BBC BASIC: Difference between revisions

Revision as of 15:28, 12 August 2005

Revision as of 04:57, 17 August 2005

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BASIC I, the original version, available on BBC A and BBC B, was superseded by BASIC II which added <code>OPENUP</code> and <code>OSCLI</code> keywords, along with offset assembly and bug fixes.

ABASIC III, the release supplied with the BBC B+, was produced in both a UK version and a [[United States|U.S.]] market version, known as BASIC III, was produced for Acorn's abortive attempt to enter the cross Atlantic computer market. - apartApart from a few bug fixes the only differencechange from BASIC II was that the <code>COLOUR</code> command incould also be spelled <code>COLOR</code>: regardless of which was input, the UK version always listed it as <code>COLORCOLOUR</code> in, the US version (thoughas both<code>COLOR</code>. versions acceptedThis eitherwas spellingthe asonly input)difference between the two versions.

BASIC IV, also known as CMOS BASIC, available on the BBC Master and BBC Master Compact machines, was changed to use the new intructions available in the 65C12 processor, reducing the size of the code and therefore allowing the inclusion of <code>LIST IF</code>, <code>EXT#</code> as a statement, <code>EDIT</code>, <code>TIME$</code>, <code>ON PROC</code>, | in <code>VDU</code> statements and faster floating point. Bug fixes were again included.

With the move to the 32 bit [[ARM_architecture|ARM]] CPU and the removal of the 16kB limit on the BASIC code size many new features were added. BASIC V version 1.04 was 61kB long and included many new commands such as <code>WHILE-ENDWHILE</code>, <code>IF-THEN-ELSE-ENDIF</code>, <code>CASE-OF-WHEN-OTHERWISE-ENDCASE</code>, <code>RETURN</code> parameters in proceduces, local arrays, procedure libraries (<code>LIBRARY</code>, <code>INSTALL</code> and <code>OVERLAY</code>), <code>LOCAL DATA</code> and <code>LOCAL ERROR</code> handlers, a relative <code>RESTORE</code>, array operations, new operators, <code>TRACE STEP</code>, along with commands for the new sound system, mouse, graphics. The graphics commands were entirely backwards compatible, the sound less so (for example, the <code>ENVELOPE</code> keyword from BASIC V onwards is a command which takes fourteen numeric parameters and does nothing.) The in-line in 6502 assembler was replaced by an [[ARM_architecture|ARM]] assembler. BASIC V was said, by Acorn, to be "certainly the fastest interpreted BASIC in the world" and "probably the most powerful BASIC found on any computer".

BASIC VI is a version of BASIC V that supports 8 byte format real numbers (according to IEEE standard 754) as opposed to the standard 5 byte format introduced in BASIC I.