Date   : Thu, 23 Dec 1982 08:46:20 EST (Thu)
From   : Ben Goldfarb <goldfarb.ucf-cs@Udel-Relay>
Subject: Re: ZCPR?

ZCPR makes use of Z80 relative jumps, LDIR's, and some other assorted
Z80 instructions which won't execute on the 8085.  As soon as I
installed the Godbout dual processor in my system, I realized how much
I relied on ZCPR, so I hacked it to run on the 8085.

Since the program assembles under MAC, the authors used macros to
generate the Z80 opcodes.  I merely added a block move subroutine and
hacked the macros to generate 8085 instructions.  This results in an
increase in size primarily because of the tradeoff between two byte
JR's and three byte JMP's, so I had to eliminate some of the features,
namely JUMP and Go, plus optional hexadecimal constants.  I had never
used these features, so there wasn't any problem.

The big advantage of ZCPR, in my opinion, is that executable files can
reside in a "home" directory which will be searched no matter where you
are currently logged in (i.e., drive and user number).  Beyond that,
the expanded features are nice conveniences that replace some transient
utilities and make life with CP/M systems generally more enjoyable.

As I mentioned above, the hack is simple, but if anyone wants to save
the trouble of doing it themselves, I'd be glad to supply it to them if
they send me a self-addressed, stamped envelope, along with a disk.  If
you notify me by mail, I'll give you the address.  Alternatively,
someone could upload it to MC, but I can't FTP from here.

                               Ben Goldfarb
                               ARPA:  goldfarb.ucf-cs @ UDel-Relay
                               uucp:  ...!duke!ucf-cs!goldfarb