10 EXEC &H6C00
20 ORG 490
30 ALL
40 @ECHO PSHS U,A,B,X,Y
50 CLRA:STA $FF02
60 LDB #32
70 @NOYO BITB $FF00
80 BNE @NOYO
90 LDX #$8000
100 @KEYBD LEAX -1,X
110 BNE @KEYBD
120 JSR $89AA
130 JSR $8E83
140 STX >$FE
150 JSR $89AA
160 JSR $8E83
170 STX >$FC
180 LDY >$FE
190 LDA #128
200 @BLK STA ,Y+
210 LEAX -1,X
220 BNE @BLK
230 LDX >$FC
240 LDY >$FE
250 CLR $FF39
260 CLR $FF38
270 LDA #47
280 STA $FF39
290 ORCC #$50
300 CLRB:JSR $BD41
310 LDA $FF23:ORA #8:STA $FF23
320 STA $FFDF
330 LDA $FF38
340 LDX >$FC
350 LDB #32
360 @QUACK TST $FF39
370 BPL @QUACK
380 LDA ,Y:STA $FF20
390 LSRA:STA >$FB:LDA $FF38:LSRA:ADDA >$FB
400 STA ,Y+
410 BITB $FF00:BEQ @OUT
420 LEAX -1,X
430 BNE @QUACK
440 LDX >$FC
450 LDY >$FE:BRA @QUACK
460 @OUT STA $FFDE
470 PULS U,A,B,X,Y,PC
480 END @ECHO