gcc/config/arm/linux-gas.h

/* Definitions of target machine for GNU compiler.
   ARM Linux-based GNU systems version.
   Copyright (C) 1997-2020 Free Software Foundation, Inc.
   Contributed by Russell King  <rmk92@ecs.soton.ac.uk>.

   This file is part of GCC.

   GCC is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published
   by the Free Software Foundation; either version 3, or (at your
   option) any later version.

   GCC is distributed in the hope that it will be useful, but WITHOUT
   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
   License for more details.

   Under Section 7 of GPL version 3, you are granted additional
   permissions described in the GCC Runtime Library Exception, version
   3.1, as published by the Free Software Foundation.

   You should have received a copy of the GNU General Public License and
   a copy of the GCC Runtime Library Exception along with this program;
   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
   <http://www.gnu.org/licenses/>.  */

/* This is how we tell the assembler that a symbol is weak.
   GAS always supports weak symbols.  */

/* Unsigned chars produces much better code than signed.  */
#define DEFAULT_SIGNED_CHAR 0

#undef  SUBTARGET_CPP_SPEC
#define SUBTARGET_CPP_SPEC  "%{posix:-D_POSIX_SOURCE} %{pthread:-D_REENTRANT}"

#undef  SIZE_TYPE
#define SIZE_TYPE "unsigned int"

#undef  PTRDIFF_TYPE
#define PTRDIFF_TYPE "int"

/* Use the AAPCS type for wchar_t, or the previous Linux default for
   non-AAPCS.  */
#undef WCHAR_TYPE
#define WCHAR_TYPE (TARGET_AAPCS_BASED ? "unsigned int" : "long int")

#undef  WCHAR_TYPE_SIZE
#define WCHAR_TYPE_SIZE BITS_PER_WORD

/* Clear the instruction cache from `beg' to `end'.  This makes an
   inline system call to SYS_cacheflush.  */
#define CLEAR_INSN_CACHE(BEG, END)					\
{									\
  register unsigned long _beg __asm ("a1") = (unsigned long) (BEG);	\
  register unsigned long _end __asm ("a2") = (unsigned long) (END);	\
  register unsigned long _flg __asm ("a3") = 0;				\
  __asm __volatile ("swi 0x9f0002		@ sys_cacheflush"	\
		    : "=r" (_beg)					\
		    : "0" (_beg), "r" (_end), "r" (_flg));		\
}