Create and rotate multiple BASIC programs in your SHARP pocket computer

SHARP pocket computers of the 80s can store and run several BASIC programs together when loaded with MERGE from a cassette tape. The last MERGEd program can be edited. This is not convenient. There is a better solution.

Prolly is a small but powerful machine code program that manages a collection of MERGEd BASIC programs for your SHARP pocket computer.

• allows you to create any number of BASIC programs as MERGEd and start writing them on the machine itself without having to MERGE from a cassette tape
• allows you to rotate a collection of MERGEd BASIC programs in memory, making the previous program the last MERGEd (the last MERGEd program can be edited)
• does not interfere with the MERGE, LOAD/CLOAD and SAVE/CSAVE commands
• Prolly and the BASIC MERGEd programs reside on a RAM card, when present
• removing the RAM card retains Prolly and the BASIC programs on the RAM card, which can be inserted to restore Prolly and the programs

For example, suppose we have one program "A" already in memory:

1 "A" REM my first program
2 PRINT "I am program A"

To add a new program, CALL 32818 (PC-1360) to create a new MERGEd program consisting of one line with a quote:

1 "A" REM my first program
2 PRINT "I am program A"
1 "

Note that the new line 1 " starts a new program that is independent of the previous programs, even when the listing appears to be continuous. To verify, LIST only lists the last merged program's first lines. In this case:

LIST
1 "

Complete the new program by adding a label "B" and the rest of the code:

1 "A" REM my first program
2 PRINT "I am program A"
1 "B" REM my second program
2 PRINT "I am program B"

Executing RUN will run program "B", because it is the last MERGEd just as LIST will only list program "B".

Program "A" is executed with RUN "A". Program "A" stops at line 2 and will not run program "B". Programs are internally separated when MERGEd. Separate programs can call each other using GOTO and GOSUB with labels or string expressions. RESTORE of labelled data in another program is also possible. In this way, libraries of routines and data can be created and shared among several programs.

CALL 32820 (PC-1360) rotates the programs, effectively switching "A" and "B":

1 "B" REM my second program
2 PRINT "I am program B"
1 "A" REM my first program
2 PRINT "I am program A"

Program "A" can now be edited, which was not possible before the rotation:

1 "B" REM my second program
2 PRINT "I am program B"
1 "A" REM my first program
2 PRINT "I am the first program"

You can create as many programs as you like and rotate them. To delete the last program, use DELETE 1, (PC-1360) or enter empty line numbers (PC-1350). NEW deletes all programs. SAVE and CSAVE saves them combined. If you use PocketTools, then the MERGEd CSAVEd programs can be converted back to text.

The following instructions use a cassette interface (CE-126P or CE-124) to load the bootloader program. If you do not have a cassette interface, then you can use LOAD with the serial port of your machine, or type-in the bootloader and RUN (instead of DEF-A) to verify it.

SHARP PC-1360 with 8KB, 16KB or 32KB RAM card

Installation:

Play the prolly.wav file and CLOAD. This loads prolly.bas. Press DEF-A.

Usage:

CALL 32818 creates a new MERGEd BASIC program consisting of one line 1 ". Add a label after the quote and write the rest of the program.

CALL 32820 rotates MERGEd BASIC programs and makes the previous program the last MERGEd. The last MERGEd program can be edited.

To make this easier and avoid costly mistakes when entering the calling address, in RESERVE MODE define SHIFT-M (merge new) and SHIFT-SPC (rotate):

RESERVE MODE
M: CALL 32818
 : CALL 32820

SHARP PC-1350 with 16KB RAM card

Installation:

Play the prolly16.wav file and CLOAD. This loads prolly16.bas. Press DEF-A.

Usage:

CALL 8242 creates a new MERGEd BASIC program consisting of one line 1 ". Add a label after the quote and write the rest of the program.

CALL 8244 rotates MERGEd BASIC programs and makes the previous program the last MERGEd. The last MERGEd program can be edited.

To make this easier and avoid costly mistakes when entering the calling address, in RESERVE MODE define SHIFT-M (merge new) and SHIFT-SPC (rotate):

RESERVE MODE
M: CALL 8242
 : CALL 8244

SHARP PC-1350 with 8KB RAM card

Installation:

Play the prolly8.wav file and CLOAD. This loads prolly8.bas. Press DEF-A.

Usage:

CALL 16434 creates a new MERGEd BASIC program consisting of one line 1 ". Add a label after the quote and write the rest of the program.

CALL 16436 rotates MERGEd BASIC programs and makes the previous program the last MERGEd. The last MERGEd program can be edited.

To make this easier and avoid costly mistakes when entering the calling address, in RESERVE MODE define SHIFT-M (merge new) and SHIFT-SPC (rotate):

RESERVE MODE
M: CALL 16434
 : CALL 16436

SHARP PC-1350 without RAM card

Installation:

Play the prolly0.wav file and CLOAD. This loads prolly0.bas. Press DEF-A.

Usage:

CALL 24626 creates a new MERGEd BASIC program consisting of one line 1 ". Add a label after the quote and write the rest of the program.

CALL 24628 rotates MERGEd BASIC programs and makes the previous program the last MERGEd. The last MERGEd program can be edited.

To make this easier and avoid costly mistakes when entering the calling address, in RESERVE MODE define SHIFT-M (merge new) and SHIFT-SPC (rotate):

RESERVE MODE
M: CALL 24626
 : CALL 24628

Converting BAS to WAV files

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

bas2img --pc=1350 --level=8 prolly16.bas
bin2wav --pc=1350 prolly16.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