; CHRONON ; a concrete poem & a 32-byte c64 demo ; by nom de nom ; ; To start, SYS 4096 ; ; This one ends cleanly after ~1 minute 13 seconds w/ a proper rts, ; letting you see and read the text. You can restart with SYS 4096. ; Visuals change on three time scales: ; Text color (fastest, character by character when varying), ; Whether text/border color is varying (every 128 characters), ; Background color/VIC-II mode changes (every 256 characters). ; There is sound -- indeed, music. .word $1000 *=$1000 jsr $f1ca ; could also use $ffd2, the CHROUT vector dex lda $a09e,x ; RESLST, list of BASIC keywords sta $d3f0,x ; set SID registers (& other stuff!) randomly bmi $1000 ; if x>127 goto beginning stx $0286 ; set COLOR, foreground text color sta $d020 ; set EXTCOL, border color register bne $1000 ; if x is not 0 goto beginning inc $d011 ; SCROLY, a VIC-II register to change video modes dec $d021 ; change BGCOL1, background color register 1 iny bne $1000 ; if y is not 0 goto beginning rts