On Wed, 16 Feb 2000 16:49:57 -0500
CLASSICCMP_at_trailing-edge.com wrote:
> >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 format is also used on the UK101, and is accepted by
many types of EPROM programmer.
> Tim.
--
John Honniball
Email: John.Honniball_at_uwe.ac.uk
University of the West of England
Received on Thu Feb 17 2000 - 08:03:40 GMT