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3a66b2b063
Bug 21047 reports that the clang assembler disallows the ARM implementations of _FPU_GETCW and _FPU_SETCW. These are deliberately written the way they are, using generic coprocessor instructions (from the days when VFP was just one possible coprocessor for ARM) that have the right encodings, to handle the case of the instructions being used runtime-conditionally inside glibc, where use of these macros is not meant to result in either the assembler requiring VFP to be enabled at assembly time or in it marking the object as using VFP. However, more recent ARM ARM versions have restricted the definitions of the coprocessor instructions and reportedly the clang assembler follows that in disallowing those names for VFP instructions. In the non-__SOFTFP__ case - which in fact is the only case where these macro definitions can be used outside the build of glibc itself - using VFP instruction names is of course fine, since we know that VFP is enabled for that compilation. Thus, this patch uses the current VFP names for these instructions in that case to improve compatibility for this header file. Tested for hard-float and soft-float builds of glibc, including that installed stripped shared libraries are unchanged by the patch. [BZ #21047] * sysdeps/arm/fpu_control.h [!__SOFTFP__] (_FPU_GETCW): Use VFP name for instruction. [!__SOFTFP__] (_FPU_SETCW): Likewise.
76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
/* FPU control word definitions. ARM VFP version.
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Copyright (C) 2004-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library 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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The GNU C Library 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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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library. If not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _FPU_CONTROL_H
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#define _FPU_CONTROL_H
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#if !(defined(_LIBC) && !defined(_LIBC_TEST)) && defined(__SOFTFP__)
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#define _FPU_RESERVED 0xffffffff
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#define _FPU_DEFAULT 0x00000000
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typedef unsigned int fpu_control_t;
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#define _FPU_GETCW(cw) (cw) = 0
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#define _FPU_SETCW(cw) (void) (cw)
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extern fpu_control_t __fpu_control;
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#else
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/* masking of interrupts */
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#define _FPU_MASK_IM 0x00000100 /* invalid operation */
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#define _FPU_MASK_ZM 0x00000200 /* divide by zero */
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#define _FPU_MASK_OM 0x00000400 /* overflow */
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#define _FPU_MASK_UM 0x00000800 /* underflow */
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#define _FPU_MASK_PM 0x00001000 /* inexact */
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#define _FPU_MASK_NZCV 0xf0000000 /* NZCV flags */
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#define _FPU_MASK_RM 0x00c00000 /* rounding mode */
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#define _FPU_MASK_EXCEPT 0x00001f1f /* all exception flags */
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/* Some bits in the FPSCR are not yet defined. They must be preserved when
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modifying the contents. */
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#define _FPU_RESERVED 0x00086060
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#define _FPU_DEFAULT 0x00000000
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/* Default + exceptions enabled. */
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#define _FPU_IEEE (_FPU_DEFAULT | 0x00001f00)
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/* Type of the control word. */
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typedef unsigned int fpu_control_t;
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/* Macros for accessing the hardware control word. */
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#ifdef __SOFTFP__
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/* This is fmrx %0, fpscr. */
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# define _FPU_GETCW(cw) \
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__asm__ __volatile__ ("mrc p10, 7, %0, cr1, cr0, 0" : "=r" (cw))
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/* This is fmxr fpscr, %0. */
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# define _FPU_SETCW(cw) \
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__asm__ __volatile__ ("mcr p10, 7, %0, cr1, cr0, 0" : : "r" (cw))
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#else
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# define _FPU_GETCW(cw) \
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__asm__ __volatile__ ("vmrs %0, fpscr" : "=r" (cw))
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# define _FPU_SETCW(cw) \
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__asm__ __volatile__ ("vmsr fpscr, %0" : : "r" (cw))
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#endif
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/* Default control word set at startup. */
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extern fpu_control_t __fpu_control;
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#endif /* __SOFTFP__ */
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#endif /* _FPU_CONTROL_H */
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