Introduction to Computer Systems * Pima Community College * CIS135 -- 4.3 Run an assembly program

4.3 Run an assembly program

4.3 Run an assembly program

If you are using gort copy over two files from the class area. The class area on gort is /home/cis135. To copy a file use the cp command. Remember that you need to specify a destination. A "." specifies the current directory. You can also use wild cards. An "*" matches any number of any characters. So if you do:

cp ~CIS135/*.S .

gortwill copy the two assembly language files from the class area to your current directory.

Use ftp to get two files from ftp://lt.tucson.az.us/pub/. The files are sample.S and sbr.S.

In the file sample.S there are instructions on how to assemble the code using the FSF gcc compiler.

Follow the instructions.

/* Louis Taber   11/1/97  PCC                         */
/*                                                    */
/*  Sample program for assembly language              */
/*  subroutines on Linux.  These are compiled         */
/*  and linked as follows:                            */
/*                                                    */
/*  If compiled/assembled together.                   */
/*       gcc -nostdlib -o sample sbr.S sample.S       */
/*                                                    */
/*  If complies as separate modules.                   */
/*       gcc -nostdlib -o sample sbr.o sample.S       */
/*                                                    */
/*  To assemble the library to object                 */
/*       gcc -c sbr.S                                 */
/*  this will create the object file for the library  */


#define FILE_STDIN    $0     /* file handle for stdin      */
#define FILE_STDOUT   $1     /* file handle for stdout     */
#define FILE_ERROR    $1     /* file handle for stderror   */

#define LINUX_SYS     $0x80  /* interrupt for system calls */

                             /* Values for system calls    */
                             /* defined in unistd.h        */
#define LINUX_EXIT   $1
#define LINUX_READ   $3
#define LINUX_WRITE  $4
 
        .file           "sample.S"
        .version        "01.01"
        .data
head:   .string         "Sample gcc/linux assembly"
                        " language program\n\n"
request:
        .string         "Please input a hexadecimal number: "
eop:    .string         "\nThe program is done.\n"
hex:    .string         "       Hexadecimal: "
dec:    .string         "       Decimal:  "
        .text
        .align 16
        .globl          _start
        .type           _start,@function

_start:  xorl            %ebp,%ebp        /* clear bp */
        andl            $0xfffffff8,%esi  /* align stack to */
                                          /* 8 byte boundry */
	
        movl    $head,%esi
        call    pstring

        movl    $request,%esi      /* print out program heading */
        call    pstring
        call    getline            /* get input string */
        call    char2num           /* convert to number */

        movl    $dec,%esi
        call    pstring
        call    pnumd              /* print in decimal */
        call    new_line           /* keep output neat */

        movl    $hex,%esi
        call    pstring
        call    pnumnl             /* print in hex */
        call    new_line           /* keep output neat */

        movl    $12,%ecx           /* load loop counter */
        movl    $1,%eax            /* starting point */
        movl    $2,%ebx            /* for multiply */
loopa:  call    pnumd              /* print decimal number */
        movb    $' ',%dl           /* get a space */
        call    putchar            /* print the space */
        call    pnumnl             /* print number in hex */
        mull    %ebx               /* factorial series */
        inc     %ebx	
        loopl   loopa


        movl    $eop,%esi
        call    pstring

        movl    LINUX_EXIT,%eax    /* exit code */
        int     LINUX_SYS          /* call OS */
        hlt                        /* exit should not return */

        .align	16

        .comm	d,1,1
	.ident	"GCC: (GNU) 2.7.2.1"

The subroutines can be found at: ftp://lt.tucson.az.us/pub/sbr.S.

Run the program, it puts out a factorial series.

sample

Redirect the programs output through the tee command so that you can print it.

sample | tee temp
lpr temp

Label it with

Your-Name
Lab 4.3: assembly
TABER CIS135

Place the lab in the instructor hand-in box in BUS R6E, the "terminal room".

Instructor: ltaber@pima.edu ** My new Home at GeoApps in Tucson ** The Pima College Site ** The Mad Dr. G.'s home page on phred.

4.3 Run an assembly program