z80 timing... 6502 timing

From: Allison J Parent <allisonp_at_world.std.com>
Date: Sat Apr 17 14:32:41 1999

<b) unsupported OPCs in the 8085 ? Did I miss them ? I did 2 years of
<8085 development projects, and never heared of (also of course never
<used) - can you tell what they where alike ?

Yes, They are somewhat handy.

 08h DSB double subtract HL-BC->HL

 10h SHRL shift right HL Shift HL pair right, MSB is copied
                10001000:00000010 becomes 11000100:00000001

 18h RDEL Rotate DE right through carry, handy 16bit rotate.
         SLDE (intel used this neumonic)

 28h LRI h,D8 load relative pointer immediate
                The value of HL is added with the immediate placed
                in the DE pair.

 38h LRI SP,D8 similar to the previous, good for SP relative ops.
         
 D9h SHLX Store HL at DE an indexed 16bit store.

 EDh LHLX Load HL from where DE points. 16 bit indexed load.

This is from memory... so if there are errors let me know, I'll dig out
the docs. I do remember that NEC up to at least '85 actively supported
these as they were in the intel, OKI and AMD designs.

Allison
Received on Sat Apr 17 1999 - 14:32:41 BST