExitCmd);
    return 1;			/* Needed only to prevent compiler warnings. */
}


/*
 *----------------------------------------------------------------------
 *
 * StdinProc --
 *
 *	This procedure is invoked by the event dispatcher whenever
 *	standard input becomes readable.  It grabs the next line of
 *	input characters, adds them to a command being assembled, and
 *	executes the command if it's complete.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Could be almost arbitrary, depending on the command that's
 *	typed.
 *
 *----------------------------------------------------------------------
 */

    /* ARGSUSED */
static void
StdinProc(clientData, mask)
    ClientData clientData;		/* Not used. */
    int mask;				/* Not used. */
{
#define BUFFER_SIZE 4000
    char input[BUFFER_SIZE+1];
    static int gotPartial = 0;
    char *cmd;
    int code, count;

    count = read(fileno(stdin), input, BUFFER_SIZE);
    if (count <= 0) {
	if (!gotPartial) {
	    if (tty) {
		Tcl_Eval(interp, "exit");
		exit(1);
	    } else {
		Tk_DeleteFileHandler(0);
	    }
	    return;
	} else {
	    count = 0;
	}
    }
    cmd = Tcl_DStringAppend(&command, input, count);
    if (count != 0) {
	if ((input[count-1] != '\n') && (input[count-1] != ';')) {
	    gotPartial = 1;
	    goto prompt;
	}
	if (!Tcl_CommandComplete(cmd)) {
	    gotPartial = 1;
	    goto prompt;
	}
    }
    gotPartial = 0;

    /*
     * Disable the stdin file handler while evaluating the command;
     * otherwise if the command re-enters the event loop we might
     * process commands from stdin before the current command is
     * finished.  Among other things, this will trash the text of the
     * command being evaluated.
     */

    Tk_CreateFileHandler(0, 0, StdinProc, (ClientData) 0);
    code = Tcl_RecordAndEval(interp, cmd, 0);
    Tk_CreateFileHandler(0, TK_READABLE, StdinProc, (ClientData) 0);
    Tcl_DStringFree(&command);
    if (*interp->result != 0) {
	if ((code != TCL_OK) || (tty)) {
	    printf("%s\n", interp->result);
	}
    }

    /*
     * Output a prompt.
     */

    prompt:
    if (tty) {
	Prompt(interp, gotPartial);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * Prompt --
 *
 *	Issue a prompt on standard output, or invoke a script
 *	to issue the prompt.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A prompt gets output, and a Tcl script may be evaluated
 *	in interp.
 *
 *----------------------------------------------------------------------
 */

static void
Prompt(interp, partial)
    Tcl_Interp *interp;			/* Interpreter to use for prompting. */
    int partial;			/* Non-zero means there already
					 * exists a partial command, so use
					 * the secondary prompt. */
{
    char *promptCmd;
    int code;

    promptCmd = Tcl_GetVar(interp,
	partial ? "tcl_prompt2" : "tcl_prompt1", TCL_GLOBAL_ONLY);
    if (promptCmd == NULL) {
	defaultPrompt:
	if (!partial) {
	    fputs("(dlxview) ", stdout);
	}
    } else {
	code = Tcl_Eval(interp, promptCmd);
	if (code != TCL_OK) {
	    Tcl_AddErrorInfo(interp,
		    "\n    (script that generates prompt)");
	    fprintf(stderr, "%s\n", interp->result);
	    goto defaultPrompt;
	}
    }
    fflush(stdout);
}


/*
 *----------------------------------------------------------------------
 *
 * Interrupt --
 *
 *	This procedure is invoked when the interrupt key is typed:
 *	it causes the simulation to stop.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Causes simultor to stop after next instruction.
 *
 *----------------------------------------------------------------------
 */

static void
Interrupt(dumb)
    int dumb;
{
    fprintf( stderr, "interrupt\n" );
    Sim_Stop(machPtr);
}


/*
 *----------------------------------------------------------------------
 *
 * Main_QuitCmd --
 *
 *	This procedure is invoked to process the "quit" Tcl command.
 *	See the user documentation for details on what it does.
 *
 * Results:
 *	None:  this command never returns.
 * * Side effects: 
 *	The program exits.
 *
 *----------------------------------------------------------------------
 */

/* ARGSUSED */
int
Main_QuitCmd(clientData, interp, argc, argv)
    ClientData clientData;
    Tcl_Interp *interp;			/* Current interpreter. */
    int argc;				/* Number of arguments. */
    char **argv;			/* Argument strings. */
{
    exit(0);
    return TCL_OK;			/* Never gets executed. */
}