Date   : Thu, 02 Feb 2017 22:59:27 +0000
From   : jgh@... (J.G.Harston)
Subject: Pi-based second processor - fast, flexible,

Stephen Harris wrote:
>> How was the 274 MHz figure achieved and calculated ? I can't find
 >> any satisfactory explanation for it
> I believe it uses this code:
(...)

The program here:
http://mdfs.net/Software/BBCBasic/Testing/

It is calibrated to solely test the operation of the language CPU by 
executing a generalised sample of instructions on the language CPU, viz, 
the BASIC interpreter executing a specific set of BASIC code.

"274MHz" should only really be interpreted as "136 times faster than a 
hardware 6502 clocked at 2MHz", and the timing highlights the 
differences between implementations of the BASIC interpreter on 
different platforms. For instance, 65C12 BASIC is faster than 6502 BASIC 
doing trig/log because 65C12 BASIC is able to take advantage of (zp) 
addressing mode for a lot of the arithmetic instead of having to use eg 
LDY #0:LDA (zp),Y