Bob Ammerman [rammerman at prodigy.net] of RAm Systems says
The PIC18Cxx2 chips contain quite a few nice new features. One of the neatest is programmable access to the stack. This feature allows many powerful tricks.
- this code has _NOT_ been tested!
- all multi-byte values are little-endian
- I assume the code space never exceeds 16 bits worth (which it never will on the 242, 252, 442 or 452 chips).Exception handling (like C++) (or C's setjmp/longjmp) ; establish an exception handler CBLOCK EXCEPT_SP ENDC some_routine: ; 'establish' the exception handler push ; make room for exception handler movlw low(exception_handler) movwf TOSL,A movlw high(exception_handler) movwf TOSH,A movff STKPTR,EXCEPT_SP . . rcall another_routine ; 'tear-down' the exception handler pop ; couldn't be simpler! ; at this point we can either return, or 'fall_thru' into the ; exception handler to perform actions that are needed whether ; or not an exception occurs exception_handler: . . . return ; Returns to caller of 'some_routine' another_routine: . . call yet_another . . btfsc SOMEVALUE,somebit,A ; Exceptional condition? bra not_except ; Next two instructions 'raise' the exception movff EXCEPT_SP,STKPTR return not_except: return yet_another: . . bc oops ; Ran into trouble return ; Normal return oops: ; Next two instructions 'raise' the exception movff EXCEPT_SP,STKPTR return
|file: /Techref/microchip/18c/excepts.htm, 1KB, , updated: 2000/6/30 12:53, local time: 2018/3/20 00:37,
|©2018 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?|
<A HREF="http://techref.massmind.org/techref/microchip/18c/excepts.htm"> PIC 18C Microcontoller Program Flow Method for Exception handling</A>
|Did you find what you needed?|
Welcome to massmind.org!
Welcome to techref.massmind.org!