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accel/tcg: Add aarch64 lse2 load_atom_extract_al16_or_al8 

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-05-24 22:43:52 +00:00
parent a8bde8da47
commit 129fe7cddb
1 changed files with 40 additions and 0 deletions
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40
host/include/aarch64/host/load-extract-al16-al8.h Normal file
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/*
* SPDX-License-Identifier: GPL-2.0-or-later
* Atomic extract 64 from 128-bit, AArch64 version.
*
* Copyright (C) 2023 Linaro, Ltd.
*/
#ifndef AARCH64_LOAD_EXTRACT_AL16_AL8_H
#define AARCH64_LOAD_EXTRACT_AL16_AL8_H
#include "host/cpuinfo.h"
#include "tcg/debug-assert.h"
/**
* load_atom_extract_al16_or_al8:
* @pv: host address
* @s: object size in bytes, @s <= 8.
*
* Load @s bytes from @pv, when pv % s != 0. If [p, p+s-1] does not
* cross an 16-byte boundary then the access must be 16-byte atomic,
* otherwise the access must be 8-byte atomic.
*/
static inline uint64_t load_atom_extract_al16_or_al8(void *pv, int s)
{
uintptr_t pi = (uintptr_t)pv;
__int128_t *ptr_align = (__int128_t *)(pi & ~7);
int shr = (pi & 7) * 8;
uint64_t l, h;
/*
* With FEAT_LSE2, LDP is single-copy atomic if 16-byte aligned
* and single-copy atomic on the parts if 8-byte aligned.
* All we need do is align the pointer mod 8.
*/
tcg_debug_assert(HAVE_ATOMIC128_RO);
asm("ldp %0, %1, %2" : "=r"(l), "=r"(h) : "m"(*ptr_align));
return (l >> shr) | (h << (-shr & 63));
}
#endif /* AARCH64_LOAD_EXTRACT_AL16_AL8_H */