bitmagic/main.c at master · VitHub/bitmagic · GitHub

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#include <stdio.h>

typedef unsigned int ui;

__declspec(naked) unsigned int reversebits32(ui n);


int main(int argc, char *argv[])
{


    int c,cc;

    for(c=0; c<=10; c++)
	   {
         cc = reversebits32(c);
		 printf(" %i : %i \n", c,cc);
	   }

    c = getchar();
    return 0;
}

// reverse32bit -- reverses the bits in a 32-bit number
__declspec(naked) unsigned int reversebits32(ui n)
{
 __asm {
        mov edx,[esp+4]   // EDX = n
		push ebx
		xor eax,eax       // EAX = 0
		xor ebx,ebx       // EBX = 0
		xor ecx,ecx       //
		inc ecx           // ECX = 1

		//mov ecx,32        //


 reversebits32_Loop:

        shr edx,cl
		adc eax,ebx
		shl eax,cl

        shr edx,cl
		adc eax,ebx
		shl eax,cl

        shr edx,cl
		adc eax,ebx
		shl eax,cl

        shr edx,cl
		adc eax,ebx
		shl eax,cl

		// loop reversebits32_Loop

        pop ebx
		ret
        //ret 4
   }
}