mras0 · HackerTrans

6 個月前discuss

There already exist cross-compilers (e.g. http://sun.hasenbraten.de/vbcc/ and various amiga-gcc versions). vAmos is more for the case where you want to use an Amiga-native compiler (say SAS/C http://pjhutchison.org/tutorial/sas_c.html) but work on Linux/Windows.

mras0

6 個月前discuss

Amiga Forever is a distribution of software (Amiga ROMs and OS disks) and a full system emulator: CPU, custom chips (graphics/sound/..) etc. It allows you to emulate various Amiga systems completely.

vAmos is just CPU and an embedded ROM/OS replacement that does just enough to run (some) AmigaOS command line programs. The primary use case is for cross-development (running Amiga compilers/tools, testing simple stuff, etc.) without having to boot a full system emulator for each command and better integration with e.g. host-side Makefiles.

With the vAmos=WINE analogy, Amiga Forever=VirtualBox/VMWare.

mras0

8 個月前discuss

Size optimizing assembly code finds use in a variety of places. Demoscene for size constrained things is one of them, but also "hacking"/exploits and of course "whitehat" stuff (patches / compiler optimization etc).

mras0

8 個月前discuss

I understand what you're getting at, but in this case even I (who know what most things on that page means) struggle to understand why it was submitted. Are we looking for the 0E opcode? New optimization opportunities?

Genuinely asking, for this post did you click on the link and say "yeah, I got the point" or did you involve an LLM? If you did, what did you ask it? I'm asking because I want to get better at LLM use (Another example post (and prompt) where you've used this, that's also fine)!

mras0

8 個月前discuss

The link is to an opcode map with strange abbreviations with no apparent explanation. Asking "What am I looking at?" without doing any research (with a LLM or otherwise) is entirely reasonable.

mras0

8 個月前discuss

Not sure why you're being downvoted. You need a to know quite a bit of esoteric knowledge to parse this beyond knowing x86 opcodes (even x86 assembly).

It's more or less the same information you get from the intel manuals (specifically appendix 2A of https://www.intel.com/content/www/us/en/developer/articles/t...). There you can also see what e.g. "Jb" means (a byte sized immediate following the instruction that specifies a sign-extended relative offset to the instruction).

One-byte opcodes here differs from 2 byte opcodes (386+ IIRC) prefixed by a 0F byte and even more convoluted stuff added later.

mras0

7 年前discuss

Because it's a standard pitfall: https://gcc.gnu.org/onlinedocs/cpp/Duplication-of-Side-Effec...

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