hw 10

CS-UY 2214 — Homework 10 Jeff Epstein Introduction Unless otherwise specified, put your answers in a plain text file named hw10.txt . Number each answer. Submit your work on Gradescope. The slides, available on Brightspace, cover many useful Intel opcodes. You may consult the online Intel assembly language reference to help you understand any unknown opcodes. You can also use the offcial Intel developer’s manual. To aid in debugging your assembly language programs, you can use gdb or similar. Please read the “Reversing tutorial,” available on Brightspace. Problems 1. Consider a hypothetical computer architecture with a hypothetical assembly language. It has 32-bit registers (named r0, r1, etc) and 32-bit pointers. Its memory consists of 8-bit cells. It has (at least) the following instructions: • lw addr , reg – read a 32-bit value from memory address addr and store it in the named register • sw addr , reg – store the 32-bit value in the register into memory address addr • mov reg , imm – store the immediate value into the register Consider the following code written in this assembly language: mov r3, 0x19fab0c0 sw 0x200, r3 ; write the value in r3 to address 200 lw 0x200, r5 ; and read it from 200, into register r5 sw 0x202, r3 ; note! we write to address 202, not 200 lw 0x200, r4 ; read the 32-bit value at address 200, into r4 Answer the following questions about the value of registers after the above program executes. Give each answer as a single 32-bit number in hex. If the answer cannot be determined from the data given, state why. (a) What value would you expect to find in register r5, if this is a big-endian architecture? Explain your answer. (b) What value would you expect to find in register r5, if this is a little-endian architecture? Explain your answer. (c) What value would you expect to find in register r4, if this is a big-endian architecture? Explain your answer. (d) What value would you expect to find in register r4, if this is a little-endian architecture? Explain your answer. 1