This function is similar to pthread_cond_wait, except that the third argument is the absolute time value until which the reader thread is willing to wait before it gives up.
The only byte-oriented arithmetic function on the SPU is absdb, "absolute difference of bytes," which gives the absolute value of the difference between two operands.
SPU 上惟一一个面向字节的计算函数是 absdb(意思是 “absolute difference of bytes”),计算两个操作数间的差的绝对值。