22 Dec
2001
22 Dec
'01
11:02 p.m.
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(a)jetnet.ab.ca>
To: classiccmp(a)classiccmp.org <classiccmp(a)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.