mirror of https://github.com/proxmox/mirror_qemu
48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
/*
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* SPDX-License-Identifier: GPL-2.0-or-later
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* Compare-and-swap for 128-bit atomic operations, generic version.
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*
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* Copyright (C) 2018, 2023 Linaro, Ltd.
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*
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* See docs/devel/atomics.rst for discussion about the guarantees each
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* atomic primitive is meant to provide.
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*/
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#ifndef HOST_ATOMIC128_CAS_H
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#define HOST_ATOMIC128_CAS_H
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#if defined(CONFIG_ATOMIC128)
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static inline Int128 ATTRIBUTE_ATOMIC128_OPT
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atomic16_cmpxchg(Int128 *ptr, Int128 cmp, Int128 new)
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{
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__int128_t *ptr_align = __builtin_assume_aligned(ptr, 16);
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Int128Alias r, c, n;
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c.s = cmp;
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n.s = new;
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r.i = qatomic_cmpxchg__nocheck(ptr_align, c.i, n.i);
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return r.s;
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}
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# define HAVE_CMPXCHG128 1
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#elif defined(CONFIG_CMPXCHG128)
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static inline Int128 ATTRIBUTE_ATOMIC128_OPT
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atomic16_cmpxchg(Int128 *ptr, Int128 cmp, Int128 new)
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{
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Int128Aligned *ptr_align = __builtin_assume_aligned(ptr, 16);
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Int128Alias r, c, n;
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c.s = cmp;
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n.s = new;
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r.i = __sync_val_compare_and_swap_16(ptr_align, c.i, n.i);
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return r.s;
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}
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# define HAVE_CMPXCHG128 1
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#else
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/* Fallback definition that must be optimized away, or error. */
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Int128 QEMU_ERROR("unsupported atomic")
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atomic16_cmpxchg(Int128 *ptr, Int128 cmp, Int128 new);
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# define HAVE_CMPXCHG128 0
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#endif
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#endif /* HOST_ATOMIC128_CAS_H */
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