100 SEI
110 LDA 788     ; FIRST POINT BRK VEC
120 STA 790     ; AT IRQ SERVICE CODE
130 LDA 789
140 STA 791
150 LDA #<IRQSRV; THEN POINT IRQ VEC
160 STA 788     ; AT YOUR SWITCH
170 LDA #>IRQSRV
180 STA 789
190 CLI
200 RTS
220 IRQSRV =*   ; INTERRUPT WEDGE
230 LDA #0
240 STA $FF00   ; SET BANK 15 CONFIG
250 BRK         ; SERVICE IRQ THRU BRK
260 NOP
270 PLA         ; OLD CONFIG ON STACK
280 STA $FF00   ; RESTORE IT
290 PLA         ; REGISTERS TOO
300 TAY
310 PLA
320 TAX
330 PLA
340 RTI         ; RETURN FROM INTERRUPT