Assume the two register writes in the write-back stage for popq occur in the order listed in Figure 4.20.What would be the effect of executing popq %rsp? Does this conform to the desired behavior for Y86-64, as determined in Problem 4.8?

Problem 4.8

The following assembly-code function lets us determine the behavior of the instruction popq %rsp for x86-64:

We find this function always returns 0xabcd. What does this imply about the behavior of popq %rsp? What other Y86-64 instruction would have the exact same behavior?

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1 2 3 5 6 7 8 text .globl poptest poptest: movq pushq popa movq movg ret %rap, %rdi $0xabcd %rsp %rap. %rax %rdi. %rsp Save stack pointer Push test value Pop to stack pointer Set popped value as return value Restore stack pointer