Oldskooler Ramblings

the unlikely child born of the home computer wars

Archive for March 18th, 2007

GDC Highlights from a Sick, Sick Man

Posted by Trixter on March 18, 2007

(This post is a week late, but posts are usually better late than never.) I went to GDC the first week of March, and although I was incredibly sick the entire time and missed 90% of the conference, I did manage the following highlights which made it all worthwhile:

  • Finally met Mike Melanson, reverse-engineer virtuoso of video and audio codecs, because he lives in the area. Went to dinner with him and the local MobyGames crew (Flipkin, Ron, Tom Servo) and had great food in a great bar called The Chieftain. (Despite the name, it was an Irish/California-themed bar.)  I quickly lost my voice, but it was worth it.
  • GDC awards ceremony. Graeme Devine presented a community award to The Fat Man; Lord British awarded lifetime achievement to Miyamoto, who accepted in person; some Sam & Max jokes; great fun. Presented by Tim Schaefer who cracked jokes. Excellent vibe. That was the only time I saw Simon Carless (on stage) as he was too busy to meet with anyone during the event. Our MobyGames intern rushed Miyamoto and shook his hand as he got off stage. Whore :-)
  • Later that night, we went to a bar looking for food and I quite literally bumped into The Fat Man by accident and we talked for 10 minutes. He loves Moby; I love his music; it was something I always wish I could have done and now I have. That guy deserves more work.
  • Thursday I met Chris Hargrove (Kiwidog / Hornet) and some other sceners. Chris was this chance thing — I literally screamed to him from the booth when I recognized him. Hadn’t seen him since he crashed at my place a decade ago. We talked about why Duke Nukem Forever has been delayed for so long; caught up on other stuff; he gave me the skinny on what finally happened to Tran. Nice catch-up.
  • Thursday went to the programmer’s challenge and got a few right (to myself — the gameshow was for the super-talented panel) .  Some questions/answers were played for laughs. Some scary smart people on that panel…
  • Friday participated in a game preservation roundtable sponsored by IGDA and am now a member of the group (!).
  • Met Jeff Roberts of Rad Game Tools and expressed my appreciation of his Smacker video codec, a low-resource codec used in hundreds if not thousands of DOS games. Always wanted to do that.

Sick, sick, and more sick, had three fevers, just now this week getting over it. Because of fever I was in the hotel room half the time, only saw Miyamoto at the awards and missed his keynote. I also had to leave Friday afternoon and missed the demoscene party that Pyro throws every year after the event… Still, I’ll never forget it and am glad I went.

Posted in Demoscene, Gaming | 5 Comments »

Oldskooler is wrong!

Posted by Trixter on March 18, 2007

In my last post, I stated that interrupts were supposed to be disabled on an 8088 for a MOV to the stack segment register (SS). Turns out that interrupts are supposed to be disabled during ALL segment register moves, not just SS! That explains why the procedure works to test if you have a buggy CPU or not:

Start DEBUG and run the following commands:

-A 100

All registers are displayed at this point, where you want to look at the value in the AX register. If it is “0000” your 8088 CPU has the bug. AX = “0001” means your CPU passes the test & does not have the bug.

Why does this work? The T(race) command tries to single-step the MOV ES,AX instruction, but on a working cpu, the trace will include the INC AX as well, before the cpu stops so that you can check the result (value in AX). You can just as easily check the IP value, i.e. the position of the next opcode to be executed: If this is INC AX then you have a buggy cpu.

Many thanks to the venerable Terje Mathisen and DJ Delorie for cluing me in.

Posted in Programming | 1 Comment »