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	The leading blank lines are apparently an artefact of an older source control system. They are not required and they look like accidents, because starting a source file with a blank line is not a regular habit of software developers nowadays. This is a cherry-pick of commit 37cc20add8fb5b83bb5299a26cd3b41e0f776017 from branch 'libpng18'. Signed-off-by: John Bowler <jbowler@acm.org> Signed-off-by: Cosmin Truta <ctruta@gmail.com>
		
			
				
	
	
		
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			55 lines
		
	
	
		
			1.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* contrib/mips-msa/linux.c
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 *
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 * Copyright (c) 2020-2023 Cosmin Truta
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 * Copyright (c) 2016 Glenn Randers-Pehrson
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 * Written by Mandar Sahastrabuddhe, 2016.
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 * Updated by Sui Jingfeng, 2021.
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 *
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 * This code is released under the libpng license.
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 * For conditions of distribution and use, see the disclaimer
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 * and license in png.h
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 *
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 * On Linux, png_have_msa is implemented by reading the pseudo-file
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 * "/proc/self/auxv".
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 *
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 * See contrib/mips-msa/README before reporting bugs.
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 *
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 * STATUS: SUPPORTED
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 * BUG REPORTS: png-mng-implement@sourceforge.net
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 */
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#include <elf.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <unistd.h>
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static int
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png_have_msa(png_structp png_ptr)
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{
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   Elf64_auxv_t aux;
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   int fd;
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   int has_msa = 0;
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   fd = open("/proc/self/auxv", O_RDONLY);
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   if (fd >= 0)
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   {
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      while (read(fd, &aux, sizeof(Elf64_auxv_t)) == sizeof(Elf64_auxv_t))
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      {
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         if (aux.a_type == AT_HWCAP)
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         {
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            uint64_t hwcap = aux.a_un.a_val;
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            has_msa = (hwcap >> 1) & 1;
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            break;
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         }
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      }
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      close(fd);
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   }
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#ifdef PNG_WARNINGS_SUPPORTED
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   else
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      png_warning(png_ptr, "/proc/self/auxv open failed");
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#endif
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   return has_msa;
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}
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