1
0
mirror of https://github.com/FFmpeg/FFmpeg.git synced 2025-11-23 21:54:53 +02:00

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).
This commit is contained in:
Rémi Denis-Courmont
2025-11-09 15:01:03 +02:00
parent be99d2c0b2
commit 9b348aa60b

View File

@@ -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)