同步异常、External abort、Serror、prefetch abort、data abort的区别

1、同步异常和异步异常的概念

具备以下3个行为的称之为同步异常：
• The exception is generated as a result of direct execution or attempted execution of an instruction.
• The return address presented to the exception handler is guaranteed to indicate the instruction that caused the exception.
• The exception is precise

其实就是说：

• 异常是由执行或尝试执行指令产生的
• 产生异常的那个位置是确定的，即每次执行到“那个指令处”就会产生
• 异常是precise的

具备以下3个行为的称之为异步异常：：
• The exception is not generated as a result of direct execution or attempted execution of the instruction stream.
• The return address presented to the exception handler is not guaranteed to indicate the instruction that caused the exception.
• The exception is imprecise.