glibc/sysdeps/arm/arm-features.h

60 lines
2.5 KiB
C

/* Macros to test for CPU features on ARM. Generic ARM version.
Copyright (C) 2012-2024 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
#ifndef _ARM_ARM_FEATURES_H
#define _ARM_ARM_FEATURES_H 1
/* An OS-specific arm-features.h file should define ARM_HAVE_VFP to
an appropriate expression for testing at runtime whether the VFP
hardware is present. We'll then redefine it to a constant if we
know at compile time that we can assume VFP. */
#ifndef __SOFTFP__
/* The compiler is generating VFP instructions, so we're already
assuming the hardware exists. */
# undef ARM_HAVE_VFP
# define ARM_HAVE_VFP 1
#endif
/* An OS-specific arm-features.h file may define ARM_ASSUME_NO_IWMMXT
to indicate at compile time that iWMMXt hardware is never present
at runtime (or that we never care about its state) and so need not
be checked for. */
/* A more-specific arm-features.h file may define ARM_ALWAYS_BX to indicate
that instructions using pc as a destination register must never be used,
so a "bx" (or "blx") instruction is always required. */
/* The log2 of the minimum alignment required for an address that
is the target of a computed branch (i.e. a "bx" instruction).
A more-specific arm-features.h file may define this to set a more
stringent requirement.
Using this only makes sense for code in ARM mode (where instructions
always have a fixed size of four bytes), or for Thumb-mode code that is
specifically aligning all the related branch targets to match (since
Thumb instructions might be either two or four bytes). */
#ifndef ARM_BX_ALIGN_LOG2
# define ARM_BX_ALIGN_LOG2 2
#endif
/* An OS-specific arm-features.h file may define ARM_NO_INDEX_REGISTER to
indicate that the two-register addressing modes must never be used. */
#endif /* arm-features.h */