(1)
Consider the following self-contained program:
#include <stdio.h
int main() {
int endian, foo;
foo = 0;
endian = 0;
printf("hello world, from a %s-endian machine\n", endian ? "big" : "little");
return endian;
}
Figure out what should be used in the assignments to foo and endian (instead of the current initializations to zero) for the program to correctly describe the endian-ness of the machine it is running on. The assignment to foo should be a constant, and the assignment to endian should be an expression involving foo. No other variables or lines of code are needed. Your program should not assume anything about word size.
Write your answer like:
foo =
endian =
To get full credit you need to explain your reasoning in one or two sentences: why does this code work?
(2)
For each of the following, create C expressions involving a given int x that evaluate to 1 if and only if the condition is true, and 0 otherwise. A “nibble” is half a byte (4 bits). Follow the bit-level integer coding rules in section 2.1 of the textbook (and note errata: http://csapp.cs.cmu.edu/public/errata.html), with the additional restriction that you may not use equality (==) or inequality (!=) tests.
A. At least one bit of x is 0.
B. At least one bit of x is 1.
C. Any of the bits in the most significant nibble of x is 0.
D. Any of the bits in the least significant nibble of x is 1.
E. The most significant and the least significant byte are equal. For this part equality (==) testing is allowed. F. Any even bit of x is 1. The least-significant bit is an even bit, for example. For this part you can assume an int is 32-bits.
see https://classes.cs.uchicago.edu/current/15400-1/svn.html
