Date   : Thu, 19 May 2005 09:49:42 +0100
From   : Richard_Talbot-Watkins@...
Subject: Re: [RE: BBC/ Master] BASIC Routines

Peter Craven wrote:

> RE: MASTER COMPUTER
> 1. Does anyone know the entry point address for the various Basic
> Routines, e.g. SQR(x), SIN(x) in the MASTER computer?  Does anybody
> know how tom implement/ use them from assembly language? Does
> anybody know of references for these as they are not in Advanced
> Master User Guide.

These used to be on the 8bit Software site (now defunct... is it coming
back?), but Google seem to have it cached (at least for the moment) at:

http://66.102.9.104
/search?q=cache:DkrEgOizRxcJ:www.8bs.com/basic/basic4.htm+bbc+basic-iv&hl=en

Get it while it lasts!

(There are also full disassemblies linked from that page, so you may be
able to convince Google to load its cached versions of those too).

> 2. Does anyone know how to use the Sheila address &00, &01 for
> control of screen (rather than using VDU23,0,12,... & VDU23,0,13,...)
> on the MASTER COMPUTER? I have entered many manipulations of the
> screen start address, but with some bizarre results only.

Exactly the same as on a BBC B.

Instead of
VDU 23,0,reg,val,0,0,0,0,0,0

use
?&FE00 = reg : ?&FE01 = val

Remember that when setting the screen address, you need to use the address
you want divided by 8.

e.g. to set screen start to &4800, use:

?&FE00 = 12 : ?&FE01 = (&4800 DIV 8) DIV 256
?&FE00 = 13 : ?&FE01 = (&4800 DIV 8) MOD 256

or simply

?&FE00 = 12 : ?&FE01 = 9
?&FE00 = 13 : ?&FE01 = 0

Hope that helps,
Rich


**********************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
postmaster@...

This footnote also confirms that this email message has been checked
for all known viruses.

**********************************************************************
Sony Computer Entertainment Europe