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- #pragma once
- #include <common/compiler.h>
- #include <arch/x86_64/asm/asm.h>
- /**
- * @brief 通过extern不存在的函数，来让编译器报错。以防止不符合要求的代码的产生。
- */
- extern void __cmpxchg_wrong_size(void) __compiletime_error("Bad argument size for cmpxchg");
- // 定义常量：操作符涉及到的字节数
- #define __X86_CASE_B 1
- #define __X86_CASE_W 2
- #define __X86_CASE_L 4
- #define __X86_CASE_Q 8
- /**
- * @brief lock cmpxchg指令的包装。
- * 将_ptr指向的值与old_ptr指向的值做比较，如果相等，则将_new指向的值，加载到_ptr指向的值中。
- */
- #define __raw_try_cmpxchg(_ptr, _old_ptr, _new, size) \
- ({ \
- bool is_success = false; \
- typeof(_ptr) _old = (typeof(_ptr))(_old_ptr); \
- typeof(*(_ptr)) __old = *_old; \
- typeof(*(_ptr)) __new = (_new); \
- switch (size) \
- { \
- case __X86_CASE_B: \
- { \
- volatile uint8_t *__ptr = (volatile uint8_t *)(_ptr); \
- asm volatile("lock cmpxchgb %[new], %[ptr]\n\t" \
- : CC_OUT(z)(is_success), \
- [ptr] "+m"(*__ptr), \
- [old] "+a"(__old) \
- : [new] "q"(__new) \
- : "memory"); \
- break; \
- } \
- case __X86_CASE_W: \
- { \
- volatile uint16_t *__ptr = (volatile uint16_t *)(_ptr); \
- asm volatile("lock cmpxchgw %[new], %[ptr]\n\t" \
- : CC_OUT(z)(is_success), \
- [ptr] "+m"(*__ptr), \
- [old] "+a"(__old) \
- : [new] "q"(__new) \
- : "memory"); \
- break; \
- } \
- case __X86_CASE_L: \
- { \
- volatile uint32_t *__ptr = (volatile uint32_t *)(_ptr); \
- asm volatile("lock cmpxchgl %[new], %[ptr]\n\t" \
- : CC_OUT(z)(is_success), \
- [ptr] "+m"(*__ptr), \
- [old] "+a"(__old) \
- : [new] "q"(__new) \
- : "memory"); \
- break; \
- } \
- case __X86_CASE_Q: \
- { \
- volatile uint64_t *__ptr = (volatile uint64_t *)(_ptr); \
- asm volatile("lock cmpxchgq %[new], %[ptr]\n\t" \
- : CC_OUT(z)(is_success), \
- [ptr] "+m"(*__ptr), \
- [old] "+a"(__old) \
- : [new] "q"(__new) \
- : "memory"); \
- break; \
- } \
- default: \
- __cmpxchg_wrong_size(); \
- } \
- if (unlikely(is_success == false)) \
- *_old = __old; \
- likely(is_success); \
- })
- #define arch_try_cmpxchg(ptr, old_ptr, new_ptr) \
- __raw_try_cmpxchg((ptr), (old_ptr), (new_ptr), sizeof(*ptr))
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