better coding methods to freeing active ram in small pics

[longpole001]

so as a bit of summery to date , what i have seen and do to reduce code size and ram allocation are as follows.
But this is no where near complete , but add / correct where needed !!!
1. Use the correct variable size – eg bit byte word
2. Where multi flags are required of setup myflags as a byte, with variable = myflags.0, for each flag

  Myflags var byte 
Timeout_flag_0 var  Myflags.0 
Timeout_flag_1 var  Myflags.1
Fade_flags_0     var Myflags.2 
Fade_flags_1     var Myflags.3

3. Keep variables that are used in subroutine to min and reuse in each subroutine ( don’t forget to set to 0 in each routine at start)
4. Keep Global variables to small number and to a byte
5. When doing a read such as pulsin , and using a word variable , if accuracy is not as a big issue for other processing then dont assign words to an array with the results / divide the result so a byte value in array is used

 
FOR X = 0 TO 31                  ' grab 32 incoming pulses
       PULSIN IR,1,leader          ' now measuring high-going pulse widths   ( pulsin_max set to 21600 = 108ms )
       BtnVal(x) = leader/2        ' leader divide by 2 so array Btnval(x) is byte (<255) not word value  
  NEXT X

6 where practical for code reading and structure , replace case select code with if , then statements

           if DByte[4] = $6F then                  ' Red - remote 1 
              read remotetype + Red ,STDByte[4]      ' read eeprom remote 2 location + button offset   
              STDByte[3] = (~ STDByte[4])            ' bitwise Not the value of byte4 to be byte3 
           endif
           if DByte[4] = $4F then                  ' Btn01 - remote 1 
              read remotetype + Btn01 ,STDByte[4]    ' read eeprom remote 2 location + button offset   
              STDByte[3] = (~ STDByte[4])            ' bitwise Not the value of byte4 to be byte3 
           endif
           if DByte[4] = $57 then                  ' Btn02 - remote 1 
              read remotetype + Btn02 ,STDByte[4]    ' read eeprom remote 2 location + button offset   
              STDByte[3] = (~ STDByte[4])            ' bitwise Not the value of byte4 to be byte3 
           endif
           if DByte[4] = $67 then                  ' Btn03 - remote 1 
              read remotetype + Btn03 ,STDByte[4]    ' read eeprom remote 2 location + button offset   
              STDByte[3] = (~ STDByte[4])            ' bitwise Not the value of byte4 to be byte3 
           endif

7 replace if x= 1 And y=1 then statements , with multi if statements , uses less words in compile


8. when doing a read from a table in eeprom , its better to multi reads than keep in variables
9. assigning constants with a variable name and use as the offset in lookup table and then doing a read at that location is better than using a variable for each name in the table
10 love DT_int14.bas , routines but has high hit on ram on small pics , so better to use for all interrupts for timers , IOC etc , than setting up other code to monitor interrupt flags outside of DT routines
11 math calculations , not sure , not had to do much of those where its been an issue ??

[rsocor01]

Also, check this thread out for more tips.

http://www.picbasic.co.uk/forum/show...highlight=code

[ofuzzy1]

What is your issue programming or outputting?

Ran into the same brickwall and used the onboard NV ram for stuffing the output messages.
Used the debug instead of serout/hserout it uses less space
Then Used gosub for calling the output and read the text one letter and used char+128 to indicate EOL/EOM.

The gosub used much less space using individual functions:
so if you had a lot of conditions; set them up as a matrix and work them against the matrix, calling all from the NV ram.
Amazingly ugly but did it on a bet. Even had room for a copyright

Next time just buy the larger [read better] part, they wind up being cheaper
12f1840 / 16f182x / 16f193[8/9]

Newark.com has decent pricing. [last years pricing, but you get the idea]

PIC12F683	8dip	20MHZ 2Kprog 128nvB 256EE 6I/O $1.41 or	$1.15	
PIC12F1822	8 dip	2kprog 256ram 128nvB 6 i/o	$1.20
PIC12F1840-I/P		 8 PDIP	IO6 Prog7K 256B RAM 128nvB 32MHz 3tmr  	$1.18

Using the NV -- Ofuzzy1 & W_Alarm are now text strings residing in the NV

CharBump        con $80
Ofuzzy1 data @$10,   "(C)2011 Ofuzzy1 AllRightsReserved-Not for Life Critical Use", "!" + CharBump
W_Alarm  Data        "Alarm", "_" + CharBump

gosub Print_Copyright
...

Print_Copyright:
gosub Print_SP2 : gosub CR_LF3 ': gosub CR_LF
zb= Ofuzzy1 : gosub Print_Phrase
gosub CR_LF3 ': gosub CR_LF
return

to print a phrase out use this:
ab, bb, zb are byte sized VAR

Print_Phrase:   ' Call with zb = ROM_Memory_Location [byte]
bb = 1
  Do until !BB '  = 0
    read zb, ab
    if ab > CharBump-1 then 
        ab = ab - CharBump
        bb = 0
    endif    
    debug ab
    zb= zb + 1
  loop
return

to call get the phrase ready to print use this:

Print_Copyright:
gosub CR_LF
zb= Ofuzzy1 : gosub Print_Phrase
return

Need 3 or 2 or 1 line feeds?

CR_LF3:
debug LF,cr
CR_LF2:
debug LF,cr
CR_LF:
debug CR,LF
return