mirror of https://github.com/xemu-project/xemu.git
41 lines
1.1 KiB
C
41 lines
1.1 KiB
C
/*
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* SPDX-License-Identifier: GPL-2.0-or-later
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* Atomic extract 64 from 128-bit, AArch64 version.
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*
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* Copyright (C) 2023 Linaro, Ltd.
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*/
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#ifndef AARCH64_LOAD_EXTRACT_AL16_AL8_H
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#define AARCH64_LOAD_EXTRACT_AL16_AL8_H
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#include "host/cpuinfo.h"
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#include "tcg/debug-assert.h"
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/**
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* load_atom_extract_al16_or_al8:
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* @pv: host address
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* @s: object size in bytes, @s <= 8.
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*
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* Load @s bytes from @pv, when pv % s != 0. If [p, p+s-1] does not
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* cross an 16-byte boundary then the access must be 16-byte atomic,
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* otherwise the access must be 8-byte atomic.
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*/
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static inline uint64_t load_atom_extract_al16_or_al8(void *pv, int s)
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{
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uintptr_t pi = (uintptr_t)pv;
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__int128_t *ptr_align = (__int128_t *)(pi & ~7);
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int shr = (pi & 7) * 8;
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uint64_t l, h;
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/*
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* With FEAT_LSE2, LDP is single-copy atomic if 16-byte aligned
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* and single-copy atomic on the parts if 8-byte aligned.
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* All we need do is align the pointer mod 8.
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*/
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tcg_debug_assert(HAVE_ATOMIC128_RO);
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asm("ldp %0, %1, %2" : "=r"(l), "=r"(h) : "m"(*ptr_align));
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return (l >> shr) | (h << (-shr & 63));
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}
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#endif /* AARCH64_LOAD_EXTRACT_AL16_AL8_H */
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