af844a1149
Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
/*
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* SPDX-License-Identifier: GPL-2.0-or-later
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* Atomic extract 64 from 128-bit, generic version.
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*
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* Copyright (C) 2023 Linaro, Ltd.
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*/
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#ifndef HOST_LOAD_EXTRACT_AL16_AL8_H
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#define HOST_LOAD_EXTRACT_AL16_AL8_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 ATTRIBUTE_ATOMIC128_OPT
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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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int o = pi & 7;
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int shr = (HOST_BIG_ENDIAN ? 16 - s - o : o) * 8;
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Int128 r;
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pv = (void *)(pi & ~7);
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if (pi & 8) {
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uint64_t *p8 = __builtin_assume_aligned(pv, 16, 8);
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uint64_t a = qatomic_read__nocheck(p8);
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uint64_t b = qatomic_read__nocheck(p8 + 1);
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if (HOST_BIG_ENDIAN) {
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r = int128_make128(b, a);
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} else {
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r = int128_make128(a, b);
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}
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} else {
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r = atomic16_read_ro(pv);
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}
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return int128_getlo(int128_urshift(r, shr));
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}
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#endif /* HOST_LOAD_EXTRACT_AL16_AL8_H */
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