Source code for BASIC

From: Bill Sudbrink <bill_at_chipware.com>
Date: Fri Feb 18 09:16:00 2000

> > >Looking through the first few feet of "real data"...
> > >
> > >No high bits, the first few bytes are:
> > >00111011 x3b ';' (was hoping for the start of an assembly comment)
> > >00110010 x32 '2' (nope, looks like some sort of hex...)
> > >00110000 x30 '0'
> > >01000001 x41 'A'
> > >00110000 x30 '0'
> > >00110000 x30 '0'
> > >00110000 x30 '0'
> > >00110011 x33 '3'
> > >00111001 x39 '9'
> > >01000001 x41 'A'
>
> This looks to me like MOS Technologies checksum hex format,
> as used on the KIM-1.
>
> > That makes some sense, "20" is the 6502 opcode for a JSR (jump to
> > subroutine). The next two bytes are presumably the subroutine's
> > address, and "39" is the 6502 opcode for an AND abolute,Y instruction.
>
> Not if it's MOS Tech. hex! The first two digits are the
> length of the block (in hex), then four digits of address,
> then the hex for the data block. There'll be a checksum on
> the end. In this case, we've got a 32-byte block (20 hex)
> starting at address A000.

This sounds right. There is "8k basic _at_ a000" written on a scrap of
paper that was with these tapes.
Received on Fri Feb 18 2000 - 09:16:00 GMT