20 Feb
2009
20 Feb
'09
5:29 p.m.
On 20 Feb 2009 at 18:59, Jim Leonard wrote:
I have never found a decent resource on NEC V20
special opcode
programming; the only stuff I've found has been on how to detect an NEC
through bugs, and searching via google has been unproductive for the
last 20 minutes. Is there a resource for what the extended instructions
were, or is that lost to paper history?
Dunno--my reference is "uPD70108/70116 Low-Power CMOS Microprocessors
User/s Manual" August 1985, Stock No. 500350. Sort of a strange read
if you're used to Intel terminology, as NEC uses their own. For
example, the register names are different (AW,BW,CW,DW,IX,IY; PS,
DS0, DS1, SS) and mnemoics are different--e.g., Intel AAM is called
CVTBD (convert bindary to decimal). Just enough difference to make
you think that NEC rewrote the Intel manual in Frisian.
There's also a V-Series general reference namual that describes all
of the members of the V-family, but not in any great detail.
Cheers,
Chuck