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RE: [N8VEM-S100:2772] BASIC in ROM - Any Interest?

I like it




From: n8vem...@googlegroups.com [mailto:n8vem...@googlegroups.com] On Behalf Of nbreeden
Sent: Monday, March 17, 2014 6:33 PM
To: n8vem...@googlegroups.com
Subject: [N8VEM-S100:2772] BASIC in ROM - Any Interest?


I'm wondering if there is any interest in having BASIC in ROM allowing turn-key BASIC programming; if so then please read on.


One of my design goals was for my S-100 projects was to get BASIC in ROM running. I wanted to do this for several reasons:

 - It takes me back to the days of my Radio Shack Model I with BASIC in ROM

 - I find BASIC really useful for debugging boards; PEEK, POKE, INP, OUT and WAIT are really useful

 - BASIC gives me a turn key solution; turn the power on and I have the BASIC prompt

 - For quick and dirty code I find BASIC easier to use / manage


The chosen BASIC:

   I looked at the source for several BASIC interpreters and finally settled on using the NASCOM BASIC that had been ported to the "Space Time Productions" SBC. Joel Owens (http://www.joelowens.org/z80/index.html) had ported it, converted it to Console I/O, documented it and provided clean commented source on his web site. Joel gave me the go ahead to use the source for this project.


What I did:

 - One of my design goals was to use common tools to manage the code; NOTEPAD++.EXE as the editor and TASM as the assembler. I wanted to code to be compiled on a PC then using a USB EPROM programmer to program the EPROM.

 - I formatted the code so it looks clean using NOTEPAD++.EXE

 - I added code to allow it to use 16550 UARTS; this was tested using the UART on the prototype S-100 Utility (MSX2) Board.

 - I added code to allow it to use the USB serial adapter on the S-100 Serial IO Version 02 board.

 - The original code had BASIC at the bottom of MEMORY; I wanted it in high MEMORY instead so that the low memory areas are RAM based to allow CPM to run; I made edits to move it to the $E000-$FFFF address space.

 - I modified the CLS command to use ANSI escape sequences to home the cursor and clear the screen.

 - I added a HOME command to use ANSI escape sequences to home the cursor.



   There are two versions (source branches)

 - One meant to run in LOW memory targeting the EPROM socket on the S-100 Utility (MSX2) card (16550 UART).

 - One meant to run in HIGH memory on my S-100 Z-80 CPU V2 board - I had to make a minor change on the board to allow a full 8K of EPROM to be used.


BASIC's Features include:

 - Floating point maths with a full set of functions

 - For, Next, Step, Goto, Gosub, Return, Stop, On, Wait, End


 - String functions MID$, RIGHT$, LEFT$, LEN, STR$, VAL, ASC, CHR$

 - USR function



 - UPPER and LOWER case

 - Fully tokenized BASIC

 - Auto detection of MEMORY size



 - I've updated STAR TREK to run

 - I've updated HUNT THE WUMPUS to run


Still to do:

 - Fully test it

 - Add drivers for other Serial IO devices such as the Z-80 DART

 - Clean up the build environment - currently it's just a BAT file

 - Clean up the source so there is only one source code file that used #DEFINES to control how it's compiled

 - Update the BASIC documentation

 - Have more fun



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