Quote:
Originally Posted by copperkid
given the initial
and.l #$1ff00,d0
basically the comparison is only for bits 33-16 of the value initially read in d0
why this works is a mystery to me, but I assume StingRay knows what he's doing  |
Bits 8-16 rather (VPOS). See
VPOSR and
VHPOSR documentation and you'll understand how and why it works.
Quote:
Originally Posted by copperkid
By the way, just this morning I was playing around with the exec routines to add my handler to the vertical blank interrupt, is there a lot of difference in performance?
I took and modified the code from the HRM, something on the lines of
Code:
move.l _GfxBase,a6
jsr _LVOOwnBlitter(a6)
move.l $4.w,a6
jsr _LVOForbid(a6)
moveq.l #INTB_VERTB,d0
lea VBlankServer(pc),a1
jsr _LVOAddIntServer(a6)
|
Nothing wrong with that, one advantage is that you don't have to care about acknowledging the IRQ (and thus you don't have to deal with interrupt related bugs that can occur on A4000's f.e.) because the OS does that for you.