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[FFmpeg-devel] x86inc: Add REPX macro to repeat instructions/operations

Message ID 20230929113622.122769-1-post@frankplowman.com
State Accepted
Commit ed8ddf0bd3b188a08ae0b4e21235f7e3e6ce501b
Headers show
Series [FFmpeg-devel] x86inc: Add REPX macro to repeat instructions/operations | expand

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Commit Message

Frank Plowman Sept. 29, 2023, 11:36 a.m. UTC 
From: Henrik Gramner <henrik@gramner.com>

When operating on large blocks of data it's common to repeatedly use
an instruction on multiple registers. Using the REPX macro makes it
easy to quickly write dense code to achieve this without having to
explicitly duplicate the same instruction over and over.

For example,

    REPX {paddw x, m4}, m0, m1, m2, m3
    REPX {mova [r0+16*x], m5}, 0, 1, 2, 3

will expand to

    paddw       m0, m4
    paddw       m1, m4
    paddw       m2, m4
    paddw       m3, m4
    mova [r0+16*0], m5
    mova [r0+16*1], m5
    mova [r0+16*2], m5
    mova [r0+16*3], m5

Commit taken from x264:
https://code.videolan.org/videolan/x264/-/commit/6d10612ab0007f8f60dd2399182efd696da3ffe4

Signed-off-by: Frank Plowman <post@frankplowman.com>
---
 libavutil/x86/x86inc.asm | 10 ++++++++++
 1 file changed, 10 insertions(+)

Comments

Henrik Gramner Oct. 1, 2023, 5:55 p.m. UTC | #1 
On Fri, Sep 29, 2023 at 1:38 PM Frank Plowman <post@frankplowman.com> wrote:
>  libavutil/x86/x86inc.asm | 10 ++++++++++
>  1 file changed, 10 insertions(+)

LGTM.

As a side note https://code.videolan.org/videolan/x86inc.asm is the
upstream repo for x86inc.asm.
Anton Khirnov Nov. 8, 2023, 12:52 p.m. UTC | #2 
Quoting Henrik Gramner via ffmpeg-devel (2023-10-01 19:55:57)
> On Fri, Sep 29, 2023 at 1:38 PM Frank Plowman <post@frankplowman.com> wrote:
> >  libavutil/x86/x86inc.asm | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> 
> LGTM.

pushed
diff mbox series

Patch

diff --git a/libavutil/x86/x86inc.asm b/libavutil/x86/x86inc.asm
index 251ee797de..e099ee4b10 100644
--- a/libavutil/x86/x86inc.asm
+++ b/libavutil/x86/x86inc.asm
@@ -232,6 +232,16 @@  DECLARE_REG_TMP_SIZE 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14
     %define gprsize 4
 %endif
 
+; Repeats an instruction/operation for multiple arguments.
+; Example usage: "REPX {psrlw x, 8}, m0, m1, m2, m3"
+%macro REPX 2-* ; operation, args
+    %xdefine %%f(x) %1
+    %rep %0 - 1
+        %rotate 1
+        %%f(%1)
+    %endrep
+%endmacro
+
 %macro PUSH 1
     push %1
     %ifidn rstk, rsp