Operating instructions

Tape Execute File
Create and Use
Once upon a time, a computerist wanted to convert his
integer BASIC programs to Applesoft BASIC. He read
about a great technique . but it required a disk. He did
not have a disk, but did have cassettes. Could the
technique
be modified for tape? And, what other
changes would
be required for the complete conver·
sion? Some interesting things were discovered, and are
reported here.
Allen J. Lacy
1921 Oglethorpe Avenue
Albany, GA
31707
.
J
.,
For a long time, I had been trying to
find a way to convert Integer programs
to Applesoft. So it was with great in·
terest
that I read the How to Section ti·
tied
"Disk Magic;; in Contact 5. A short
summary
follows for those who didn't
get Contact 5. It was a way to list the In-
teger programs on to disk and then load
it into Applesoft. This was done by pla-
cing
the following line in the program:
o PRINT"@ OPEN X":POKE 33,33:
PRINT"@WRITE
X":L1ST:PRINT"@CLOSE X":END
(Where @means
Control D)
When this line is entered type "RUN"
and press "RETURN". When the opera-
tion is complete, enter Applesoft and EX·
ECute the file.
The only problem with this method
January, 1980
is that I do not have a disk yet.
I started to think about how this
could be done with just a tape. During a
normal
"SAVE" both Integer and Ap-
plesoft write the program to tape the
way it is stored in memory, not the way it
is listed. The program is stored as
tokens; and since the tokens do
not
match, Applesoft cannot load Integer
programs.
So I wrote two routines which link
into the input and output hooks CSW
and KSW at $36-$39. (This article uses
"$" to indicate a hexadecimal number.)
The output routine gets each byte
as the Apple outputs it and stores it in a
buffer before the actual output. When
the Apple outputs a carriage return, the
routine writes the buffer to tape. This
continues until the Apple outputs a car·
MICRO -- The 6502 Journal
riage return as the first character, the
routine then resets the output hook.
The
buffer is 256 bytes long. This
number
was chosen because that is the
length
of the Apple's input buffer. Note
the
buffer is from $3FOO to $3FFF
(decimal 16128 to 16383). This is
because my Apple has 16K. For different
memory sizes this can be changed. If
you have
an assembler, change the
SAVE address to the values in table 1. If
you
do not have an assembler, change
the locations shown in table 2.
The input routine reads the tape
records back into memory and passes
the bytes through the
input hooks. This
continues
until a record comes in which
contains a carriage return as the first
byte, the routine then gives control back
to the keyboard.
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