From j.brain@ieee.org Thu Oct 10 11:16:05 EET DST 1996 Article: 60218 of comp.sys.cbm Path: news.cs.tut.fi!news.funet.fi!news.ramk.fi!news.csc.fi!news.eunet.fi!EU.net!howland.erols.net!news.mathworks.com!uunet!in3.uu.net!pravda.aa.msen.com!conch.aa.msen.com!not-for-mail From: j.brain@ieee.org (Jim Brain) Newsgroups: comp.sys.cbm,alt.folklore.computers,comp.sys.amiga.advocacy Subject: Commodore Trivia Edition #29 Answers Date: 8 Oct 1996 20:13:01 -0400 Organization: Brain Innovations, Inc. Lines: 173 Sender: brain@msen.com Message-ID: NNTP-Posting-Host: conch.aa.msen.com X-Newsreader: Yarn 0.90 with YES 0.22 X-URL: http://www.msen.com/~brain/ Xref: news.cs.tut.fi comp.sys.cbm:60218 alt.folklore.computers:154208 comp.sys.amiga.advocacy:173002 Getting out of the hole: -------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)--------- -- Jim Brain, Embedded System Designer, Brain Innovations, Inc. (BII)(offline sig) j.brain@ieee.org "Above views DO reflect my employer, since I'm my employer" Dabbling in WWW, Embedded Systems, VR, Old CBM computers, and Good Times! -Me- Jim Brain: BII, VR, and CBM info