装配内在的位测试和设置（BTS） [英] assembly intrinsic for bit test and set (BTS)

问题描述

结构节点*地址; //格式＆LT;地址，flagBit1，flagBit2＆GT;

我想用BTS为原子设置 flagBit1 位。

I want to use BTS to atomically set the flagBit1 bit.

修改

我要盲目设置该位，但不关心，如果它是previously设置或不

我可以使用汇编code得到这个工作作为<建议href=\"http://stackoverflow.com/questions/1983303/using-bts-assembly-instruction-with-gcc-compiler\">Using用gcc编译BTS汇编指令

I can use assembly code to get this done as suggested in Using bts assembly instruction with gcc compiler

但有一个内在的我可以用它在不同的架构移植？

But is there an intrinsic I can use which is portable across different architectures?

例如， GCC原子内建命令有 __ sync_fetch_and_or 。这是否具有相同的属性作为BTS？

For instance, gcc Atomic Builtins has __sync_fetch_and_or. Does this have the same property as BTS?

推荐答案

有关有点盲目设置， sync_fetch_and_or 或 sync_or_and_fetch 似乎都同样好，其结果丢弃编译器知道以优化它。
在x86上GCC不会用 BTS ，相反，它只会做一个锁或这应该是罚款。

For a blind setting of a bit, sync_fetch_and_or or sync_or_and_fetch seem to be both equally good, with the result discarded the compiler knows to optimize it out. On x86 gcc won't use bts, instead it will simply do a lock or which should be fine.

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