Code Optimization

Kye

Hello, all I've been busting my head on how to do something in asm much more simply, but I just can't seem to get it done.

Here's the code..

                        muxnz   keyBuffer,          #1                  ' Backup Z flag.
                                                
                        cmp     keyArrayCounter,    #2 wz               ' Wait a little while to synchronize.      
if_nz                   cmp     keyArrayCounter,    #6 wz               '
if_nz                   cmp     keyArrayCounter,    #10 wz              '    
if_nz                   cmp     keyArrayCounter,    #14 wz              '
if_nz                   cmp     keyArrayCounter,    #18 wz              '
if_nz                   cmp     keyArrayCounter,    #22 wz              '
if_z                    waitcnt keyTimeBuffer,      clockWait           '
                                                                            
                        test    keyBuffer,          #1 wz               ' Restore Z flag.  

Basically, I need to use waitcnt for a state machine at specific times·in my code. The piece above is run inside a loop that loops 26 times. Every four loops I need to execute the waitcnt which is what this code does.

Now, I want to make it more optimized by using the c flag only so I don't need to backup the z flag since I'm using it within the loop. The problem is however, that there's a sweet spot. The code above executes that sweet spot. To say, waitcnt must only be executed on the 22, 18, 14, 10, 6, 2 parts in the loop. Note that the loop counts down from 26 so the execution of the coditional for 2 is last and 26 is first.

I can't seem to figure out how to do this with the c flag...

Any ideas?

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Nyamekye,

lonesock

Untested, off the top of my head:

mov tmp, keyArrayCounter
sub tmp, #2
and tmp, #3
tjnz tmp, #skip_pause
waitcnt keyTimeBuffer, clockWait
skip_pause

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lonesock
Piranha are people too.

Kye

Wow, I think that will work, thanks!

Any other ideas anyone?

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Nyamekye,

lonesock

YW, and maybe this will work:

   mov tmp, keyArrayCounter
   rev tmp, #30
   djnz tmp, #:skip_pause
   waitcnt keyTimeBuffer, clockWait
:skip_pause

Reversing the lower 2 bits of tmp will zero out all upper 30 bits, and will leave a 1 in tmp if the original value would have been a 2. Then the DJNZ jump to :skip_pause if the value of tmp was not 1.

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lonesock
Piranha are people too.

mpark

Wow Lonesock! Nice one!

lonesock

Thanks.

* bows *


[noparse][[/noparse]8^)

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lonesock
Piranha are people too.