; 16B looks like columns ; zero page locations HGR_SHAPE = $1A HGR_SHAPE2 = $1B GBASL = $26 GBASH = $27 ; ROM calls HGR2 = $F3D8 HGR = $F3E2 HPOSN = $F411 XDRAW0 = $F65D XDRAW1 = $F661 tiny_xdraw: ; loads at E7 (HGR_SCALE) which is $20 (jsr instruction) jsr HGR2 ; Hi-res, full screen ; 3 ; Y=0, A=0 after this call ; we really have to call this, otherwise it won't run ; on some real hardware jsr HPOSN ; set screen position to X= (y,x) Y=(a) ; saves X,Y,A to zero page ; after Y= orig X/7 ; A and X are ?? tiny_loop: ldy #$e3 inx ; X is 1 lda #2 ; ROT=2 jsr XDRAW0 ; XDRAW 1 AT X,Y ; Both A and X are 0 at exit ; Z flag set on exit ; Y varies beq tiny_loop ; bra