当你仔细查看Intel指令手册时，你会看到Intel对PUSH指令的解释第一话就是：“Decrements the stack pointer and then stores the source operand on the top of the stack.”
我想你肯定知道“then”这个词的意思吧？
POP同理：
“Loads the value from the top of the stack to the location specified with the destination
operand (or explicit opcode) and then increments the stack pointer.”
