CS520
Spring 2019
Laboratory 3
Friday February 8
The lab must be submitted prior to 12noon on Sunday February 10.

Do an initial implementation of the f2i function described in the Program 2 specification.

To test your function, you will need to supply a main function. Put this function in another file! In this main function you may use float types so that you can set up a test rigging to evaluate your function. In addition, you should use a union to change the interpretation of bytes in memory. For example, you might construct a main function like this one:

#include <stdio.h>
#include <stdint.h>
#include <inttypes.h>

int32_t f2i(uint32_t);

union {
  uint32_t i;
  float f;
} u;

int main(void)
{
  uint32_t in;
  int32_t i;

  in = 0x4D2AAAAA;
  u.i = in;
  i = u.f;
  printf("%08" PRIx32 " (%e) --> %08" PRIx32 " (my result is %08" PRIx32 ")\n",
    in, u.f, i, f2i(in));

  return 0;
}

If the main function is in the file main.c and your implementation of f2i is in the file prog2.c, then to compile and run the program:

gcc -Wall -std=c99 prog2.c main.c -o lab3
./lab3

This lab will be tested using only the following inputs to f2i:

• zeroes (16 points)
• infinities (16 points)
• NaNs (16 points)
• denormalized values (16 points)
• values with negative exponents (16 points)
• 0x4D2AAAAA (20 points)

You should submit all the source code for your lab in one file called prog2.c. Be sure this file does not include a main function!

To turn in this laboratory, type:

% ~cs520/bin/submit lab3 prog2.c

Submissions can be checked by typing:

% ~cs520/bin/scheck lab3

Remember that there are no late submissions of labs. Submit what you have prior to 12noon on Sunday February 10. Be careful: one minute late is late.

Comments and questions should be directed to pjh@cs.unh.edu