1 /* Macros to test for CPU features on ARM. Generic ARM version. 2 Copyright (C) 2012-2022 Free Software Foundation, Inc. 3 This file is part of the GNU C Library. 4 5 The GNU C Library is free software; you can redistribute it and/or 6 modify it under the terms of the GNU Lesser General Public 7 License as published by the Free Software Foundation; either 8 version 2.1 of the License, or (at your option) any later version. 9 10 The GNU C Library is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 13 Lesser General Public License for more details. 14 15 You should have received a copy of the GNU Lesser General Public 16 License along with the GNU C Library. If not, see 17 <https://www.gnu.org/licenses/>. */ 18 19 #ifndef _ARM_ARM_FEATURES_H 20 #define _ARM_ARM_FEATURES_H 1 21 22 /* An OS-specific arm-features.h file should define ARM_HAVE_VFP to 23 an appropriate expression for testing at runtime whether the VFP 24 hardware is present. We'll then redefine it to a constant if we 25 know at compile time that we can assume VFP. */ 26 27 #ifndef __SOFTFP__ 28 /* The compiler is generating VFP instructions, so we're already 29 assuming the hardware exists. */ 30 # undef ARM_HAVE_VFP 31 # define ARM_HAVE_VFP 1 32 #endif 33 34 /* An OS-specific arm-features.h file may define ARM_ASSUME_NO_IWMMXT 35 to indicate at compile time that iWMMXt hardware is never present 36 at runtime (or that we never care about its state) and so need not 37 be checked for. */ 38 39 /* A more-specific arm-features.h file may define ARM_ALWAYS_BX to indicate 40 that instructions using pc as a destination register must never be used, 41 so a "bx" (or "blx") instruction is always required. */ 42 43 /* The log2 of the minimum alignment required for an address that 44 is the target of a computed branch (i.e. a "bx" instruction). 45 A more-specific arm-features.h file may define this to set a more 46 stringent requirement. 47 48 Using this only makes sense for code in ARM mode (where instructions 49 always have a fixed size of four bytes), or for Thumb-mode code that is 50 specifically aligning all the related branch targets to match (since 51 Thumb instructions might be either two or four bytes). */ 52 #ifndef ARM_BX_ALIGN_LOG2 53 # define ARM_BX_ALIGN_LOG2 2 54 #endif 55 56 /* An OS-specific arm-features.h file may define ARM_NO_INDEX_REGISTER to 57 indicate that the two-register addressing modes must never be used. */ 58 59 #endif /* arm-features.h */ 60