Date   : Wed, 20 Jul 1994 01:08:58 +0100 (BST)
From   : clr1@...
Subject: My 6502 now dead fast!

My 6502 emulator now runs the 256^3 loop in 37.4 seconds on my dx/40. 
This is a pretty substantial increase on my previous results (and pretty 
good compared to the other emulators in progress). This is mostly due to 
hard-coded jumps to and from instructions (no calls and rets) and some 
various things I've added. The jumps were Stuart Anderson's idea (he's 
pretty quiet on the mailing list but I'm in touch with him via phone 
too!) but the other bits were mine. My bits didn't speed up the 256^3 
loop that much but they should speed up the emulator for more complex 
instructions. I also have had a couple of other ideas but they won't 
speed up the 256^3 loop so I can't be bothered doing them at the moment. 
The final version of my 6502 should also be about 5% faster due to a 
system of instruction calling that I'm going to use (but it's too fiddly 
to try under Turbo Pacsal).

I now have the OS loaded in okay and I've started going through it but 
it's pretty hard without a hard-copy of it disassembled. Does NOBODY have 
a BBC disassembler? Surely I'm not going to have to write one for one 
application...

Thanks to everyone (well, James) who replied to my questions posting - 
I'm working on them. I think I might be able to use some more PC flags in 
this case too...

+-------------------+-------------------------------------------------+
| /-- |_| /-- | (~  | "And the driving is like the driving of Jehu,   |
| \-- | | |   | _)  | the son of Nimshi, for he drives furiously."    |
+-------------------+-------------------- Second Book of Kings 9 v20 -+