I read that Zilog Z-80 is assembler compatible but not binary compatible with Intel 8080. The new CPU have the same number and type of registers and ALU. Is there any core project on OpenCores with "Assembler Compatible, but not binary compatible" with major CPU architectures, such as x86, ARM, MIPS, etc? If not, is it possible to start a new project? Thank you. _____________________________________________________________ = You want FREE web-based email ? = You want your own @qon.lao.net address?? = Then you want LaoNet's WebMail ! = Get it at http://webmail.lao.net !!

At 11:05 PM 9/23/2007, big one wrote:


In fact the Z80 was a superset of the 8080 instructions set and as
such it was binary compatible. I have seen more than one instance
where the same binary object code would run on both CPU's.




There have been several MIPS devices in this class, but I have never
seen an x86 or ARM compatible. When OpenRisc1000 was first announced
back in 2000 ARM were very quick to warn that people should not try
to clone its instruction set. MIPS has taken legal action against
some commercial IP houses selling MIPS work-alikes. The x86 is the
subject of many closely held patents and I am not sure what fate
would await an open-IP version of it, but I don't think it would be pretty.


Regards,
John

"big one" wrote on Sun, 23 Sep 2007 20:05:16 -0700



The Z80 was binary compatible with the 8080 (but with many new
instructions). Unfortunately, Intel had copyrighted its set of mnemonics
so the Zilog guys had to create a different set for their own assembler.
This turned out to be much nicer than Intel's.

It was lucky that software patents were not possible back then and even
copyright for binary code (instead of source code) was still being
debated or the story might have been very different.

One case where a processor had the same assembler but different binary
codes was the 6809. Since this was compatible with Motorola's own 6800
there was no danger of any legal trouble (contrast that with the pin
compatible 6501 from MOS Technology). The 8086 was mostly compatible
with the 8008 at the assembly level, but since both were from Intel
there were no problems here either.



The assembler of our times is C, so I don't see the value of such a
project.

-- Jecel

I am curious why you would not want binary compatible? The main reason why CPUs in the past would be be assembler compatible but not binary compatible ware to handle new features in the CPU but still allow easy porting of existing software. There are several core projects on opencores with working versions of MIPS, and also Sparc, plus several major 8 and 16 bit architectures, and the Microblaze. I don't think there is a working open version of x86 or ARM. -----Original Message----- From: cores-bounces at opencores.org [mailto:cores-bounces at opencores.org] On Behalf Of big one Sent: Sunday, September 23, 2007 11:05 PM To: cores at opencores.org Subject: [oc] Assembler Compatible But Not Binary Compatible I read that Zilog Z-80 is assembler compatible but not binary compatible with Intel 8080. The new CPU have the same number and type of registers and ALU. Is there any core project on OpenCores with "Assembler Compatible, but not binary compatible" with major CPU architectures, such as x86, ARM, MIPS, etc? If not, is it possible to start a new project? Thank you. _____________________________________________________________ = You want FREE web-based email ? = You want your own @qon.lao.net address?? = Then you want LaoNet's WebMail ! = Get it at http://webmail.lao.net !! _______________________________________________ http://www.opencores.org/mailman/listinfo/cores