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/*
* SPDX-License-Identifier: GPL-2.0-or-later
* Atomic extract 64 from 128-bit, generic version.
*
* Copyright (C) 2023 Linaro, Ltd.
*/
#ifndef HOST_LOAD_EXTRACT_AL16_AL8_H
#define HOST_LOAD_EXTRACT_AL16_AL8_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 ATTRIBUTE_ATOMIC128_OPT
load_atom_extract_al16_or_al8(void *pv, int s)
{
uintptr_t pi = (uintptr_t)pv;
int o = pi & 7;
int shr = (HOST_BIG_ENDIAN ? 16 - s - o : o) * 8;
Int128 r;
pv = (void *)(pi & ~7);
if (pi & 8) {
uint64_t *p8 = __builtin_assume_aligned(pv, 16, 8);
uint64_t a = qatomic_read__nocheck(p8);
uint64_t b = qatomic_read__nocheck(p8 + 1);
if (HOST_BIG_ENDIAN) {
r = int128_make128(b, a);
} else {
r = int128_make128(a, b);
}
} else {
r = atomic16_read_ro(pv);
}
return int128_getlo(int128_urshift(r, shr));
}
#endif /* HOST_LOAD_EXTRACT_AL16_AL8_H */
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