From: William Levak (wlevak_at_cyberspace.org)
Date: 2002-11-20 23:44:41
On Wed, 20 Nov 2002, Rhialto wrote:
> A trick for BASIC programs that wish to distinguish between old and new
> basic is to PEEK() some location in the BASIC interpreter. The old basic
> interpreter always returned 0 for PEEK() between some addresses,
> corresponding to the BASIC interpreter. PEEK(50003) was a popular
> location I think, because in the new basic it contains 1.
original Basic contained 0
upgrade Basic 1
Basic 4.0 160
There were also several variations of these:
There was a replacement ROM for original Basic.
Upgrade Basic has at least 2 different screen editor ROMs.
The original B ROM for Basic 4.0 was replaced and is very rare.
There are a number of different screen editor ROMs for Basic 4.0
To determine if you have the replacement for original Basic:
POKE1018,173:POKE1021,133:POKE1022,2:POKE1023.96
POKE1019,193:POKE1020,197:SYS1018:PRINTPEEK(2)
The original ROM will give 1, the replacement will give 152.
You need this routine because all locations in original BASIC are
protected and will return 0.
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