Re: [Qemu-devel] Missing ARMv6 instructions?

[Jonas Maebe]

On 01 Apr 2006, at 22:51, Chris Wilson wrote:

> and they have been an extensive user of software patents,

And how:
  http://www.patent.gov.uk/patent/legal/summaries/2004/o29204.htm

"The invention in this case involves locating all of the input  
registers in one data storage area, and all of the output registers  
in another data storage area. Then the simulator only has to switch  
the two storage areas around (eg. by exchanging two pointer values)  
in order to effectively COPY all of the output registers to the  
corresponding input registers of the next stage in a single  
operation. The Hearing Officer concluded that this invention did  
involve a technical contribution — not simply because it produced a  
faster simulator, but because the fundamental construction of the  
simulator had been modified."


So yes, using

struct registers *a, *b;
a = b;

instead of

struct registers a, b;
memcpy(&a,&b,sizeof(b));

has been patented by ARM in the UK. In fact, wouldn't surprise me if  
Qemu violates this patent.


Jonas