PaulF, thanks, now clear almost all! especially difference between push/pop and 16-bit indexing.

but jsr/rts are still 'exceptions'.

BRK do even 3 push, but have only 2 dead cycles (1 for single byte instruction and 1 push related) while JSR have 1 dead cycle for 2 push

same for RTS/RTI pair.

$13 $03 - undocumented SLO ($03),Y, equivalent of ASL ($03),Y + ORA ($03),Y. so code result depend on content of $03/$04

02,12,02,32,42,52, 62,72,92,B2,D2,F2 known as KIL, they completely stop cpu, block even NMI

In 1-6 collected all dead cycles throw all 256 opcodes, including undocumented (except KIL codes of course). Maybe I found incorrect explanation of them, but list is full

Each 6502 instruction takes so many cycles as number of R/W operations plus sometimes some dead cycles. I heard that first 6502 models even on dead cycles did garbage R/W operations. I tried to systematize all kinds of dead cycles and ask you to correct my wrong assumptions.

1. All single-byte ...