Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!microsoft!alonzo
From: alonzo@microsoft.UUCP (Alonzo GARIEPY)
Newsgroups: comp.sys.handhelds
Subject: Re: HP28 Emulator (Was: Re: (none) --- HP-28S Exponentiation)
Keywords: HP-28S ^ exponentiation power
Message-ID: <52051@microsoft.UUCP>
Date: 5 Mar 90 23:50:23 GMT
References: <364@images1.Waterloo.NCR.COM> <1090@tuvie> <1143@tuvie>
Reply-To: alonzo@microsoft.UUCP (Alonzo GARIEPY)
Organization: Microsoft Corp., Redmond WA
Lines: 22

In article <1143@tuvie> inst182@tuvie.UUCP (Inst.f.Techn.Informatik) writes:
> (I doubt that a CPU emulator would be as fast as the HP28 even on a 
> fast AT)...

You could build a Saturn emulator that would blow the socks off the 
HP28.  They call it a 1MHz machine, but that doesn't say much about 
the instruction timing.  Someone recently claimed that the 28 has a 
one bit memory bus, which I am inclined to believe.  At best, it has 
a 4 bit memory bus and a 4 bit register bus.  With a 16 bit 286 running 
at 16 MHz, you would have 64 times the speed.  That is easily enough 
to emulate the Saturn at several times the speed of the 28.

I have been thinking about doing this.  For one thing, it would greatly
ease the task of understanding how the hardware (interrupts, display, etc.)
works.  You are right about the copyright problems with the ROM, but you
could get into the same waters by duplicating the look and feel.  Since a
CPU doesn't have a look and feel, a Saturn emulator allows anyone who owns
a 28 to run the software on their PC by downloading the ROM.

I look forward to seeing your program.

alonzo