John McKown asked:
| Why do I need to know the number of 1 bits in
| each individual byte in a GPR? Is it _that_
| common a question in application or system
| code?
Say you were an operating system software developer.
Let's further say that you wanted to write a really
efficient cell
On Wed, Mar 11, 2015 at 10:49 AM, John McKown john.archie.mck...@gmail.com
wrote:
Given some of the new instructions, such as LGZR, I wish IBM would
publish a manual with a title like: What were the architects thinking
of? Explanation of the reasons behind the instructions in the z
On Wed, Mar 11, 2015 at 9:58 AM, Mike Shaw quick...@gmail.com wrote:
On Wed, Mar 11, 2015 at 10:49 AM, John McKown john.archie.mck...@gmail.com
wrote:
Given some of the new instructions, such as LGZR, I wish IBM would
publish a manual with a title like: What were the architects thinking
of?
I don't have any real understanding of this, but this is interesting:Every
serious hacker sooner or later needs the popcount instruction.
This population count instruction counts the set bits in a register, and is
so useful that the NSA demands that all computers they purchase implement it in
Pages 7 to 8 of this presentation:
https://share.confex.com/share/124/webprogram/Session16609.html
Evidently the code with SIMD instructions is the equivalent of what the
millicode does for SRST, but I may have misinterpreted what was said.
Using the millicoded instruction is evidently
On 2015-03-11, at 08:49, John McKown wrote:
And POPCNT is another
one. Why do I need to know the number of 1 bits in each individual
byte in a GPR?
Because CDC had it first? I suspect that it became a built-in
function in Pascal, CARD(), because Pascal was developed on a
CDC which had the
Pages 7 to 8 of this presentation:
https://share.confex.com/share/124/webprogram/Session16609.html
Evidently the code with SIMD instructions is the equivalent of what the
millicode does for SRST, but I may have misinterpreted what was said.
Using the millicoded instruction is evidently less
On 11 March 2015 at 16:41, Paul Gilmartin
0014e0e4a59b-dmarc-requ...@listserv.uga.edu wrote:
On 2015-03-11, at 08:49, John McKown wrote:
And POPCNT is another
one. Why do I need to know the number of 1 bits in each individual
byte in a GPR?
Because CDC had it first? I suspect
When Dan Greiner used to present new hardware instructions at SHARE, he used
to mention some had uses in micro/millicode. He talked about instructions he
had personally pushed for because he could see performance benefits by
using them in millicode. Those of us attending couldn't think
When Dan Greiner used to present new hardware instructions at SHARE, he
used to mention some had uses in micro/millicode. He talked about
instructions he had personally pushed for because he could see
performance benefits by using them in millicode. Those of us attending
couldn't think of
Oops. I dyslex'd the whole thing. Nevermind.
At 3/11/2015 04:06 AM, Binyamin Dissen wrote:
Easy alignment to a 256 byte boundary?
From: John McKown john.archie.mck...@gmail.com
Sent: Thursday, March 12, 2015 1:49 AM
Given some of the new instructions, such as LGZR, I wish IBM would
publish a manual with a title like: What were the architects thinking
of? Explanation of the reasons behind the instructions in the z
Given some of the new instructions, such as LGZR, I wish IBM would
publish a manual with a title like: What were the architects thinking
of? Explanation of the reasons behind the instructions in the z
architecture. Some are obvious, like L, ST, A. But why a single
instruction to do this? Is it
Oops. I dyslex'd the whole thing. Nevermind.
At 3/11/2015 04:06 AM, Binyamin Dissen wrote:
Easy alignment to a 256 byte boundary?
On Tue, 10 Mar 2015 18:57:53 -0400 David Cole dbc...@colesoft.com wrote:
:Per the new PoOps:
:
:
:LZRG R1,D2(X2,B2) [RXY-a]
:
:The second operand, with the
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