mutex: avoid wait queue lock if possible
This also tidies up the atomic operations a little and adds a new atom_cmp_xchg() as well as the same APIs for longs and pointers.main
parent
c66b05216d
commit
c36b03d97c
GPG Key ID:
EC22E476DC2D3D84
@ -0,0 +1,193 @@
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/* See the end of this file for copyright and license terms. */
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#pragma once
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#ifndef _ARCH_ATOM_H_
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#error "This file is not meant to be included directly, use <arch/atom.h>"
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#endif
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#include <gay/cdefs.h>
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#include <gay/types.h>
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#ifndef __LP64__
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#error "__LP64__ must be defined on amd64"
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#endif
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static inline long latom_read(const latom_t *latom)
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{
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return latom->_value;
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}
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static inline long latom_write(latom_t *latom, long val)
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{
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long rax;
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__asm__ volatile(
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" movq (%2), %0 \n" /* rax = atom->_value */
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"1: lock \n"
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" cmpxchgq %1, (%2) \n" /* if (latom->_value == rax) latom->_value = val */
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" pause \n" /* intel says you're supposed to do this in spin loops */
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" jne 1b \n" /* else goto 1 (rax updated to new latom->_value) */
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: "=a"(rax)
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: "r"(val), "r"(&latom->_value)
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: "cc", "memory"
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);
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return rax;
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}
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static inline long latom_cmp_xchg(latom_t *latom, long compare, long val)
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{
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long rax = compare;
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__asm__ volatile(
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" lock \n"
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" cmpxchlq %1, (%2) \n" /* if ((rax = latom->_value) == compare) latom->_value = val */
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: "+a"(rax)
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: "r"(val), "r"(&latom->_value)
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: "cc", "memory"
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);
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return rax;
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}
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/**
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* @brief Perform an atomic load/add/store.
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*
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* @param atom Atom to add to
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* @param val Value to add
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* @return The value of `atom` *before* the operation
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*/
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static inline long latom_add(latom_t *latom, long val)
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{
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__asm__ volatile(
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" lock \n"
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" xaddq %0, (%1) \n"
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: "+r"(val)
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: "r"(&latom->_value)
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: "cc", "memory"
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);
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return val;
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}
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static inline long latom_sub(latom_t *latom, long val)
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{
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return latom_add(latom, -val);
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}
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static inline bool latom_inc(latom_t *latom)
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{
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bool nonzero = false;
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__asm__ volatile(
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" lock \n"
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" incq (%1) \n"
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" setne %0 \n"
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: "+r"(nonzero) /* read+write to ensure the initial value isn't optimized out */
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: "r"(&latom->_value)
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: "cc", "memory"
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);
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return nonzero;
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}
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static inline bool latom_dec(latom_t *latom)
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{
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bool nonzero = false;
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__asm__ volatile(
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" lock \n"
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" decq (%1) \n"
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" setne %0 \n"
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: "+r"(nonzero) /* read+write to ensure the initializer isn't optimized out */
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: "r"(&latom->_value)
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: "cc", "memory"
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);
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return nonzero;
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}
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static inline long latom_and(latom_t *latom, long val)
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{
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long rax;
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__asm__ volatile(
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" movq (%2), %0 \n" /* rax = latom->_value */
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"1: andq %0, %1 \n" /* val &= rax */
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" lock \n"
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" cmpxchgq %1, (%2) \n" /* if (latom->_value == rax) latom->_value = val */
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" pause \n" /* intel says you're supposed to do this in spin loops */
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" jne 1b \n" /* else goto 1 (rax updated to new latom->_value) */
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: "=a"(rax), "+r"(val)
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: "r"(&latom->_value)
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: "cc", "memory"
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);
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return rax;
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}
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static inline long latom_or(latom_t *latom, long val)
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{
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long rax;
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__asm__ volatile(
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" movq (%2), %0 \n" /* rax = latom->_value */
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"1: orq %0, %1 \n" /* val |= rax */
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" lock \n"
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" cmpxchgq %1, (%2) \n" /* if (latom->_value == rax) latom->_value = val */
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" pause \n" /* intel says you're supposed to do this in spin loops */
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" jne 1b \n" /* else goto 1 (rax updated to new latom->_value) */
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: "=a"(rax), "+r"(val)
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: "r"(&latom->_value)
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: "cc", "memory"
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);
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return rax;
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}
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static inline long latom_xor(latom_t *latom, long val)
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{
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long rax;
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__asm__ volatile(
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" movq (%2), %0 \n" /* rax = latom->_value */
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"1: xorq %0, %1 \n" /* val ^= rax */
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" lock \n"
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" cmpxchgq %1, (%2) \n" /* if (latom->_value == rax) latom->_value = val */
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" pause \n" /* intel says you're supposed to do this in spin loops */
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" jne 1b \n" /* else goto 1 (rax updated to new latom->_value) */
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: "=a"(rax), "+r"(val)
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: "r"(&latom->_value)
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: "cc", "memory"
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);
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return rax;
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}
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static inline bool latom_set_bit(latom_t *latom, int pos)
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{
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int mask = 1 << pos;
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long oldval = latom_or(latom, mask);
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return (oldval & mask) == 0;
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}
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static inline bool latom_clr_bit(latom_t *latom, int pos)
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{
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int mask = 1 << pos;
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long oldval = latom_and(latom, ~mask);
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return (oldval & mask) != 0;
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}
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/*
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* This file is part of GayBSD.
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* Copyright (c) 2021 fef <owo@fef.moe>.
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*
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* GayBSD is nonviolent software: you may only use, redistribute, and/or
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* modify it under the terms of the Cooperative Nonviolent Public License
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* (CNPL) as found in the LICENSE file in the source code root directory
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* or at <https://git.pixie.town/thufie/npl-builder>; either version 7
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* of the license, or (at your option) any later version.
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*
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* GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
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* permitted by applicable law. See the CNPL for details.
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*/
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@ -0,0 +1,91 @@
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/* See the end of this file for copyright and license terms. */
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#pragma once
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#ifndef _ARCH_ATOM_H_
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#error "This file is not meant to be included directly, use <arch/atom.h>"
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#endif
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#include <gay/cdefs.h>
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#include <gay/types.h>
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/*
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* we use ILP32 on i386, long is the same as int
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*/
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#ifndef __ILP32__
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#error "__ILP32__ must be defined on i386"
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#endif
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static inline long latom_read(const latom_t *latom)
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{
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return latom->_value;
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}
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static __always_inline long latom_write(latom_t *latom, long val)
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{
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return atom_write((atom_t *)latom, val);
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}
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static __always_inline long latom_cmp_xchg(latom_t *latom, long compare, long val)
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{
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return atom_cmp_xchg((atom_t *)latom, compare, val);
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}
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static __always_inline long latom_add(latom_t *latom, long val)
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{
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return atom_add((atom_t *)latom, val);
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}
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static __always_inline long latom_sub(latom_t *latom, long val)
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{
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return atom_sub((atom_t *)latom, val);
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}
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static __always_inline bool latom_inc(latom_t *latom)
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{
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return atom_inc((atom_t *)latom);
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}
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static __always_inline bool latom_dec(latom_t *latom)
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{
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return atom_dec((atom_t *)latom);
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}
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static __always_inline long latom_and(latom_t *latom, long val)
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{
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return atom_and((atom_t *)latom, val);
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}
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static __always_inline long latom_or(latom_t *latom, long val)
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{
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return atom_or((atom_t *)latom, val);
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}
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static __always_inline long latom_xor(latom_t *latom, long val)
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{
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return atom_xor((atom_t *)latom, val);
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}
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static __always_inline bool latom_set_bit(latom_t *latom, int pos)
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{
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return atom_set_bit((atom_t *)latom, pos);
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}
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static __always_inline bool latom_clr_bit(latom_t *latom, int pos)
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{
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return atom_clr_bit((atom_t *)latom, pos);
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}
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/*
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* This file is part of GayBSD.
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* Copyright (c) 2021 fef <owo@fef.moe>.
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*
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* GayBSD is nonviolent software: you may only use, redistribute, and/or
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* modify it under the terms of the Cooperative Nonviolent Public License
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* (CNPL) as found in the LICENSE file in the source code root directory
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* or at <https://git.pixie.town/thufie/npl-builder>; either version 7
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* of the license, or (at your option) any later version.
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*
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* GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
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* permitted by applicable law. See the CNPL for details.
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*/
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@ -1,185 +0,0 @@
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/* See the end of this file for copyright and license terms. */
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#include <asm/common.h>
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/* int atom_read(const atom_t *atom) */
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ASM_ENTRY(atom_read)
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mov 4(%esp), %ecx
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mov (%ecx), %eax
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ret
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ASM_END(atom_read)
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/* int atom_write(atom_t *atom, int val) */
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ASM_ENTRY(atom_write)
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mov 4(%esp), %edx
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mov 8(%esp), %ecx
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mov (%edx), %eax
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1: lock
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cmpxchg %ecx, (%edx)
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pause
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jne 1b
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ret
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ASM_END(atom_write)
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/* bool atom_inc(atom_t *atom) */
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ASM_ENTRY(atom_inc)
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mov 4(%esp), %edx
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lock
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incl (%edx)
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xor %eax, %eax
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setne %al
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ret
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ASM_END(atom_inc)
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/* bool atom_dec(atom_t *atom) */
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ASM_ENTRY(atom_dec)
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mov 4(%esp), %edx
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lock
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decl (%edx)
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xor %eax, %eax
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setne %al
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ret
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ASM_END(atom_dec)
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/* int atom_add(atom_t *atom, int val) */
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ASM_ENTRY(atom_add)
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mov 4(%esp), %edx
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mov 8(%esp), %eax
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lock
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xadd %eax, (%edx)
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ret
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ASM_END(atom_add)
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/* int atom_sub(atom_t *atom, int val) */
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ASM_ENTRY(atom_sub)
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mov 4(%esp), %edx
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mov 8(%esp), %eax
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/* there is no xsubl, so we add the two's complement */
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neg %eax
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lock
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xadd %eax, (%edx)
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ret
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ASM_END(atom_sub)
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/* int atom_and(atom_t *atom, int val) */
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ASM_ENTRY(atom_and)
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mov 4(%esp), %edx
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mov (%edx), %eax
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1: mov %eax, %ecx
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and 8(%esp), %ecx
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lock
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cmpxchg %ecx, (%edx)
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pause
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jne 1b
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ret
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ASM_END(atom_and)
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/* int atom_or(atom_t *atom, int val) */
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ASM_ENTRY(atom_or)
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mov 4(%esp), %edx
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mov (%edx), %eax
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1: mov %eax, %ecx
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and 8(%esp), %ecx
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lock
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cmpxchg %ecx, (%edx)
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pause
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jne 1b
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ret
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ASM_END(atom_or)
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/* int atom_xor(atom_t *atom, int val) */
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ASM_ENTRY(atom_xor)
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mov 4(%esp), %edx
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mov (%edx), %eax
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1: mov %eax, %ecx
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xor 8(%esp), %ecx
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lock
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cmpxchg %ecx, (%edx)
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pause
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jne 1b
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ret
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ASM_END(atom_xor)
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/* bool atom_set_bit(atom_t *atom, int bit) */
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ASM_ENTRY(atom_set_bit)
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mov 4(%esp), %edx
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mov 8(%esp), %ecx
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push %ebx
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mov $1, %ebx
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shl %cl, %ebx
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mov (%edx), %eax
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1: mov %eax, %ecx
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or %ebx, %ecx
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lock
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cmpxchg %ecx, (%edx)
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pause
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jne 1b
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/* return true if bit was clear before */
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not %eax
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and %ebx, %eax
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shr %cl, %eax
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pop %ebx
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ret
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ASM_END(atom_set_bit)
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/* bool atom_clr_bit(atom_t *atom, int bit) */
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ASM_ENTRY(atom_clr_bit)
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mov 4(%esp), %edx
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mov 8(%esp), %ecx
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push %ebx
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mov $0xfffffffe, %ebx
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rol %cl, %ebx
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mov (%edx), %eax
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1: mov %eax, %ecx
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and %ebx, %ecx
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lock
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cmpxchg %ecx, (%edx)
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pause
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jne 1b
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/* return true if bit was set before */
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not %ebx
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and %ebx, %eax
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shr %cl, %eax
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pop %ebx
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ret
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ASM_END(atom_clr_bit)
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|
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/*
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* This file is part of GayBSD.
|
||||
* Copyright (c) 2021 fef <owo@fef.moe>.
|
||||
*
|
||||
* GayBSD is nonviolent software: you may only use, redistribute, and/or
|
||||
* modify it under the terms of the Cooperative Nonviolent Public License
|
||||
* (CNPL) as found in the LICENSE file in the source code root directory
|
||||
* or at <https://git.pixie.town/thufie/npl-builder>; either version 7
|
||||
* of the license, or (at your option) any later version.
|
||||
*
|
||||
* GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
|
||||
* permitted by applicable law. See the CNPL for details.
|
||||
*/
|
||||
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Reference in New Issue