Unfortunately, it is common, and will remain so, that the Bit manipulations are not enabled at compilation time. This is an official policy for Debian ports in general (though they do not support RISC-V officially as of yet) to stick to the minimal target baseline, which does not include the B extension or even its Zbb subset. For inline helpers (CPOP, REV8), compiler builtins (CTZ, CLZ) or even plain C code (MIN, MAX, MINU, MAXU), run-time detection seems impractical. But at least it can work for the byte-swap DSP functions.
		
			
				
	
	
		
			82 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			82 lines
		
	
	
		
			2.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright © 2022 Rémi Denis-Courmont.
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "libavutil/cpu.h"
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#include "libavutil/cpu_internal.h"
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#include "libavutil/log.h"
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#include "config.h"
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#if HAVE_GETAUXVAL
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#include <sys/auxv.h>
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#define HWCAP_RV(letter) (1ul << ((letter) - 'A'))
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#endif
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int ff_get_cpu_flags_riscv(void)
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{
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    int ret = 0;
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#if HAVE_GETAUXVAL
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    const unsigned long hwcap = getauxval(AT_HWCAP);
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    if (hwcap & HWCAP_RV('I'))
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        ret |= AV_CPU_FLAG_RVI;
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    if (hwcap & HWCAP_RV('F'))
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        ret |= AV_CPU_FLAG_RVF;
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    if (hwcap & HWCAP_RV('D'))
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        ret |= AV_CPU_FLAG_RVD;
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    if (hwcap & HWCAP_RV('B'))
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        ret |= AV_CPU_FLAG_RVB_BASIC;
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    /* The V extension implies all Zve* functional subsets */
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    if (hwcap & HWCAP_RV('V'))
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        ret |= AV_CPU_FLAG_RVV_I32 | AV_CPU_FLAG_RVV_I64
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             | AV_CPU_FLAG_RVV_F32 | AV_CPU_FLAG_RVV_F64;
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#endif
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#ifdef __riscv_i
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    ret |= AV_CPU_FLAG_RVI;
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#endif
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#if defined (__riscv_flen) && (__riscv_flen >= 32)
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    ret |= AV_CPU_FLAG_RVF;
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#if (__riscv_flen >= 64)
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    ret |= AV_CPU_FLAG_RVD;
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#endif
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#endif
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#ifdef __riscv_zbb
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    ret |= AV_CPU_FLAG_RVB_BASIC;
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#endif
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    /* If RV-V is enabled statically at compile-time, check the details. */
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#ifdef __riscv_vectors
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    ret |= AV_CPU_FLAG_RVV_I32;
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#if __riscv_v_elen >= 64
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    ret |= AV_CPU_FLAG_RVV_I64;
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#endif
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#if __riscv_v_elen_fp >= 32
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    ret |= AV_CPU_FLAG_RVV_F32;
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#if __riscv_v_elen_fp >= 64
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    ret |= AV_CPU_FLAG_RVV_F64;
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#endif
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#endif
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#endif
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    return ret;
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}
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