make your code faster

[stan cartwright]

Ideas here for making your code run faster.

1- goto
for c1=1 to 100
if var(c1)=var2 then var3=1
next

for c1=1 to 100
if var(c1)=var2 then goto endfornext
next
endfornext: var3=1

2-don't use and
if var1=5 and var2=20 then

if var1=5 then if var2=20 then

3-for next vs repeat
for ptr=1 to 100
next

ptr=1
repeat 100
ptr++
end repeat

4-thinking... more goto stuff... any ideas to add?

[Anobium]

1. Use ROTATE rather than Divide or Multiply. If the sum is 2,4,8,16,32,64 etc... use ROTATE many times.
2. Use multiple for-next using Bytes rather than one for-next using a Word or Long loop variable.
3. Use a constant to set bits rather than a variable. PORTx.0 thru to PORTx.7 with a case statement uses more code but will be a lot faster than PORTx.variable

[stan cartwright]

Good tips. Cheers.

[William Roth]

When swapping nibbles in a byte variable, GCB supports the function "SWAP4". A macro is much faster, especially on a PIC, where it is literally 10 x faster. 1 instruction cycle vs 10 instruction cycles. On an AVR, the call to function and the return are eliminated making it faster as well.
(AVR section untested) .

Macro SwapNibbles(IN Swap_IN, OUT Swap_Out)
   #ifdef PIC
       SWAPF Swap_IN, W
       MOVWF Swap_OUT
   #endif

   #ifdef AVR
       'Dim Swap_IN   ;Alias SysCalcTempA
       'Dim Swap_OUT  ; Alias SysCalcTempX
       mov Swap_OUT, Swap_In
       asm swap Swap_OUT
   #endif
End MAcro

[Chris Roper]

Nice, certainly couldn't be optimized any more than that.