Acorn BBC Master 65C102, Руководство пользователя

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IMPORTANT: It is only the filing systems that recognise these '
extended' addresses. Current versions of BASIC an HI-BASIC make no
such distinction. Only the memory in the co-processor can be directly
accessed from BASIC. This means that using the ?,! and $ indirection
operators to access memory locations in the I/O processor from the
co-processor doesn't work, for example:
?&FFFF2000=&55 <RETURN>
will put the value &55 into memory location &2000 in the co-processor
and not into the location &2000 in the I/O processor as specified by
the leading FFFFs.
The same applies to saving and loading BASIC programs. If you save a
BASIC program to disc or cassette from the microcomputer, executing a
*INFO will display addresses with leading FFs. Saving a BASIC program
from the co-processor and executing a *INFO will display addresses
with leading 00s. However, BASIC will always load either program into
whichever processor is currently running BASIC.
It is possible to read and write to memory locations in the I/O
processor memory, this is done using OSWORD calls 5 and 6. OSWORD
calls are dealt with in the REFERENCE MANUAL Part 1. A more advanced
description of TUBE communication techniques is contained within the
ADVANCED REFERENCE MANUAL.
The 65C102 co-processor support disc
The disc supplied with the 65C102 contains 3 pieces of software,
these are:
HiBASIC
HiEDIT
Printer buffer utility
Hi languages
HiBASIC and HiEDIT are the same languages BASIC and EDIT that are
already resident in your machine. They only differ from the inherent
versions in the position that they expect to occupy within the memory
map.
If we consider the memory map of the microcomputer without a co-
processor attached (fig.2), we can see that BASIC normally resides
between &8000 and &BFFF. If BASIC were allowed to do this within the
co-processor, it would substantialy reduce the amount of RAM available
to the users programs. HiBASIC is supplied to overcome this
situation, it does so by locating itself between addresses &B800 and
&F7FF in the co-processor thereby allowing the user to maximise the
RAM available. HiEDIT, in this respect, acts in exactly the same way
as HiBASIC.
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