Allocates a new ALAT entry using the register type specified by rtype, the register address specified by raddr, the physical memory address specified by paddr, and the access size specified by size. No value is returned. This function guarantees that only one ALAT entry exists for a given raddr. If a ld.c.nc, ldf.c.nc, or ldfp.c.nc instruction's raddr matches an existing ALAT entry's register tag, but the instruction's size and/or paddr are different than that of the existing entry's; then this function may either preserve the existing entry, or invalidate it and write a new entry with the instruction's specified size and paddr.