The UPT instruction would appear to be ideal for implementing search.
Unfortunately, although I found a mention to such a possible implementation in
a SHARE presentation, it was only very theoretical and because the UPT example
in the Principle of Operations is incomplete and I have not beein
The UPT (UPdate Tree) instruction inserts a new node in a tree
conditionally. If it does not find an existing node having a
nominated key in a [sub]tree, it inserts a new node into that
[sub]tree at a location that, while not inappropriate, can be
suboptimal.
It is thus useful for maintaining a
On 4/30/2013 11:37 PM, Anthony Rudd wrote:
The UPT instruction would appear to be ideal for implementing search.
Unfortunately, although I found a mention to such a possible implementation in
a SHARE presentation, it was only very theoretical and because the UPT example
in the Principle of
Sorting, yes indeed, conditional insertion is then the point; and when
the sort is not a utility but an internal one it can be designed to
work with UPT and its warts/characteristics/limitations.
The usefulness of UPT for search operations is more problematic, but
even for them something useful
On Wed, 1 May 2013 07:51:50 -0400, John Gilmore wrote:
The UPT (UPdate Tree) instruction inserts a new node in a tree
conditionally. If it does not find an existing node having a
nominated key in a [sub]tree, it inserts a new node into that
[sub]tree at a location that, while not inappropriate,
On 5/1/2013 7:41 AM, Paul Gilmartin wrote:
Ah! We need UPTG. And the corresponding search function. And
we need it to be serialized against concurrent updates (is it?)
UPT is a modal instruction. Thus, no grande form is needed. In 24- and
31-bit mode, nodes are eight bytes in length and
On 4/29/2013 10:10 PM, Paul Gilmartin wrote:
I don't know how it keeps a 128-bit PSW.
XSBOPSW16 DS XL16 16-BYTE PSW ANALOG OF RBOPSW
--
Edward E Jaffe
Phoenix Software International, Inc
831 Parkview Drive North
El Segundo, CA 90245
http://www.phoenixsoftware.com/
David Crayson is right to point out that a decent compiler would have
unrolled the loop in the specific five-element case he examines.
This is not, however, a tactic that is appropriate for n 5.
If one looks at what optimizing C compilers, the usual suspects, do
with the classical
In m38v41wbsc@garlic.com, on 04/29/2013
at 12:18 PM, Anne Lynn Wheeler l...@garlic.com said:
the claim has been made that 1/3rd of processor cycles for 370
instruction emulation went to checking for whether instruction
already fetched/decoded in the pipeline has been modified.
this
In
ofd1484f42.6be3b89a-on85257b5c.007e856a-85257b5c.007f3...@tsys.tss.net,
on 04/29/2013
at 07:09 PM, Kirk Talman rkueb...@tsys.com said:
I was given at one point the Assembler source of the fast Fourier
transform, which I wanted to port to the 360. I had to read the
94 PoOp several times
shmuel+...@patriot.net (Shmuel Metz , Seymour J.) writes:
It may be true for simulation of the S/370 on Intel, but a real
370/168 handled it in the I-unit.
re:
http://www.garlic.com/~lynn/2013f.html#65 Linear search vs. Binary search
high-end machines were horizontal microcode with lots
On Mon, 29 Apr 2013 10:50:25 -0400, John Gilmore wrote:
It is not at all a bad subroutine. In many contexts the form of the
second argument would be gratuitously clumsy, but this routine was
(almost certainly) intended to be called from COBOL, and eight '0' or
'1' characters is appropriate for
IBM Mainframe Discussion List IBM-MAIN@LISTSERV.UA.EDU wrote on
04/29/2013 11:06:34 AM:
From: Paul Gilmartin paulgboul...@aim.com
Has the z nowadays any memory protection mode that forbids fetching
instructions from data storage? (Many other processors have such.)
they have different
I would be surprised if a binary search could beat a linear search with
only five items in the list, which is the case in the example code
here. If usage of the function request codes were uniformly
distributed, the average number of list item comparisons with five items
for binary search
On 4/29/2013 1:56 PM, Ed Jaffe wrote:
My ROT has always been to prefer linear search for single-digit
quantities and prefer binary or hash algorithms for ten or more.
A long time ago I implemented Knuth's balanced tree algorithm (AoP Vol.
3, sect 6.2) as a generalized subroutine, and
I posted the formulæ for match-seeking binary and linear search in a
'related' thread.
Following Knuth, the standard figure of merit for match-seeking binary
search if the total number of ternary comparison operations required
to search a set with 2n + 1 argments. For the n keys k(1) k(2) .
.
On Mon, 29 Apr 2013 13:16:59 -0400, John Gilmore wrote:
The question which is faster depends in detail upon
1) whether binary search is implemented in assembly language, in which
case ternary comparison operations are available, or in a
statement-level language other that PL/I, in which case
The subroutine that was originally posted didn't modify itself, but it
constructed a
little subroutine (one instruction and branch for return) in a working
area which was
provided as a parameter by the caller. So there is no reentrant problem
and no
flushing of the I-cache.
Thank you for
IBM Mainframe Discussion List IBM-MAIN@LISTSERV.UA.EDU wrote on
04/29/2013 06:47:16 PM:
From: Bernd Oppolzer bernd.oppol...@t-online.de
Another story:
I once had a hard time to understand a (very old) assembler module. It
searched
strings in another string, and the string to look for was
On 30/04/2013 4:12 AM, Paul Gilmartin wrote:
On Mon, 29 Apr 2013 13:16:59 -0400, John Gilmore wrote:
The question which is faster depends in detail upon
1) whether binary search is implemented in assembly language, in which
case ternary comparison operations are available, or in a
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