ARM7 printf long long int

Hi, my program does not do the expected things, printf a unsigned long long int.

#include <aduc7026.h>
#include"stdio.h"

void RS232_init(void);
int main (void)
{
	unsigned long long int A;
	RS232_init();
	printf("Start \n");
	while(1)
	{
		while(1)
		{
			printf("Enter a Hex-number\n");
			if (scanf("%X",&A)) break;
			scanf("%*");				//Clearing scanf input stream
		}
		printf ("Your input %64.64lX\n",A);
		A *= A;
		printf ("The result %64.64lX\n",A);
	}
}

void RS232_init(void)
{
	GP1CON = 0x011;			// Setup tx & rx pins on P1.0 and P1.1
   							// Start setting up UART at 9600bps
   	COMCON0 = 0x080;		// Setting DLAB
   	COMDIV0 = 0x088;		// Setting DIV0 and DIV1 to DL calculated
   	COMDIV1 = 0x000;
   	COMCON0 = 0x007;		// Clearing DLAB
}

the Output via RS232: Start Enter a Hex-number Your input 0000000000000000000000000000000000000000000000000000000011111111 The result 0000000000000000000000000000000000000000000000000000000087654321 Enter a Hex-number but when stepping through the programm ?C?QMUL?A: 0x00080F78 E08CB290 UMULL R11,R12,R0,R2 0x00080F7C E02CC192 MLA R12,R2,R1,R12 0x00080F80 E021C093 MLA R1,R3,R0,R12 0x00080F84 E1A0000B MOV R0,R11 0x00080F88 E12FFF1E BX R14 after the UMULL the expected result (0x0123456787654321) is in R12/R11 for some just a little moment... Sometimes i think C is the pureness of evil.