Keil GPIODATA Simulation issue with TivaC TM4C123GH6PM

Hello there,

I've an issue simulating GPIODATA bit-masking feature, in TivaC GPIODATA is virtually mapped to 256 Registers, each one gives the ability to access specific GPIO pins.

Unfortunately  it only works when using the last register which allow writing to all pins at once when masking with (0x3FC)

#define GPIOADATA ((volatile uint32*)(GPIOA_BASE_ADDRESS + 0x3FC))

But i can't use it to access only specific group of Pins such an example of accessing only PIN 0:

#define GPIOADATA ((volatile uint32*)(GPIOA_BASE_ADDRESS + 0x004))

Which allows me to avoid Read|Modify|Write operation by just typing (1 or 0) to the whole register being sure that at this address only PIN0 will be affected.

Hope you help me asap,

Thanks in advance