6502/Z80 speed comparison (was MITS 2SIO serial chip?)

From: ajp166 <ajp166_at_bellatlantic.net>
Date: Sun Dec 23 07:02:32 2001

The most common reason for not using an hll is that unless the compiler
is well written and optimizing you see the compiler not the cpu.

Small C was a good language but the result was often so poor that
even a small amount of hand optimization was easy to accomplish.
For a cpu like 6502, this tended to be more true as many of the
things the C language likes just dont map to cpu instruction set
that directly. Same was true for most of the Z80 versions of
small C as most treated it as an 8080 and didnt use the more
useful instrucitons.

As tot he PDP-11 that was the consumate C machine at the
instruction set level.

Allison

-----Original Message-----
From: Ben Franchuk <bfranchuk_at_jetnet.ab.ca>
To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
Date: Saturday, December 22, 2001 9:40 PM
Subject: Re: 6502/Z80 speed comparison (was MITS 2SIO serial chip?)


>Richard Erlacher wrote:
>>
>> Let's leave compilers out of the equation. Even the same small-C
compiler,
>> targeted at the two quite different CPU's potentially represent a
significant
>> skew in favor of one or another of the two.
>>
>> Dick
>How can you have skew? That is the whole idea of benchmark is to
>compare
>two machines. I would expect that the simple C that was given would be a
>good test
>when judged with other benchmarks. The 8080/Z80/8086 all generate the
>same poor
>code. This surprised me as shows how poor the 16 bit intel product was.
>The PDP-11
>version was rather nice but it even has a few quirks.
>--
>Ben Franchuk --- Pre-historic Cpu's --
>www.jetnet.ab.ca/users/bfranchuk/index.html
>PS. Note all my FPGA machines generate nice 'Small C' code and have a
>resonably orthogonal instruction set. The well hacked Small C compiler
>self compiles under
>24 KB. A similar compiler for the 8080 is about 48KB.
Received on Sun Dec 23 2001 - 07:02:32 GMT