The BBC and Master Computer Public Domain Library

9741 GCOL

Submitted by Steve Fewell

Description:

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.
Push &2A (the LSB of the Integer value - i.e. the first GCOL parameter) to the stack.

Call &96AC to check for a comma ('Missing ,' error if not found) and get the integer result at the BASIC text Pointer B
location (issuing 'Type mismatch' error if a String value was found).
Call &9B96 to check that the Statement (at BASIC Text Pointer B location) terminates correctly ('Syntax' error is issued
if end of statement marker is not found).

Output character 18 (to start a VDU 18 - GCOL command).
Pop the first Integer from the stack and [&979B] output the character (this is the first parameter to the GCOL command).

Next, output the contents of location &2A (The IWA LSB, which contains the second GCOL parameter), this completes the
GCOL parameters, and the Operating system now executes the GCOL command.
Lastly, jump to &9005 to start processing the next program statement.

Disassembly for the GCOL routine