.include 'jaguar.inc' .globl Clear Clear: ; OK lets just set up enough Blitter stuff to do a block draw ; This means set A1_FLAGS to ; Contiguous data ; 16 bit per pixel ; width of 56 pixels ; add increment move.l #PITCH1|PIXEL16|WID256|XADDPIX,d0 move.l d0,A1_FLAGS ; Point A1BASE to the data move.l #$20000,d0 move.l d0,A1_BASE ; Set the pixel point to 0,0 move.w #0,d0 ; y swap d0 move.w #0,d0 ; x move.l d0,A1_PIXEL ; Set fractional pixel pointer move.w #0,d0 ; y swap d0 move.w #0,d0 ; x move.l d0,A1_FPIXEL ; Set up the step size to -256 in x ; 1 in y ; The x step requires that the pixel pointer by move.w #1,d0 ; y swap d0 move.w #(-256),d0 ; x move.l d0,A1_STEP ; Set up the fractional step size to 0 in x ; 0 in y move.w #0,d0 ; y swap d0 move.w #0,d0 ; x move.l d0,A1_FSTEP ; Set up Counters register to 256 in x write long to clear upper ; 256 in y, or in y as a word move.w #200,d0 ; y swap d0 move.w #256,d0 ; x move.l d0,B_COUNT ; Put some data in the blitter for it to write ; This is a cheat I am using all 0 so there is ; no need to word swap move.l #0,d0 move.l d0,B_PATD move.l #0,d0 move.l d0,B_PATD+4 ; Now Turn IT ON !!!!!!!!!!!!! ; NO SOURCE DATA ; NO OUTER LOOP ; Turn on pattern data ; Allow outer loop update move.l #PATDSEL|UPDA1,d0 move.l d0,B_CMD rts