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Unread 16-02-2002, 12:00
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Greg Ross Greg Ross is offline
Grammar Curmudgeon
AKA: gwross
FRC #0330 (Beach 'Bots)
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Quote:
Originally posted by Ian W.
If you're out of variable space, then you're pretty much out of choices to make.
Not exactly true.

We have run out of variable space several times, and have continued adding variables!

There are a couple of strategies we use when such a situation arises: Firstly, you may have some variables which are only used for intermediate values in calculations. For these, you may use "scratch" variables which can be reused similarly in other sections of the code.

You can also swap data to and from scratchpad RAM. For instance, you are filtering your joystick inputs, and you need to keep a "previous filtered value" from one loop iteration to the next, but that value is only needed in one small section of the code. Here's how you can use scratchpad RAM for this data:
Code:
' =====================
'ScratchPad RAM memory map:

PREV_FILTERED_X con 0
PREV_FILTERED_Y con 1

...


' =====================
'Filter the joystick inputs

get PREV_FILTERED_X, scratch1 ' Reads prev value into scratch1

... ' Calculate new filtered value

put PREV_FILTERED_X, newFilteredX

...
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Greg Ross (The Grammar Curmudgeon formerly known as gwross)
S/W Engineer, Team 330, the Beach 'Bots
<--The Grammar Curmudgeon loves this cartoon.
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