Viewing profile — gp2000

Well, I was pessimistic. Just pushed an update that slightly more than doubles the execution speed with a PR to the main depot pending. It is very close to 20 times faster than the…

Though it'll still be kinda slow on a Model I, I've written an about 9 times faster Z-80 code for the network evaluation. I imagine the pull request will end up in the main depot b…

I first heard of this in humorist Dave Barry's column. His description is worth a read. https://www.theexplodingwhale.com/evidence/resources/dave-ba...

And on github. I imagine it is the same as the Internet Archive copy but I have not checked. https://github.com/historicalsource/asteroids

It is in the sense that Radio Shack put TRS-80 as a brand on all of their computers up until the mid eighties when they started to move into PC clones. Xroar emulates the Color Com…

The version for the Model 3 runs on stock hardware as it shipped in 1980. It has a interrupt that fires every second vblank. Thus it is possible to get in sync with the beam but to…

It really was a term of derision. Sure, some may have used it affectionately and even more might do so now, but by and large it wasn't used in kindness. To cite a reference, the fi…

That isn't a bug. In the original if a guess contains a repeated letter and there is only one occurrence of that letter in the target work then the first (on the left) letter will …

I imagine you're recalling this folklore.org posting: https://www.folklore.org/StoryView.py?story=Make_a_Mess,_Cle...

And it could also save time. The Z-80 conditional return takes 5 cycles (or "T-States" in Zilog terminology) to execute if the condition is not met and 11 cycles otherwise. Quite w…

The Z-80 stack pointer (SP) is a full 16 bit register. The stack can be anywhere in memory and be as large as needed. The 6502 has only an 8 bit stack pointer which points into pag…

Perhaps this Vintage Space episode is video you were thinking about: https://www.youtube.com/watch?v=r5g9AglBmSI

The Z-80 came out in 1976, three years before the 68000 and was an extension of the 8080. I don't see comparing the two as fair or sensible.

Yes, enjoyable and good ideas. I feel like I've been on that "project" before. You do a bunch of work, dig into things and then discover a simple answer that, in hindsight, could h…

Although it is a historical (and disavowed) footnote, the Open Text Index launched in April 1995 and sported full text indexing of web pages -- more than 6 months before Alta Vista…

You can request the documents and go photocopy them yourself at the museum. Or have their researchers do it for a fee. Just don't bother with these as they've already been done: ht…

The original arcade Mortal Kombat (and MK2, MK3 and UMK3) were all written in assembly for the TMS34010 processor. No doubt ports of it to the Sega Genesis did use 68K assembler. T…

The bug is explained by Dave Theurer himself in this video: https://www.youtube.com/watch?v=41TbGi7u598&t=168 Like many games at the time the code in the ROMs had tamper protection…

I imagine the original labels would have been in English. The assembly source code I've seen for Japanese games has variables and labels in English with Japanese comments in Shift-…

This hybrid approach was used for a series of arcade games on XArcade for the Xbox 360. Frogger, Gauntlet, Joust, Gyruss and a bunch of others. I think we referred to it as "reskin…

Do you have a more direct link? That one just goes to Noah's home page and for the life of me I couldn't navigate to the ultra-fast math page nor find it via Google. Edit: I think …

Yes, for better or worse ugly is definitely a 2nd-order predictor of success. I guess "ugly" is a fair assessment of the 8086 at the time. Certainly the 68000 was a much cleaner an…

You could choose that the memory accesses be at any bit size from 1 to 32 with both unsigned and sign-extended register loads. In fact, I think you got to pick two sizes and for mo…

Emulation of that processor was a bit of a challenge. Fortunately the fully general bit addressibility was only used in gzip decompression and the drawing instructions (circles, re…

In command contexts "." refers to the current line (e.g., :.,$s/a/b/ will perform the a -> b substitution from the current line to the last line of the file). That comes from ex wh…