Path: utzoo!attcan!uunet!lll-winken!ames!pacbell!pbhye!bjskelly
From: bjskelly@pbhye.PacBell.COM (Bruce J. Skelly)
Newsgroups: comp.sys.cbm
Subject: Re: C128,C128D, and C128C??? Questions
Message-ID: <2355@pbhye.PacBell.COM>
Date: 23 Mar 89 02:23:54 GMT
References: <89Mar20.194245est.2737@godzilla.eecg.toronto.edu> <7606@killer.Dallas.TX.US>
Reply-To: bjskelly@pbhye.PacBell.COM (Bruce J. Skelly)
Organization: Pacific * Bell, San Ramon, CA
Lines: 45

In article <89Mar20.194245est.2737@godzilla.eecg.toronto.edu>, leblanc@eecg.toronto.edu (Marcel LeBlanc) says:
> 
> 2Mhz 6502 is (almost) 4 times faster than a 2Mhz Z80.  This is because
> memory (or IO) accesses on a Z80 take 3-4 cycles, whereas the same operation
> on a 6502 takes only one cycle (yes, the 6502 was an early RISC :-) ).  So
> even if you could get the Z80 to run flat out at 4MHz, it would still be
> only a little more than half the speed of the 8502 at 2MHz.  But then, I
> guess CP/M can use all the speed it can get...
>
I don't want to start a 'my cpu is better than your cpu' war here, after all
those of us with C128 have them both, but I have this benchmark report on
the Z80 cpu vs. the 6502 cpu published by Zilog in July of 1981.  They performed
10 tests:
	Computed GOTO Implementation
	8 X 8 Multiply Routine
	16 X 16 Multiply Routine
	Block Move
	Linear Search
	Insert into Linked List
	Bubble Sort
	Interrupt Handling
	Character String Translation
	Dynamic Memory Access

They included their program listings. Results were expressed as a ratio.

				6502/Z80
Number of Bytes of Code		2.63/1
Number of Lines of Source	3.05/1
Execution time of slowest	1.65/1*
Execution time of equal		1.32/1**

* Slowest means lowest speed version, which for the 6502 is 1.0 MHz with a
memory access time of 650ns., and 2.5 MHz and 575ns for the Z80.

** Equal means equivalent memory access time.  For the 6502B at 3.0 MHz that
was 170ns., while for the Z80B at 6.0Mhz it was 190ns.

Is there a trick involved here?  Could be.  More importantly, does anyone
care?  I'm sure that  those who love their 6502's will continue to love them,
and those that love there Z80's will go to bed with warm smiles on their
faces.

For those who distrust me it was publication #751-1955-0002 dated 6/12/81
Bruce