DIAG6 $ D #
(
dz@
< vdu(N)
F D,D$,B,byte,item,lbyte
P item=1 N
Z D$
dD$,1)="@" B=2 B=1
n D=(D$)
x2(D$)>64 [OPT PASS:LDA D:JSR OSWRCH:]:t`@
D<0 D=((D) &FFFF)+1
byte=D 256:form
B=2 byte=D 256:form
item
form
) byte<>lbyte [OPT PASS:LDA #byte:]
[OPT PASS:JSR OSWRCH:]
lbyte=byte
OSWRCH=&FFEE:OSBYTE=&FFF4
SCR=&70
START 1000
PASS=0 3 3
" P%=START
,
6
@
J vdu(29)
Td 22,2,18,0,132,16,18,0,3,25,4,500@,500@,25,1,200@,0@,25,81,0@,-200@,25,1,-200@,0@,25,81,0@,200@
^
h
[OPT PASS
r&.BEGIN \ start at screen pos &3000
| LDA #&00
STA SCR
LDA #&06
STA SCR+1
.SCROLL
LDA #&13
JSR OSBYTE
LDA #&0D
STA &FE00
LDA SCR
STA &FE01
LDA #&0C
STA &FE00
LDA SCR+1
STA &FE01
CLC
LDA#&51
&
STA&77
0
JSRadd
:LDA&78:STA SCR
DLDA&79:STA SCR+1
N \ (78/79) and (SCR/SCR+1)
O*\ point to the start of scr mem
vJSR shuffle
JMP SCROLL
\
\
\
.add
LDA SCR+1:STA&79:LDA SCR:CLC
ADC&77
STA&78
BCC addret
LDA SCR+1:CLC:ADC#&01
CMP#&10:BNE addend
LDA#&06
.addend:STA&79
.addret:RTS
.sub
LDA SCR+1:STA&79:LDA SCR:SEC
SBC&77:STA&78
BCS subret
LDA SCR+1:SEC:SBC#&01
CMP#&5:BNE subend
LDA#&0F
.subend:STA&79:.subret:RTS
\
\
\
z6.shuffle \ assumes current screen addr is in 78/79
JSR getaddr
JSR storetop
ALDX #&1F \ copy loop starts with 2nd and ends before the last
.copyloop
+LDA&78:STA&88:LDA&79:STA&89:JSR incaddr
LDY#&07
.move
LDA(&78),Y
STA(&88),Y
DEY
BPL move
DEX
BNE copyloop
RTS
JSR incaddr:JSR retrtop
RTS
\
\
\
:.getaddr:ASL&78:ROL&79:ASL&78:ROL&79:ASL&78:ROL&79:RTS
g.incaddr:CLC:LDA&78:ADC#&80:STA&78:LDA&79:ADC#&02:CMP#&80:BMI incret:SEC:SBC#&50:.incret:STA&79:RTS
\
.storetop:LDY#&07
.loopst
LDA(&78),Y
STA&60,Y
DEY
BPL loopst
RTS
.retrtop:LDY#&07
.looprt
LDA&60,Y
STA(&78),Y
DEY
BPL looprt
RTS:]
PASS
tSS
;" ";~?&79;~?&78
&78
?&78
~?&78
&78
&78
~?&78
&78
&78
?&78
?&78
&78
&78
?&78
?&78
;~?&78
;~?&78
"SWRCH