CC1310 ddi r/w 为何搞这么复杂？

DDI 一些允许操作的REG 都是32位编址的，我看一下，DDI接口操作 API都搞得挺复杂。。。这是为何？ 
还有分 8位 16位 32位操作，，，手册上没有说明，，


__STATIC_INLINE void
AuxAdiDdiSafeWrite(uint32_t nAddr, uint32_t nData, uint32_t nSize)
{// Disable interrupts and remember whether to re-enablebool bIrqEnabled = !CPUcpsid();// Acquire semaphore for accessing ADI/DDI in AUX, perform access, release semaphorewhile (!HWREG(AUX_SMPH_BASE + AUX_SMPH_O_SMPH0));switch (nSize) {case 1:HWREGB(nAddr) = (uint8_t)nData; break;case 2:HWREGH(nAddr) = (uint16_t)nData; break;case 4: default:HWREG(nAddr)  = nData; break;}HWREG(AUX_SMPH_BASE + AUX_SMPH_O_SMPH0) = 1;// Restore interrupt enableif (bIrqEnabled) {CPUcpsie();}
}