PR #20873 opened by Rémi Denis-Courmont (Courmisch) URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20873 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20873.patch
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). From 3ea7c5449d2e35c01debdac8fb981675eb861644 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9mi=20Denis-Courmont?= <[email protected]> Date: Sun, 9 Nov 2025 15:01:03 +0200 Subject: [PATCH] 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). --- libavutil/riscv/cpu.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) 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) -- 2.49.1 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
