From: Segher Boessenkool <segher@kernel•crashing.org>
To: Thomas Huth <thuth@redhat•com>
Cc: slof@lists•ozlabs.org, nikunj@linux•vnet.ibm.com, aik@ozlabs•ru,
linuxppc-dev@lists•ozlabs.org, gkurz@linux•vnet.ibm.com
Subject: Re: [SLOF PATCH 1/2] fbuffer: Improve invert-region helper
Date: Tue, 28 Jul 2015 12:04:16 -0500 [thread overview]
Message-ID: <20150728170416.GB28839@gate.crashing.org> (raw)
In-Reply-To: <1438078795-14360-2-git-send-email-thuth@redhat.com>
On Tue, Jul 28, 2015 at 12:19:54PM +0200, Thomas Huth wrote:
> : invert-region ( addr len -- )
> - 0 ?DO dup dup rb@ -1 xor swap rb! 1+ LOOP drop
> -;
> -
> -: invert-region-x ( addr len -- )
> - /x / 0 ?DO dup dup rx@ -1 xor swap rx! xa1+ LOOP drop
> + 2dup or 7 and CASE
> + 0 OF 3 rshift 0 ?DO dup dup rx@ -1 xor swap rx! xa1+ LOOP ENDOF
> + 2 OF 1 rshift 0 ?DO dup dup rw@ -1 xor swap rw! wa1+ LOOP ENDOF
> + 4 OF 2 rshift 0 ?DO dup dup rl@ -1 xor swap rl! la1+ LOOP ENDOF
> + 6 OF 1 rshift 0 ?DO dup dup rw@ -1 xor swap rw! wa1+ LOOP ENDOF
> + dup OF 0 ?DO dup dup rb@ -1 xor swap rb! 1+ LOOP ENDOF
> + ENDCASE
> + drop
> ;
Can you access device memory as 64 bits for all supported devices?
You can get a bigger speedup by writing some of the core blitting
functions in C, btw.
A small simplification:
2dup or 7 and CASE
0 OF 3 rshift 0 ?DO dup dup rx@ -1 xor swap rx! xa1+ LOOP ENDOF
4 OF 2 rshift 0 ?DO dup dup rl@ -1 xor swap rl! la1+ LOOP ENDOF
3 and
2 OF 1 rshift 0 ?DO dup dup rw@ -1 xor swap rw! wa1+ LOOP ENDOF
dup OF 0 ?DO dup dup rb@ -1 xor swap rb! 1+ LOOP ENDOF
ENDCASE
If this code is often called unaligned, it makes more sense to special-
case the begin and end probably.
Segher
next prev parent reply other threads:[~2015-07-28 17:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-28 10:19 [SLOF PATCH 0/2] fbuffer: Improve the speed of the cursor drawing Thomas Huth
2015-07-28 10:19 ` [SLOF PATCH 1/2] fbuffer: Improve invert-region helper Thomas Huth
2015-07-28 17:04 ` Segher Boessenkool [this message]
2015-07-28 21:00 ` Thomas Huth
2015-07-28 10:19 ` [SLOF PATCH 2/2] fbuffer: Use a smaller cursor Thomas Huth
2015-07-29 3:05 ` Alexey Kardashevskiy
2015-07-29 3:42 ` [SLOF] " Segher Boessenkool
2015-07-29 6:03 ` Thomas Huth
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