GBASL = $26 GBASH = $27 HGR_BITS = $1C HGR_HMASK = $30 HGR_X = $E0 HGR_Y = $E2 HGR_COLOR = $E4 HGR_HORIZ = $E5 HGRPAGE = $E6 SAVEX = $FD TEMP = $FE OLD = $FF PAGE0 = $C054 PAGE1 = $C055 HGR = $F3E2 HGR2 = $F3D8 HCLR = $F3F2 HPOSN = $F411 HPLOT0 = $F457 ;; plot at (Y,X), (A) HPLOT1 = $F45A MOVE_RIGHT = $F48A HCOLOR1 = $F6F0 WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us tiny: jsr HGR2 ; clear page1 ; A is 0 after ldx #3 jsr HCOLOR1 tiny_yloop: ldy #0 ldx #0 ; XX = 0 yy_smc: lda #0 ; Y co-ord jsr HPOSN ; plot at (Y,X), (A) tiny_xloop: ; lda (GBASL),Y ; eor HGR_BITS ; and HGR_HMASK ; eor (GBASL),Y ; sta (GBASL),Y ; lda HGR_BITS ; eor (GBASL),Y ; and HGR_HMASK ; eor (GBASL),Y ; sta (GBASL),Y jsr HPLOT1 jsr MOVE_RIGHT ; trashes A cpy #39 bne tiny_xloop inc yy_smc+1 jmp tiny_yloop