VirtuaNESの場合、
$EE9E:58 CLI
$EE9F:6C FC DF JMP ($DFFC) = $6000
$E1C7:2C 01 01 BIT $0101 = #$80
$6000:A5 FA LDA $00FA = #$00
$E1C7:2C 01 01 BIT $0101 = #$80
...(略)
$E1F6:68 PLA
$E1F7:40 RTI
$6002:29 F7 AND #$F7
......(略々)
$E1F6:68 PLA
$E1F7:40 RTI
$604F:8D 01 01 STA $0101 = #$C0
$E1C7:2C 01 01 BIT $0101 = #$C0
$E1CA:30 1E BMI $E1EA
$E1EA:50 03 BVC $E1EF
$E1EC:6C FE DF JMP ($DFFE) = $61A2
$61A1:40 RTI
$61A2:78 SEI
$61A3:08 PHP
$61A4:48 PHA
$61A5:8A TXA
$61A6:48 PHA
$61A7:98 TYA
$61A8:48 PHA
...
↑
とりあえずIRQ割り込みが1命令ごとに発生し、$6000からゆっくりとプログラムが
進むが$604Fまで行くとIRQ割り込みから抜け正常作動。