8-Bit Software

The BBC and Master Computer Public Domain Library

Back to 8BS Or Back to Disassembly

Page Last Altered:


Submitted by Steve Fewell


Get the result of the expression at BASIC Text Pointer A, convert the result to Integer (Type mismatch error if String),
and Set BASIC Text Pointer A to BASIC Text Pointer B value.

Call &9BA6 to check that the Statement (at BASIC Text Pointer A location) terminates correctly ('Syntax' error is issued
if end of statement marker (':', '<cr>' or 'ELSE') is not found).

Output character 17 (to start a VDU 17 - COLOUR command).
[&979B] Next, output the contents of location &2A (The IWA LSB, which contains the COLOUR number), this completes the
single-parameter COLOUR command, and the Operating System now execuites the Colour command.

Lastly, jump to &9005 to start processing the next program statement.

Disassembly for the COLOUR routine

9755 o 032 111 146 20 6F 92 JSR &926F Evaluate Expression at BASIC Text pointer A convert result to integer
9758   032 166 155 20 A6 9B JSR &9BA6 Check end of Statement
975B   169 017 A9 11 LDA#&11
975D < 128 060 80 3C BRA 60 --> &979B


 Back to 8BS