readme_testsetjmp

This is the demo source code for embedded VxWorks, which include severl functions. The function sour

FILE LIST -
             testSetjmp.c

DESCRIPTION -
	     Test routines for setjmp and longjmp.
	     These functions are useful for dealing with errors and interrupts
	     encountered in a low-level subroutine of a program.

	     setjmp: saves the calling environment in a jmp_buf argument for
	     later use by longjmp.
	     int setjmp(jmp_buf env);

	     longjmp: performs non-logical goto by restoring the saved 
             environment.
	     void longjmp(jmp_buf env, int val);
	     After longjmp() is completed, program execution continues as 
             if the corresponding call of setjmp() just returned the value val.

	     jmpbuf: an array type suitable for holding the information 
             needed to restore a calling environment.

	     RETURN VALUES
	     setjmp: From a direct invocation setjmp returns a zero. Froms a 
             call to longjmp, it returns a  non zero value specified as 
             an argument to longjmp().

	     longjmp: This routine does not return to its caller. Instead,
	     it causes setjmp() to return val, unless val is zero; in that 
             case setjmp() returns 1.

	     To run this code invoke the function testsetjmp().

RUNNING DEMO -
	     Place the testSetjmp.c file in your <Tornado> dir. Depending on
	     the target you have, define the CPU in your compile line and use
	     the Makefile in the BSP dir. to compile.

TESTED ON -  Host/Target : Solaris 2.5.1 /mv1604
	     VxWorks     : 5.3.1

EXAMPLE COMPILE LINE - 
	     make CPU=PPC604 testSetjmp.o

% make testSetjmp.o
ccppc -B/petaluma1/mayur/tor101-ppc/host/sun4-solaris2/lib/gcc-lib/ 
-mstrict-align -ansi -nostdinc -O2 -fvolatile -fno-builtin -fno-for-scope 
-Wall -I/h   -I. -I/petaluma1/mayur/tor101-ppc/target/config/all 
-I/petaluma1/mayur/tor101-ppc/target/h 
-I/petaluma1/mayur/tor101-ppc/target/src/config 
-I/petaluma1/mayur/tor101-ppc/target/src/drv -DCPU=PPC604  -DMV1600 
-DTARGET_DIR="\"mv1604\""   -c testSetjmp.c

OUTPUTS/LOGFILE -

On VxWorks target:
==================

-> ld <testSetjmp.o
value = 834248 = 0xcbac8
-> testsetjmp()
value = 0 = 0x0

The Output on Console:
======================
In case 0 
calling function jmto which makes a call to longjmp
with its second arg = 0 which causes setjmp to return a 1.
 
  PRESS ENTER TO CONTINUE ...

  In case 1 
  calling function jmpto which makes a call to longjmp
  with its second arg = 2 which causes setjmp to return a 2.
   
  PRESS ENTER TO CONTINUE ...

  In case 2 
  In case 0 of case 2
  calling function jmpto which makes a call to longjmp
  with its second arg = -7  which causes setjmp to return a -7.
     
  PRESS ENTER TO CONTINUE ...

  In case -7 of case 2 
  calling function jmpto which makes a call to longjmp
  with its second arg = 3  which causes setjmp to return a 3.
       
  PRESS ENTER TO CONTINUE ...

  In case 3 
  longjmp(b1, 5):- makes the corresponding call of setjmp() to return a value 
  of 5, i.e,
  the program execution goes back to the setjmp() function in case 2 and then 
  causes the switch to case 5.
  In case 5 of case 2  
  returning execution to main program.
	 
  PRESS ENTER TO CONTINUE ...

  SUCCESS testing setjmp