MultiPC: a multi-program manager for SHARP pocket computers

This small but powerful machine code program manages up to ten BASIC programs residing simultaneously in memory on your SHARP pocket computer. Each of the ten BASIC programs can be independently run, edited, CLOADed from tape, CSAVEd, MERGEd and CHAINed.

Benefits:

• stores up to 10 BASIC programs simultaneously in memory
• variables and arrays retain their value after switching programs
• the machine code and programs reside on a RAM card, when present
• removing and inserting a RAM card retains the machine code and programs

Do not:

• switch programs with the CALL command from within a running program
• use TEXT, unless you go back to BASIC before switching programs

The following instructions use a cassette interface (CE-126P or CE-124). If you do not have a cassette interface, then type over the BASIC installer code and RUN (instead of DEF-A) to verify it and install.

SHARP PC-1350 with 16KB RAM card

Installation:

Play the multi16.wav file and CLOAD then press DEF-A to install. This shows: *123456789 with 10 program slots available and the current slot is 0.

Usage:

CALL 8240 shows the 10 program slots with digits 0 to 9 indicating available slots and _ for used slots. The current program slot switched to is *.

CALL 8240,0 switch to program 0, CALL 8240,1 switch to program 1, and so on up to program 9.

To clear a program slot just make it the current slot and enter NEW.

CALL 8240,NEW clears all 10 programs.

To make this easier and avoid costly mistakes when entering the calling address, in RESERVE MODE define the S (switch) key:

S: CALL 8240,

SHARP PC-1350 with 8KB RAM card

Installation:

Play the multi8.wav file and CLOAD then press DEF-A to install. This shows: *123456789 with 10 program slots available and the current slot is 0.

Usage:

CALL 16432 shows the 10 program slots with digits 0 to 9 indicating available slots and _ for used slots. The current program slot switched to is *.

CALL 16432,0 switch to program 0, CALL 16432,1 switch to program 1, and so on up to program 9.

To clear a program slot just make it the current slot and enter NEW.

CALL 16432,NEW clears all 10 programs.

To make this easier and avoid costly mistakes when entering the calling address, in RESERVE MODE define the S (switch) key:

S: CALL 16432,

SHARP PC-1350 without a RAM card

Installation:

Play the multi0.wav file and CLOAD then press DEF-A to install. This shows: *123456789 with 10 program slots available and the current slot is 0.

Usage:

CALL 24624 shows the 10 program slots with digits 0 to 9 indicating available slots and _ for used slots. The current program slot switched to is *.

CALL 24624,0 switch to program 0, CALL 24624,1 switch to program 1, and so on up to program 9.

To clear a program slot just make it the current slot and enter NEW.

CALL 24624,NEW clears all 10 programs.

To make this easier and avoid costly mistakes when entering the calling address, in RESERVE MODE define the S (switch) key:

S: CALL 24624,

Converting BAS to WAV files

I used the excellent PocketTools to convert BASIC source code to wav files:

bas2img --pc=1350 --level=8 switch16.bas
bin2wav --pc=1350 switch16.img

For developers

The target machine and RAM card choice is defined in target.h, for example the PC-1350 with 16KB card:

__RAM_SLOT1__ =  16
.include "pc1350.h"

To assemble the code, you need the AS61860 assembler and linker, see:

• https://www.qsl.net/yt2fsg/pocket/pocket_asm.html
• http://shop-pdp.net/ashtml/asxxxx.php

The ihx2bas tool included with this project converts IHX format to a BASIC bootloader program.

The pc1350.h file is sourced and extended from the PShell project:

• https://edgar-pue.tripod.com/sharp/pshell.html