64位原子操作add

64位原子操作的加法的实现。只有看汇编才能理解.

64位的数据比较和交换EDX:EAX和ECX:EBX

1100306:80b5ef20 <atomic64_inc_return_cx8>:
1100307-80b5ef20:       53                      push   %ebx
1100308-80b5ef21:       89 d8                   mov    %ebx,%eax
1100309-80b5ef23:       89 ca                   mov    %ecx,%edx
1100310-80b5ef25:       f0 0f c7 0e             lock cmpxchg8b (%esi)
1100311-80b5ef29:       89 c3                   mov    %eax,%ebx
1100312-80b5ef2b:       89 d1                   mov    %edx,%ecx
1100313-80b5ef2d:       83 c3 01                add    $0x1,%ebx
1100314-80b5ef30:       83 d1 00                adc    $0x0,%ecx
1100315-80b5ef33:       f0 0f c7 0e             lock cmpxchg8b (%esi)
1100316-80b5ef37:       75 f0                   jne    80b5ef29 <atomic64_inc_return_cx8+0x9>
1100317-80b5ef39:       89 d8                   mov    %ebx,%eax
1100318-80b5ef3b:       89 ca                   mov    %ecx,%edx
1100319-80b5ef3d:       5b                      pop    %ebx
1100320-80b5ef3e:       c3                      ret
1100321-80b5ef3f:       90                      nop