The Woz Wonderbook (1977) [pdf]
digibarn.com
digibarn.com
It's on page 51, we can replace:
LSR
BCC EVEN
LSR
BCS ERR
CMP #$22
BEQ ERR
AND #$7
ORA #$80
with: LSR
BCC EVEN
ROR
BCS ERR
CMP #$A2
BEQ ERR
AND #$87
saving 2 bytes !At this time, I spent several months optimizing the Basic ROM from Microsoft, but I never released anything.