[FFmpeg-cvslog] [ffmpeg] branch master updated. 9b348aa60b riscv/cpu: add V subset feature detection

[ffmpeg-git--- via ffmpeg-cvslog]

The branch, master has been updated
       via  9b348aa60b0f1b45a6cfbae5451bf1544fc6fd93 (commit)
      from  be99d2c0b214ec2ff5ec492668ccec5469ca45ad (commit)


- Log -----------------------------------------------------------------
commit 9b348aa60b0f1b45a6cfbae5451bf1544fc6fd93
Author:     Rémi Denis-Courmont <r...@remlab.net>
AuthorDate: Sun Nov 9 15:01:03 2025 +0200
Commit:     Rémi Denis-Courmont <r...@remlab.net>
CommitDate: Tue Nov 11 18:40:47 2025 +0000

    riscv/cpu: add V subset feature detection
    
    This adds support for detecting Zve32x, Zve32f, Zve64x and Zve64d on
    a system that does not support (or declare) the full V feature set.
    
    Because the code assumes that vector detected at runtime are at least
    128-bit long, we have to manually check that too (in theory, vectors
    can be 32-bit or 64-bit, though that makes little sense in 2025).

diff --git a/libavutil/riscv/cpu.c b/libavutil/riscv/cpu.c
index 379703651a..8cc91625c7 100644
--- a/libavutil/riscv/cpu.c
+++ b/libavutil/riscv/cpu.c
@@ -22,6 +22,7 @@
 # define _GNU_SOURCE
 #endif
 #include "libavutil/cpu.h"
+#include "libavutil/riscv/cpu.h"
 #include "libavutil/cpu_internal.h"
 #include "libavutil/macros.h"
 #include "libavutil/log.h"
@@ -64,6 +65,21 @@ int ff_get_cpu_flags_riscv(void)
         if (pairs[1].value & RISCV_HWPROBE_IMA_V)
             ret |= AV_CPU_FLAG_RVV_I32 | AV_CPU_FLAG_RVV_I64
                  | AV_CPU_FLAG_RVV_F32 | AV_CPU_FLAG_RVV_F64;
+#ifdef RISCV_HWPROBE_EXT_ZVE32X
+        else if ((pairs[1].value & RISCV_HWPROBE_EXT_ZVE32X) &&
+                 ff_get_rv_vlenb() >= 16) { // runtime detect assumes 128+ bits
+            ret |= AV_CPU_FLAG_RVV_I32;
+
+            if (pairs[1].value & RISCV_HWPROBE_EXT_ZVE32F)
+                ret |= AV_CPU_FLAG_RVV_F32;
+            if (pairs[1].value & RISCV_HWPROBE_EXT_ZVE64X) {
+                ret |= AV_CPU_FLAG_RVV_I64;
+
+                if (pairs[1].value & RISCV_HWPROBE_EXT_ZVE64D)
+                    ret |= AV_CPU_FLAG_RVV_F64;
+            }
+        }
+#endif
 #endif
 #ifdef RISCV_HWPROBE_EXT_ZBB
         if (pairs[1].value & RISCV_HWPROBE_EXT_ZBB)

-----------------------------------------------------------------------

Summary of changes:
 libavutil/riscv/cpu.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)


hooks/post-receive
-- 


_______________________________________________
ffmpeg-cvslog mailing list -- ffmpeg-cvslog@ffmpeg.org
To unsubscribe send an email to ffmpeg-cvslog-le...@ffmpeg.org