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lavu/riscv: use Zbb CPOP/CPOPW at run-time

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Zbb static    Zbb dynamic   I baseline
popcount  1.336129286   3.469067758   20.146362909
popcountl 1.336322291   3.340292968   20.224829821
(seconds for 1 billion iterations on a SiFive-U74 core)

Signed-off-by: Paul B Mahol <onemda@gmail.com>
This commit is contained in:
Rémi Denis-Courmont 2024-06-08 12:02:27 +03:00 committed by Paul B Mahol
parent 934c2cd5fb
commit 47381f35a8
1 changed files with 69 additions and 4 deletions
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73
libavutil/riscv/intmath.h
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@ -1,4 +1,6 @@
/*
* Copyright © 2022-2024 Rémi Denis-Courmont.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
@ -23,6 +25,7 @@
#include "config.h"
#include "libavutil/attributes.h"
#include "libavutil/riscv/cpu.h"
/*
* The compiler is forced to sign-extend the result anyhow, so it is faster to
@ -70,12 +73,74 @@ static av_always_inline av_const int av_clip_intp2_rvi(int a, int p)
}
#if defined (__GNUC__) || defined (__clang__)
#define av_popcount __builtin_popcount
#if (__riscv_xlen >= 64)
#define av_popcount64 __builtin_popcountl
static inline av_const int av_popcount_rv(unsigned int x)
{
#if HAVE_RV && !defined(__riscv_zbb)
if (!__builtin_constant_p(x) &&
__builtin_expect(ff_rv_zbb_support(), true)) {
int y;
__asm__ (
".option push\n"
".option arch, +zbb\n"
#if __riscv_xlen >= 64
"cpopw %0, %1\n"
#else
#define av_popcount64 __builtin_popcountll
"cpop %0, %1\n"
#endif
".option pop" : "=r" (y) : "r" (x));
if (y > 32)
__builtin_unreachable();
return y;
}
#endif
return __builtin_popcount(x);
}
#define av_popcount av_popcount_rv
static inline av_const int av_popcount64_rv(uint64_t x)
{
#if HAVE_RV && !defined(__riscv_zbb) && __riscv_xlen >= 64
if (!__builtin_constant_p(x) &&
__builtin_expect(ff_rv_zbb_support(), true)) {
int y;
__asm__ (
".option push\n"
".option arch, +zbb\n"
"cpop %0, %1\n"
".option pop" : "=r" (y) : "r" (x));
if (y > 64)
__builtin_unreachable();
return y;
}
#endif
return __builtin_popcountl(x);
}
#define av_popcount64 av_popcount64_rv
static inline av_const int av_parity_rv(unsigned int x)
{
#if HAVE_RV && !defined(__riscv_zbb)
if (!__builtin_constant_p(x) &&
__builtin_expect(ff_rv_zbb_support(), true)) {
int y;
__asm__ (
".option push\n"
".option arch, +zbb\n"
#if __riscv_xlen >= 64
"cpopw %0, %1\n"
#else
"cpop %0, %1\n"
#endif
".option pop" : "=r" (y) : "r" (x));
return y & 1;
}
#endif
return __builtin_parity(x);
}
#define av_parity av_parity_rv
#endif
#endif /* AVUTIL_RISCV_INTMATH_H */