One thing I've found... annoying if wasting a bunch of ROM space doing noting. That is, burning cycles for timing purposes but at the cost of ROM space. Ideal solution would be various flavour NOPs, all using 1 byte but consuming 2-a bunch of cycles. Unfortunately that's just not the case.
So these are the instructions and instruction combinations that I've been using to waste cycles. Anybody have any better ones?
--------------------------------------------------------------------------
1 Cycle (0 or 1 byte)
.w (Make a zero page instruction an absolute instruction)
or
,x (Make a zero page or absolute instruction an indexed instruction)
Notes: .w adds a byte of code.
,x needs x=0 (can also use y register)
--------------------------------------------------------------------------
2 Cycles (1 byte)
NOP
--------------------------------------------------------------------------
3 Cycles (2 bytes)
STA $ZeroPage
or
LDA $ZeroPage
or
DOP $ZeroPage
Notes: STA/LDA Destroys register or RAM location (use scratch variable)
--------------------------------------------------------------------------
4 Cycles (2 bytes)
NOP
NOP
--------------------------------------------------------------------------
5 Cycles (2 bytes)
dec $ZeroPage
Notes: Destroys RAM location (use scratch variable)
--------------------------------------------------------------------------
6 Cycles (3 bytes)
NOP
NOP
NOP
--------------------------------------------------------------------------
7 Cycles (2 bytes)
PHA
PLA
Notes: Don't overflow stack
--------------------------------------------------------------------------
8 Cycles and more - combinations of the above, or loop.
[You can use PHA/PHP (1 byte 3 cycles) or PLA/PLP (1 byte 4 cycles) alone but you have to be carefull not to mess up your stack (PLP/PHA would be usefull if you have no stack!)]
Chris...
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