Ah, ok.Ghislain wrote:I understand this part. My question was along the lines of if I want to turn off this interrupt routine, say like this:
Just wondering where the raster beam will be placed when "verify_display_flag" will be performed? Perhaps it will be well before it reaches the edge of the border of the first raster line anyhow.Code: Select all
verify_display_flag: LDA flag_display_routine // How many CPU cycles will be used BNE modify_display_registers // for these JMP play_music // 3 lines? modify_display_registers: // Do the background + border raster interrupt routine here // This I presume will be performed 88 times for all of the raster lines needed play_music: // Play the music here RTS
We're just talking about something like 8 cycles here - the test would be included in the interrupt routine (i.e. it will and should remain always active). The raster beam itself is at the very top of the display screen, when the test is performed - and I will have to include the test in the interrupt routine for myself - otherwise the cycle-exactness couldn't be guaranteed. You can then change the flag from the foreground process - that then will determine whether you want the extra colours (at the expense of some CPU power) or don't want/need them. The music routine will continue to work anyhow, at the same pace with or without the raster routine.
Will PM you my e-mail.