The Zooom trick
The Zooom Trick is an enhancement to the main loop of Blur-style
scanners, which was first used in Zooom... by John Metcalf (Core Warrior
70). A Blur-style scanners works by scanning and clearing simultaneously
in the same loop, with the scan directing the clear to whatever it finds.
Zooom... uses a trick which improves on the basic Blur-style scan loop by
only including the clear in the loop once something has actually been found.
This is achieved by having the clear attack positioned just above the scan
loop as shown below:
mov *sBmb, >sGat ; out of the scan loop
sLoo:sub #step, #step*numb
jmz.f sLoo, @sLoo ; a-field mutates
Once something has been detected by the scan loop, some part of our
scanner needs to extend the loop to include the clear attack. In the
example, we simply need to decrement the a-field of the jmz.f
instruction:
mov *sBmb, >sGat ; included in the scan loop
sLoo:sub #step, #step*numb
jmz.f sLoo-1, @sLoo ; a-field modified
Some examples of warriors using the Zooom Trick are:
Warrior | Author | Hill |
Zooom... | John Metcalf | 94nop |
Stalker | P.Kline | 94nop |
Shadow Seeker | John Metcalf | 88 |
Enough is Enough! | John Metcalf | 94 |
Dark Energy | F^2 | 94nop |
Cold as November Rain... | John Metcalf | 88 |
Tiny Zooom... | John Metcalf | tiny |
|