a E i - Commodore Is Awesome

T
program h was the tedious wait involved
in e loading some types of program.
wanted m to try and use Nick Hampshire's
a
Fast-save routine (published in
the February 1986 edition of Your
i
Commodore) to make fast loading
n
personal copies of any of my own
programs. i To do this I needed to be
able
n
to extract details of programs
From c their headers.
e The Header-Reader program is
quite n simple and makes use of
locations t $0333-$0346 (819-836) which
in i the Plus/4 and C16 are used as a
cassette v tape buffer. Locations $0333
and e $0334 give the start address of the
program f to be loaded, in low-byte
high-byte form, and locations $0335
o
and $0336 give the end address.
Locations
r
$0337 to $0346 contain the
w
16 characters which make up the
r
program name. The header is read by
use i of command OPEN 1 in tine 10.
t
• Line i
1 Set n up screen colours.
g
5 Clear screen, print title.
t
8 Instruction h
to position tape at
header.
e
• Get key press to continue.
10 Open Channel 1 to read header.
15 Clear screen, print title.
18-20 Print contents of locations 819-
838 ($0333-$0346).
30 Translate locations $0337 to $0346
into filename and print.
C/16/PLUS/4 PROGRAM
Tape Head
Reader
Now you can find out more about how your programs
are stored.
By D.A. Gardner
40-60 Convert the low-byte high-byte
address in locations $0333 and $0334
to give the start address of program in
decimal and print.
70-90 Convert the low-byte high-byte
address in locations $0335 and $0336
to give the end address of program in
decimal and print.
92 Subtract the start address from the
end address to give program length
and print.
95 If the start address of the program is
$1001 this is often an indication that
the program is Basic rather than a
book of code. This line communicates
that possibility.
96-98 Option of reading another
header or terminating the program.
PROGRAM: IARE HEADER
0 RED HEADER
-
NER
READER
1 COLOR0,16:COLOR4,6,COLDR1,1
B
5 SCNCLR:CHAR,12,0,"CRVSON)HEADE
R READERCRUSOFFr:PRINT
Y
8 0 CHAR,O,S,"POSITION . 6 A R
TAPE AND TH
EN D PRESS ANY KEYEDOWN)CODWW"
9 SETKEYJS
10 OPEN1
15 SCNCLR:CHAR,12,0,"CRUSDN3HEAD
ER READEKRUSOFE)":PRINT
18 PRINT"C00WN3BY1E5 813
RINI -
20 838:":P F O R I
-
EXTI
0 P R I N T
8 1 9 T 0 8
, FORP
34-8 : P R I
P R. I N T "
N1PEE
CNEXTIPRINT"CRUSOFFJ"
CDOWN B23T
40 K(I);:N
1 ASHEXSCPEEX(820)):8$..HEXSCPE
EK(815)) 1PILEN 0898
4AME
:PRI
RI
NT"E
SS
R1JS
( O N ) '
P
YOUR COMMODORE january 1987
94
Variables
.1$ For GETKEY,
A$ To contain the low-byte
component of the hex start and end
addresses.
BS To contain the high-byte
component of the hex start and end
addresses.
C$ The combined high-byte start
address.
D$ The command high-byte low-byte
end address.
S The decimal start address.
E The decimal end address.
In FOR-NEXT loop.
50 cs-mips(As,3.2)-1-minsces,3,2)
55 5..OECCCS)
60 PRINT;PRINT"(DOWN3START ADORE
SS - "is
70 A S
.
EX(821))
.
80 KEX 0
9
85
S -
E••DEC(DS)
( .
90 PRINI"CDOWNJEND
P E
ADDRESS
ME"; X E
I ( 8
D92 22)) SPRINT"EDOWN/PROGRAM
LENSTH
( r AB
S .
S SS . . , HI EF
C V
9 . ()BRAM X , S2C IS PROBABLY BASIC":ELSEPRI
NT"EDOWNOPROGRAM
) "1001"
PIS E PROBABLY CODE"
+ THENP M
98 CHAR.6,2e,"READ ANOTHER HEADE
IRINT" R? D(Y/N)"
97 S E D( SETKEYJS
8O
W N
,
HEN97 9 1 P, 3R
99
IEJS"Y"A
, 2 IFJS"Y"THENRUNS:ELSEEND
)
NDJS"N"T
1