Consider the following objdump output showing the disassembly of a call instruct
ID: 3837055 • Letter: C
Question
Consider the following objdump output showing the disassembly of a call instruction to a function foo in an object code. 0000000000000000 : ... d: e8 00 00 00 00 call 12 e:R_x86_64_PC32 foo ... The linking with another object file contains foo produces an executable with the following code, where xx xx xx xx should be replaced by the offset relative to the address of the next instruction after the cell. 00000000004004f0 : ... 4004fd: e8 xx xx xx xx callq 40050c 400502: ... 000000000040050c : ... What is the value (in hexadecimal) of the four bytes xx xx xx xx as shown from left to right, starting at memory address 0x4004fe?Explanation / Answer
Suppose towards a contradiction that for same category C the language
LC isn't empty, it doesn't contain the descriptions of all mathematician machines,
and it's decidable. Then LC¯ is additionally not empty, not containing all mathematician
machines, and decidable.
Suppose that 6 C, otherwise apply the argument below to C¯ rather than
C.
Let Min be a machine specified hMini is in LC.
We will show that the Acceptance downside is decidable, and then we'll
reach a contradiction.
Given Associate in Nursing input (hMi, w) for the Acceptance downside, we tend to constract a brand new
Turing machine Mw that will the following: on input x, Mw 1st simulates
the behaviour of M on input w and
• If M on input w loops, then thus will Mw;
• If M on input w rejects, then thus will Mw;
• If M on input w accepts, then Mw continues with a simulation of Min
on input x.
In summary:
• If M accepts w, then Mw behaves like Min, Associate in Nursingd Mw accepts an input
x if and on condition that Min will. In alternative words, L(Mw) = L(Min) C and
so hMwi LC;
• if M doesn't settle for w, then Mw doesn't settle for any input, and
L(Mw) = 6 C, which suggests hMwi 6 LC.
We have verified that (hMi, w) A if and on condition that hMwi LC, and so A
would be decidable if LC were decidable. we've got reached a contradiction.