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copperkid · 31 March 2010, 12:27

#303<<8 should be a shift 8 bits to the left

303 == $12f, so #$12f<<8 becomes #$12f00

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

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)

31 March 2010, 12:27	#4
copperkid Registered User Join Date: Feb 2010 Location: Germany Posts: 30	#303<<8 should be a shift 8 bits to the left 303 == $12f, so #$12f<<8 becomes #$12f00 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 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)