It is currently Sat Oct 21, 2017 4:19 pm

All times are UTC - 7 hours



Forum rules


Related:



Post new topic Reply to topic  [ 17 posts ]  Go to page Previous  1, 2
Author Message
 Post subject: Re: DSP Unmute
PostPosted: Wed Oct 19, 2016 8:31 pm 
Offline

Joined: Mon Mar 27, 2006 5:23 pm
Posts: 1338
Quote:
I seem to be one of the few here that prefers the "native" mnemonics


I'm well aware that changing the mnemonics for a CPU is highly controversial.

But I really felt this was a special exception: the SPC700 is absolutely, unequivocally, a shameless 6502 clone. Just like the HuC6280, it adds a few new instructions on top of it. Unlike the HuC, it also reorders the opcode bytes -- but nobody is writing code in db statements, so who cares?

The native mnemonics were almost certainly a thinly veiled attempt to avoid licensing fees for the use of the 6502 instruction set. And in this case, they are truly gross mnemonics that force you to think about parameter ordering (src,dest vs dest,src) and leave tons of holes that are not obvious until you get assembler errors for missing opcodes.

I've emulated ~15 processors now in higan, and the only other time I've made up mnemonics were when opcodes were not documented and I had zero choice (uPD96050 and Cx4). So this was not a decision I made lightly.

That said, I understand and respect if you do not care for this. Sorry to inflict it upon you ... perhaps someone could write a translator so people can work with whichever set they prefer :)


Top
 Profile  
 
 Post subject: Re: DSP Unmute
PostPosted: Wed Oct 19, 2016 9:57 pm 
Offline

Joined: Fri Jul 04, 2014 9:31 pm
Posts: 788
byuu wrote:
Unlike the HuC, it also reorders the opcode bytes -- but nobody is writing code in db statements, so who cares?

That's good to know. I've occasionally coded in db statements to get around bugs in the ancient version of WLA DX I've been using, and the only piece of real SPC700 code I've ever written is self-modifying... it hasn't been assembled or tested, but I'll get around to it someday...


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 17 posts ]  Go to page Previous  1, 2

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 8 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group