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ae9c6a9ded
Unlike Clang, GCC does not support 8-byte atomics on i686 with the -mno-80387 flag set, so until that is fixed, implement a minimal set of atomics that are currently required.
62 lines
1.9 KiB
C++
62 lines
1.9 KiB
C++
/*
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* Copyright (c) 2022, Idan Horowitz <idan.horowitz@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Types.h>
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extern "C" {
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#if defined(__GNUC__) && !defined(__clang__) // FIXME: Remove this file once GCC supports 8-byte atomics on i686
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u64 kernel__atomic_compare_exchange_8(u64 volatile*, u64*, u64, int, int);
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# pragma redefine_extname kernel__atomic_compare_exchange_8 __atomic_compare_exchange_8
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u64 kernel__atomic_compare_exchange_8(u64 volatile* memory, u64* expected, u64 desired, int, int)
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{
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u64 previous;
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asm volatile("lock; cmpxchg8b %1"
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: "=A"(previous), "+m"(*memory)
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: "b"((u32)desired), "c"((u32)(desired >> 32)), "0"(*expected));
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return previous;
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}
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u64 kernel__atomic_load_8(u64 volatile*, int);
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# pragma redefine_extname kernel__atomic_load_8 __atomic_load_8
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u64 kernel__atomic_load_8(u64 volatile* memory, int)
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{
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u64 previous;
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asm volatile("movl %%ebx, %%eax\n"
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"movl %%ecx, %%edx\n"
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"lock; cmpxchg8b %1"
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: "=A"(previous), "+m"(*memory));
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return previous;
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}
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void kernel__atomic_store_8(u64 volatile*, u64, int);
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# pragma redefine_extname kernel__atomic_store_8 __atomic_store_8
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void kernel__atomic_store_8(u64 volatile* memory, u64 value, int)
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{
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u64 expected = *memory;
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asm volatile("1: lock; cmpxchg8b %0\n"
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" jne 1b"
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: "=m"(*memory)
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: "b"((u32)value), "c"((u32)(value >> 32)), "A"(expected));
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}
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u64 kernel__atomic_fetch_add_8(u64 volatile*, u64, int);
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# pragma redefine_extname kernel__atomic_fetch_add_8 __atomic_fetch_add_8
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u64 kernel__atomic_fetch_add_8(u64 volatile* memory, u64 value, int memory_order)
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{
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u64 previous = *memory;
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while (kernel__atomic_compare_exchange_8(memory, &previous, previous + value, memory_order, memory_order) != previous)
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;
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return previous;
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}
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#endif
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}
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