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@shahril96
Last active Apr 18, 2022
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Floating Point to IEEE 754 32-bit Converter
// Floating Point to IEEE 754 32-bit Converter
// this was written when i'm started to learn C
// code look suck, well, this shit is from 2 years ago :) (ahh unforgotten memories)
// hope you can learn somethings from this code
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdbool.h> // to use bool (c99 standard)
struct mantissa_s
{
double actual;
bool sign;
char exponent;
bool denormalized;
int mantissa_bit;
};
struct standardNum
{
double num;
int exponent;
};
// function prototype
void getNormalizeValue(double num, struct standardNum *sN);
void getBitfrom32BitFloating(double num, struct mantissa_s *mantissa);
char *num2BinCharStr(int dNum, int representNum);
int main()
{
double set_ur_number_here = -99.99;
struct mantissa_s mantissa_struct;
getBitfrom32BitFloating(set_ur_number_here, &mantissa_struct);
char *exponentBit = num2BinCharStr(mantissa_struct.exponent, 8);
char *mantissaBit = num2BinCharStr(mantissa_struct.mantissa_bit, 23);
printf("\nActual Number \t: %.32f\n", mantissa_struct.actual);
printf("Sign \t\t: %d (%s value)\n", mantissa_struct.sign, mantissa_struct.sign ? "Negative" : "Positive");
printf("Exponent \t: %s\n", exponentBit);
printf("Type \t\t: %d (%s value)\n", mantissa_struct.denormalized, mantissa_struct.denormalized ? "Normalize" : "Denormalize");
printf("Mantissa \t: %s\n", mantissaBit);
printf("\n\nBit : %d %s %s\n", mantissa_struct.sign, exponentBit, mantissaBit);
// clean heap
free(exponentBit);
free(mantissaBit);
}
void getBitfrom32BitFloating(double num, struct mantissa_s *mantissa)
{
// store actual double value into struct
mantissa->actual = num;
// this is easy
// if positive, then 0, if negative, then 1
mantissa->sign = !(num > -1);
// convert num into positive number
if (num < 0)
num = -num;
struct standardNum sN;
getNormalizeValue(num, &sN);
// bias is the maximum value for signed bit representation
// for signed 32 bit, maximum number is 127
unsigned char bias = ~0;
bias /= 2;
// exponent is bias + loop_mormalize
mantissa->exponent = bias + sN.exponent;
// to store if there any denormalized number
// 1 for normalize, 0 for denormalized
mantissa->denormalized = mantissa->exponent != 0 ? 1 : 0;
// temp for mantissa
double t_mantissa = sN.num - (int)sN.num;
char shift_value = 22;
// initialized
mantissa->mantissa_bit = 0;
int i;
// get mantissa
for (i = 0; i < 23; i++)
{
t_mantissa *= 2;
if((int)t_mantissa)
mantissa->mantissa_bit = mantissa->mantissa_bit | 1 << shift_value;
t_mantissa -= (int)t_mantissa;
shift_value--;
}
}
void getNormalizeValue(double num, struct standardNum *sNa)
{
sNa->num = num;
sNa->exponent = 0;
while(1)
{
if ((int)sNa->num == 1)
break;
else
{
if (sNa->num < 1)
{
sNa->num *= 2;
sNa->exponent--;
}
else if (sNa->num > 1)
{
sNa->num /= 2;
sNa->exponent++;
}
}
}
}
char *num2BinCharStr(int dNum, int representNum)
{
// + 1 for null terminator (0x0)
char *store = (char *)malloc(representNum + 1);
// null terminated
store[representNum] = '\0';
int i;
for (i = 0; i < representNum; i++)
{
// iterate bit using reverse technique
store[i] = (dNum & ((uint32_t)(1 << (representNum - 1)) >> i)) ? '1' : '0';
}
// return dynamic memory pointer
return store;
}
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