*       test halftone RAM
*       write target with $01; write all others with 0 and f, verify target,
*       repeat, writing left shifted data to target, until 16 patterns done
*       repeat with next target
	.text
testblt:
	move.w  sr,srsave0
	move.w  #$2700,sr	
        lea     blt2,a0
tst_ht:  
	moveq   #0,d0           ;starting pattern for target
ht_256:  move    d0,(a0)         ;write target 
        move    #$ffff,d1       ;surround pattern
        moveq   #0,d2
*       fill background
fil_ht0: lea     blt2,a1
        moveq   #15,d7          ;# of cells
	
fil_ht1: 
	cmpa.l    a0,a1
        beq     fil_ht2
        move    d2,(a1)
        move    d1,(a1)         ;write all others
fil_ht2: adda    #2,a1
        dbra    d7,fil_ht1
*       verify target
*        cmp     (a0),d0         ;check target
	move.w  (a0),d3
	cmp.w   d3,d0
        bne     ht_rf

        add     #$101,d0
        cmp     #$100,d0
        bne     ht_256           ;256 combinations

        adda    #2,a0           ;next target
        cmpa.l  #blt2+32,a0
        bne     tst_ht
        bra     testbltr

ht_rf:   
	move.w  switch,d6
.if TOS=0
        move    #red,palette
.endif
	lea     bltmsg1,a5
	bsr	dspmsg
	bsr	crlf
	bsr	puta0	
	bsr	dspspc
	bsr	putd0w
	bsr	dspspc
	bsr	putd3w
	bset    #ebltf,flag	

testbltr:
	move.w  srsave0,sr
	btst    #ebltf,flag
	rts