Product specifications

PRESS PLAY AND RECORD ON TAPE
AND HIT ANY KEY WHEN READY
and will begin saving or loading data the moment it is executed. This means that any
programmer who wishes to make use of this routine must write his or her own
prompts.
;
;DATAIO – SEE DESCRIPTION ABOVE FOR ROUTINE SUMMARY
;
; PARAMETERS REQUIRED ON ENTRY
; SEE DESCRIPTION ABOVE
;
; AF, BC, DE, HL REGISTERS AFFECTED ON EXIT
;
DATAIO: LD HL,10000 ;Start address at which data
;is to be saved from
LD DE, 100 ;Number of bytes to be saved
LD A,0 ;Set ‘save/load’ option byte
LD (£FD68),A ;Type to save
CALL £0AEE ;Save data bytes
RET ;Return to calling routine
An edited version of the tape routine INOUT is listed within appendix G. It is not
dependent on BASIC and can be used in applications where BASIC is not required to
be in use.
Adding Data Tape Save/Load Commands to BASIC
6.3
This routine has been designed so that it can be added to any BASIC program or
written as the core to a new BASIC program and will add two new commands listed
below.
i. USER,L,<string$> - Load data string
ii. USER,S,<string$> - Save data string
Once the code has been written into the BASIC program it must be executed before
the new form of USER is typed in via the editor otherwise the command USER will be
rejected.
it has been designed so that it will save and load strings only.
An important point to note is that all strings must have a length of some sort when
using this routine. If we were saving a string A$ which was equal to “” (Null), its
apparent length would be zero but internally this would be treated as 64K. In order to
give null strings a length they can be assigned with the value CHR$(0) or a spce.
??? (Insert rest of data tape save/load section here).