The Thumb state register set is a subset of the ARM state set. In the Thumb state, the programmer has direct access to eight general purpose registers, r0 through r7, as well as the Program Counter (PC), the Stack Pointer (SP), a Link Register (LR), and the Current Program Status Register (CPSR). In the Thumb state, the higher registers, r8 through r12, are not part of the standard register set. This was one of the compromises made to be able to compress the Thumb mode into a 16-bit wide instruction. The assembly programmer has limited access to the registers r8 through r12, which allows them to be used for fast temporary storage.