cis-lclient05:~/2012/system>more exit.s
# Text segment begins
.section .text
   .globl _start
# Program entry point
    _start:
/* Return value */
       movl  $2, %ebx
# For sys_exit system call set %eax to 1
       movl  $1, %eax
# Call the OS with an "int" instruction
       int   $0x80
cis-lclient05:~/2012/system>more runexit
#!/bin/sh -e
#
echo on termination, enter \"echo \$?\"
as -o exit.o exit.s
ld -o myexit exit.o
myexit
cis-lclient05:~/2012/system>runexit
on termination, enter "echo $?"
cis-lclient05:~/2012/system>echo $?
2
cis-lclient05:~/2012/system>






cis-lclient05:~/2012/system>more exit.s
# Text segment begins
.section .text
   .globl _start
# Program entry point
    _start:
/* Return value */
       movl  $2, %ebx
# For sys_exit system call set %eax to 1
#      movl  $1, %eax
# Call the OS with an "int" instruction
#      int   $0x80
cis-lclient05:~/2012/system>


wonderw:~/cis72/syscalls>more exit2.s
# Text segment begins
.section .text
   .globl _start
# Program entry point
   _start:
/* Return value */
      movl  $2, %ebx
# Code number "1" for system call "sys_exit"
      movl  $1, %eax
# Call the OS with an "int" instruction
      int   $0x80
# Could replace last two instructions with "sys_exit

wonderw:~/cis72/syscalls>more runexit2
#!/bin/sh -e
#
echo on termination, enter \"echo \$?\"
as -o exit2.o exit2.s
ld -o exit2   exit2.o
exit2
wonderw:~/cis72/syscalls>runexit2
on termination, enter "echo $?"
wonderw:~/cis72/syscalls>echo $?
2
wonderw:~/cis72/syscalls>