8-Bit Software

The BBC and Master Computer Public Domain Library

Back to 8BS Or Back to Disassembly


Page Last Altered:

8F00 OLD

Submitted by Steve Fewell

Description:

Call routine &9BA6 to check that the statement terminates with a ':', '<cr>' or 'ELSE' character (Syntax error
if not).
Set pointer &37-&38 to point to PAGE (high byte from location &18, and low byte = &00).
Store #&00 to the second byte of the program ((&37-&38) + Y (1)).
Call routine &BDE5 to check that the program at the address PAGE can be read correctly & is a valid program, 'Bad
program' if not.
Jump to &8F83 to prompt for the next command line input.
Note: The rest of the command line is ignored even if an 'ELSE' or ':' character terminated the statement.


Disassembly for the OLD routine

8F00   032 166 155 20 A6 9B JSR &9BA6 Check end of Statement
8F03   165 024 A5 18 LDA &18
8F05 8 133 056 85 38 STA &38
8F07 d7 100 055 64 37 STZ &37
8F09   169 000 A9 00 LDA#&00
8F0B 7 145 055 91 37 STA (&37),Y
8F0D   032 229 189 20 E5 BD JSR &BDE5 Check program can be read correctly ('Bad program' message if not)
8F10 q 128 113 80 71 BRA 113 --> &8F83 Initialise & prompt for next command line

 


 Back to 8BS
Or