Simulation for LPC1227

Good day!
I try debug in Keil simulator simple blinking program for LPC1227.
Program run, but in GPIO window fields PIN not changing(0x00).
Startup code generated by Keil master.
Problem in the program, simulator or startup code?
Thank you

part of program:

#define _BV(X) (1<<X)

int main(void)
{       LPC_SYSCON->SYSAHBCLKCTRL |= 0xE001001FUL;
        LPC_GPIO0->DIR = _BV(4)|_BV(5);
        LPC_GPIO0->SET = _BV(4)|_BV(5);

        /* Generate 1ms Ticks */
        SysTick_Config(SystemCoreClock / 1000);

while(1)
        {switch (msTicks)
                {
                case 500:
                        msTicks = 0;
                        LPC_GPIO0->CLR = _BV(4)|_BV(5);
                        break;
                case 100:
                case 200:
                case 300:
                        LPC_GPIO0->NOT = _BV(4)|_BV(5);
                        break;
                }
                __WFI();
        }
}