Programa para converter float para o padrão ieee754 (binario)

float_to_ieee754.c

#include <stdio.h>  
#include <malloc.h>           
#include <string.h>

#if __USE_SSE__
void reverse(char *begin, char *end)
{
	_asm
	{
		mov edx, DWORD PTR[begin]
		mov eax, DWORD PTR[end]
		
	Loop_tamanho:
		cmp edx, eax
		jnb Sair
		movzx ecx, BYTE PTR[edx]
		movzx ebx, BYTE PTR[eax]
		mov BYTE PTR[edx], bl
		mov BYTE PTR[eax], cl
		add edx, 1
		sub eax, 1
		jmp Loop_tamanho
	Sair:
	}
}

const unsigned char vrev[] = { 15,14,13,12,11,10,9,8,7,6,5,4,3,2,1,0 };
void vreverse(char *begin, char *end)
{
	__asm
	{
		mov eax, DWORD PTR[begin]
		mov edx, DWORD PTR[end]
		mov ecx, edx
		sub ecx, eax
		add ecx, 1
	Loop_inicio:
		cmp ecx, 15
		jle Reverte
		movdqu	xmm1, XMMWORD PTR[eax]
		movdqu	xmm0, XMMWORD PTR[edx - 15]
		movdqa	xmm2, XMMWORD PTR[vrev]    
		pshufb	xmm1, xmm2
		pshufb	xmm0, xmm2
		movups	XMMWORD PTR[edx - 15], xmm1
		movups	XMMWORD PTR[eax], xmm0
		add	eax, 16
		sub	edx, 16
		sub	ecx, 32
		jmp	Loop_inicio
	
	Reverte:
		cmp ecx, 1
		jle Sair
		push edx
		push eax
		call reverse
		add esp, 8
	Sair:
	}
}
#else
char *strrev_t(char *str)
{
	char *p1, *p2;

	if (!str || !*str)
		return str;
	for (p1 = str, p2 = str + strlen(str) - 1; p2 > p1; ++p1, --p2)
	{
		*p1 ^= *p2;
		*p2 ^= *p1;
		*p1 ^= *p2;
	}
	return str;
}
#endif

void floatToBinary(float f, char *str, int numeroDeBits)
{
	int i = 0;
	int strIndex = 0;
	union
	{
		float f;
		unsigned int i;
	}u;
	u.f = f;
	memset(str, '0', numeroDeBits);

	for (i = 0; i < numeroDeBits; i++)
	{
		str[strIndex++] = (u.i & (1 << 0)) ? '1' : '0';
		u.i >>= 1;
	}

  	str[strIndex] = '\0';
  
#if __USE_SSE__
	vreverse(str, str+strIndex-1);
#else
	str = strrev_t(str);
#endif
}

int main()
{
	float input = 0.0;
	const int numeroDeBits = 32;
	char *str = (char*)malloc(sizeof(char) * numeroDeBits);
	printf("Digite um numero float: ");
	scanf("%f", &input);
	floatToBinary(input, str, numeroDeBits);
	printf("%s\n", str);
	free(str);     
	return 0;
}