Post by thread:why won't this code fragment work ????????????????

---------- > Van: spam_OUTkerzerTakeThisOuTCST.CO.ZW > Aan: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU > Onderwerp: why won't this code fragment work ????????????????? > Datum: woensdag 11 februari 1998 7:51 > > word set one > call test > word set two > call test > word set three > call test > > test > call word > return The first thing your 'test' routine does is 'call word' , wich executes 'set three' hereby overruling your 'set one' command. Next, your commands 'test: call word, word: set three, call test' are building a loop that will never end ! And, whats more, your stack will grow explosively ! (all those call's and no return's ...) In a micro-controller you will mostly not notice this, because the stack sits in a seperate piece of memory and will only overwrite its own 'return' data when overflowing. Try something like : word set three test {do any output} return > one > return > two > return > three > return > > The set command seems to only remember the last one, ie it calls three all > the time. I had it workin, but I don't know how I did it. > > Gordon Greetz, Rudy Wieser

The "SET" command is an assembler command (i.e. has effect at assemble time, *not* at run time). As you have found, the assembler preprocessor expands your source code to: call test call test call test test call three The value of "word" when the assembler reaches "test" is "three". It looks like you are trying to have the destination of the call at "test" determined at run time. With the 16Cxx family, all CALLs are hard-coded. You can emulate this by doing something like this (WARNING: not tested and barely proof-read!): ;-- Set call destination to "one" movlw high(one) ;Load upper byte of address into PC Latch High movwf PCLATH movlw low(one) ;Load lower byte of address into temp register movwf CALLDEST call test zzz1 ... (more code here) movlw high(two) ;Load upper byte of address into PC Latch High movwf PCLATH movlw low(two) ; Load lower byte of address into temp reg ister movwf CALLDEST call test zzz2 ... (more code here) test ... (put some code here that does not change PCLATH) movf CALLDEST,0 movwf PCL ;Jumps (chains) to desired routine one ...(some code here) return ;Will return to zzz1 two ...(some code here) return ;Will return to zzz2 On Wednesday, February 11, 1998 1:51 AM, kerzerKILLspamCST.CO.ZW [SMTP:.....kerzerKILLspam.....CST.CO.ZW] wrote: {Quote hidden}> word set one > call test > word set two > call test > word set three > call test > > test > call word > return > > one > return > two > return > three > return > > The set command seems to only remember the last one, ie it calls three all > the time. I had it workin, but I don't know how I did it. > > Gordon >