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Last time around cd-w made a comment that led me to doing a test rewrite of one of the ball reposition kernels:

Could always enhance the driver to include a "fast jump" feature.

JMP FastJump would be detected and the 2 byte address is pulled from ARM memory instead of the ROM. Similar to how fast fetch works.

So like Fast Fetch where we turned this:

 lda #<DS_SIZE      ; 2  2 sta CTRLPF         ; 3  5

Fast Jump would turn this:

 jmp FASTJUMP       ; 3  3

For a 10 cycle savings. If we could update the other 2 HMxx registers (so HMM0 and HMM1 during a ball reposition kernel) then we the STA HMCLR is no longer needed, which yields up another 3 cycles. With that in mind, I worked up another test rewrite which resulted in this: