||R/W||ADR||HEXADR||NAME||DESCRIPTION||OS||DEFAULT VALUE |read/write |512,513|$0200,$0201|VDSLST|Vector to Display List Interrupt routine|both|59315/$E7B3 (a RTI instruction) Attention: * All 6502 registers have to be saved before and restored after the interrupt (before the RTI instruction). * an example to save registers and variables in the language "Action!" [Interrupts in ACTION] * The interrupt routine must end with an RTI (return from interrupt). !!Example for saving and restoring the processor registers {{{ ;we need to push to stack, first A, then X, then Y PHA ;push ACCU to Stack TXA ;transfer X to ACCU PHA ;push ACCU (now X) to Stack TYA ;transfer Y to ACCU PHA ;push ACCU (now Y) to Stack ; ;... routine goes in here ... ; ;now we need to pull from stack first Y, then X, then A PLA ;pull Y from STACK to ACCU TAY ;transfer ACCU to Y PLA ;pull X from STACK to ACCU TAX ;transfer ACCU to X PLA ;pull ACCU from STACK RTI ;end interrupt routine with ReTurn from Interrupt }}} !!Example for setting your interrupt routine * Set bit 7 in the [display list|display_list_instruction_table] line you want the interrupt to occur * clear bit 7 of [NMIEN] to disable the interrupt * set [VDSLST] to your routine * set bit 7 of [NMIEN] to enable the interrupt ---- see also: [Display List Topics|Displaylist_topics], [NMIEN], [Display List Instruction table|display_list_instruction_table]