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calc.c
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float.c
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writeup.pdf
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//float.c
//Floating point lab
//Stephen Marz
//20 Oct 2017
/////////////////////////////////////////////////////////////////
//
// DO NOT MODIFY THIS FILE (float.c)
// Compile using: aarch64-linux-gnu-gcc -o float float.c float.S
//
/////////////////////////////////////////////////////////////////
#include <stdio.h>
//Write these functions in float.S
int GetSign(int val);
int GetExponent(int val);
int GetFraction(int val);
int GetNorm(int fraction);
int GetRaise2(int exponent);
int main(int argc, char *argv[])
{
int sign;
int fraction;
int exponent;
int norm;
int val;
float fval;
if (argc < 2) {
printf("Usage: %s <value>\n", argv[0]);
return -1;
}
sscanf(argv[1], "%f", &val);
sign = GetSign(val);
exponent = GetExponent(val);
fraction = GetFraction(val);
norm = GetNorm(fraction);
fval = *(float*)&norm *
(exponent < 0 ?
1.0f / GetRaise2(-exponent) :
GetRaise2(exponent)
) *
(sign == 1 ? -1 : 1);
printf("0x%08x : %c%.6le x 2^(%d) = %.6f (should be %.6f)\n",
val,
(sign == 1 ? '-' : '+'),
*(float*)&norm,
exponent,
fval,
*(float*)&val
);
return 0;
}