RE: Write System Pointer to User Space

Actually COPYBYTES is supposed to be the fastest. However, it does not copy
pointers.

-Bob Cozzi
www.RPGxTools.com
If everything is under control, you are going too slow.
- Mario Andretti


-----Original Message-----
From: mi400-bounces@xxxxxxxxxxxx [mailto:mi400-bounces@xxxxxxxxxxxx] On
Behalf Of Dave McKenzie
Sent: Monday, June 20, 2005 10:07 AM
To: MI Programming on the AS400 / iSeries
Subject: Re: [MI400] Write System Pointer to User Space

Looking an an MI pgm with a 32-byte CPYBLA and a 32-byte CPYBWP, the 
CPYBLA uses LSDX/STSDX (Load/Store string doubleword indexed), while 
CPYBWP uses 2 pairs of LQ/STQ (Load/Store quadword).

One could write test loops to find out which is faster.

I suspect memcpy always does CPYBWP.

--Dave

Steve Richter wrote:
> 
> -----Original Message-----
> From: mi400-bounces@xxxxxxxxxxxx [mailto:mi400-bounces@xxxxxxxxxxxx]On
> Behalf Of Dave McKenzie
> Sent: Sunday, June 19, 2005 2:11 PM
> To: MI Programming on the AS400 / iSeries
> Subject: Re: [MI400] Write System Pointer to User Space
> 
> 
> Hi Peter,
> 
>>Here's a pgm that does that.  The "memcpy" function does the equivalent
>>of a CPYBWP (Copy Bytes With Pointers) MI instruction under the covers.
> 
> I have always assumed that CPYBWP was slower than CPYBLA.  Not true? Does
memcpy always use CPYBWP in place of CPYBLA? ( I know,  LDQ and STQ! )
> 
> -Steve
>
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