Gavin.Flower@comp.vuw.ac.nz (Gavin Flower) (05/17/91)
The following I tried sending directly, but it bounced. Not sure what if
any, documentation he has.
****Charles do you have sufficient documentation?
If not, what do you have?
And what do you want to do with the Beeb?
id <AA00546@kio.comp.vuw.ac.nz>; Thu, 16 May 91 18:54:27 +1200
Date: Thu, 16 May 91 18:54:27 +1200
From: gavin
Message-Id: <9105160654.AA00546@kio.comp.vuw.ac.nz>
To: cccph@jessica.cs.ucla.edu (Charles Hobbs)
Subject: Re: BBC microcomputer
Hi,
Yes & No! - Now mostly Arc stuff, but the
odd hard bitten Beeb (BBC) and Elk (Electron)
owner sometimes contribute!
However you have bought a good machine.
BASIC is very good. About 5* faster than that of an
Apple II or Commodore 64.
Keywords must always be in uppercase,
awkward until you get used to it, BUT
a very good idea. Keep all, except single
character, variable names, in lower case and you will not
run into key word problems that you do on
most other micros.
eg orange% = 4
this would generate an error on an Apple
as "OR" is a reserved word and the Apple
is not case sensitive!
No need to uses goto's and gosubs !!!!!
try this
10 MODE 2
20 REPEAT
30 GCOL RND(4), RND(7)
40 PLOT 85, RND(1280), RND(1024)
50 UNTIL FALSE
60 END
or this
1 MODE 1
5 GCOL 1, 2
10 MOVE 100, 100
20 DRAW 100, 200
30 DRAW 200, 200
40 DRAW 200, 100
50 DRAW 100, 100
60 END
can not remember details of GCOL
BUT one number selects the logical colour
the other the drawing action
replace, XOR, OR, AND, invert
there are 8 MODEs 0 to 7
MODE 2 has 16 logical colours 8 to 15 flash
I use MODEs 0, 1, 2 for graphics +text
and 3, 6 for text only
all grahics modes have 1280 (0...1279)
"grahical units" wide
pixels vary in size from 2*2 to 8*2 GUs
vertically 1024 (0...1023) at least on
standard tv's probably less on US NTSC
tv's !!!
NB origin is at standard position for maths
bottom left, therefore x increases to the left
and y increases vertically
has procedures - call by value
try this
10 FOR I% = 1 TO 32
20 PROC_powers(I%, 2, top%)
30 NEXT
40 END
50
60 DEF PROC_powers(num%, p1%, p2%)
70 LOCAL I%
80 FOR I% = p1% TO p2%
90 PRINT num%^I%;
100 NEXT
110 PRINT
120 ENDPROC
integers are 32 bit
try 10 PRINT 2^30
20 END
peek & poking use "?" for bytes
"!" for words (32 bit)
eg
10 MODE 6
20 DIM area% 100 :REM grab 101 bytes, area% contains address, note spaces!
30 PRINT ~area%
40 PRINT ?area%
50 PRINT !area%
60 ?area% = &FA
70 area%?1 = &DE
80 area%?2 = &BA
90 area%?3 = &BE
100 PRINT ~!area%
110 END
normally DIMs are used for arrays
eg define an array 5 by 6
least element xyz(0,0)
last element xyz(4, 5)
10 MODE 6
20 DIM xyz(4, 5) :REM NB no space between name and dimensions !!!!
30 xyz(2, 3) = 77
40 PRINT TAB(5, 10) xyz(2, 3)
50 END
floating point numbers are stored in 5 bytes
4 byte mantisa
1 byte for the exponent
try typing in ("*" indicate a MOS command)
*FX0
*HELP
most things done on other 8-bit machines using pokes
are done using *FX a, x, y
a, x, y are byte sized values
try this
10 PRINT ~HIMEM
20 *FX254
30 PRINT ~HIMEM :REM you now have lost 16K
40 END
also look at
LOMEM
TOP
PAGE
programs are saved as
SAVE "name"
loaded, but not run
LOAD "name"
loaded and run
CHAIN "name"
programs in memory are simply
RUN
try
*key9OLD|mRUN|m
then press Function key 9 "f9"
the symbol between "D" and "m"
is the pipe or "broken line" chr
I have an Archimedes now as well
as a BBC model "B", the Arc BASIC
is even more structured and much faster
*************have fun
wont guarantee answering, but you can try emailing me
if you have questions - or just post to the net
Regards,
Gavin Flower
--
The main "user" of well brought up, and educated, children is the community
at large. So if you really believe in "user pays", charge the correct users
- stop overloading parents with financial penalties.
******* These comments have no known correlation with dept. policy! *******