Copy Link
Add to Bookmark
Report
Commodore Trivia 29
-------Commodore Trivia Edition #29 Questions and Answers Preface--------
Not to leave you in the dark for too long, here are the trivia
answers to the previous edition of Commodore Trivia. I am posting the
answers at this time, and will post the scores and winners in a few
days. This time frame is set up to allow time for any discussions on the
correctness of these answers. By this time, the newest edition of
trivia has been posted. I encourage you to enter it.
This edition of trivia answers has been posted to the USENET newsgroups:
comp.sys.cbm, alt.folklore.computers, and comp.sys.amiga.advocacy. It
has also been posted to the FidoNET CBM Echo.
Feel free to use these trivia answers in newsletters, magazines, and other
publications (please see disclaimer). If you use the trivia, I would
appreciate knowing where it has ended up. If you intend to use this
information, please wait a few days after the posting date to allow for
major errors to be corrected.
Please mail any new questions for upcoming trivia (with answers) to my
address.
This edition and previous editions the trivia can be obtained from my
mailserver.
To: brain@mail.msen.com
Subject: MAILSERV
Body:
send trivia1
quit
This will retrieve the first edition of the trivia. Replace the
number with the edition you want.
**NEW** Interested persons can now subscribe to the Trivia Mailing
List. To add your name to the list, please mail a message:
To: brain@mail.msen.com
Subject: MAILSERV
Body:
subscribe trivia Firstname Lastname
help
quit
Each new edition of the trivia will be automatically mailed to you when
it is made available on the Internet.
I try to post the answers for the questions shortly after the monthly
contest has ended. However, I usually wait a few days for any errors
I may have made to be worked out before scoring the contest.
-------Commodore Trivia Edition #29 Questions and Answers (BEGIN)--------
This edition should be sub-titled "Programmer's Trivia".
Q $1C0) What are the two configurations for the LORAM, HIRAM, GAME, and EXROM
pins that will allow the use of a full 64kB of RAM in the C64?
A $1C0) There are actually 4 configurations, in two categories:
LORAM 0 0 (X means either 1 or 0)
HIRAM 0 0
GAME 1 X
EXROM X 0
Q $1C1) What is the first thing that the C64 (and VIC) KERNAL does upon
powerup?
A $1C1) The first thing each does is reset the stack pointer to $ff.
Q $1C2) What KERNAL routine is used to set a DOS channel to input?
A $1C2) CHKIN ($ffc6)
Q $1C3) What KERNAL routine is used to set a DOS channel to output?
A $1C3) CHKOUT ($ffc9)
Q $1C4) Before calling the routines in $1C2 and $1C3, what register must
you load?
A $1C4) You must load .X with the logical file number.
Q $1C5) What 3 devices can the KERNAL NOT load from?
A $1C5) keyboard (0), RS-232 (2), or screen (3). The first and last are
somewhat obvious, but allowing RS-232 loads would have made
loading from a remote machine possible. Incidentally, you can't
save to any of these devices, either.
Q $1C6) In the Commodore KERNAL, there are "high" and "low" level routines.
To which class of routines does "SECOND" belong?
A $1C6) low. It is used to specify the secondary address, as the '7' in
open 4,4,7.
Q $1C7) If a programmer calls the KERNAL routine "STOP" and the RUN/STOP
key is NOT pressed, what is returned in the .A register?
A $1C7) .A will contain a byte representing the last row of the keyboard
scan.
Q $1C8) The Commodore KERNAL routines are all accessed via a jump table.
What routine is used to change the values in the KERNAL jump table?
A $1C8) The appropriately named VECTOR ($ff8d) call, which few programmers
actually use.
Q $1C9) A call is made to a KERNAL routine, the call returns with the C
bit set and the .A register holds $02. What error does this
indicate?
A $1C9) "File already open"
Q $1CA) If a call to READST is made, and a $40 is returned in .A, what
does this indicate?
A $1CA) End of File.
Q $1CB) What routine can be called to determine the physical format of the
Commodore 64 screen in characters?
A $1CB) The also appropriately named SCREEN ($ffed) call.
Q $1CC) The Commodore 64 starts a non-destructive RAM test at what location?
A $1CC) $0300.
Q $1CD) Which way does the RAM test proceed: up or down?
A $1CD) up.
Q $1CE) Which KERNAL routine is used ONLY in conjunction with a Commodore
IEEE card?
A $1CE) SETTMO ($ffa2), which sets the IEEE bus card timeout flag. I infer
that Commodore thought many people would use the IEEE interface.
(Anyone know any more about this?)
Q $1CF) Many hybrid BASIC/ML programs use SYS to transfer control from BASIC
to ML. However, a few use USR(X). When using the latter function,
where does BASIC fetch the ML routine's starting address from?
A $1CF) 785 and 786, in classic LO:HI format.
The information in this between the lines marked by (BEGIN) and (END)
is copyright 1996 by Jim Brain. Provided that the information
between the (BEGIN) and (END) lines is not changed except to correct
typographical errors, the so marked copyrighted information may be
reproduced in its entirety on other networks or in other mediums. For
more information about using this file, please contact the address
shown below.
Jim Brain
j.brain@ieee.org
10710 Bruhn Avenue
Bennington, NE 68007
(402) 431-7754
--------Commodore Trivia Edition #29 Questions and Answers (END)---------
