The ARM7 core employs a 32-bit ARM instruction set with a subset of 16-bit instructions which still use 32-bit data and registers. This is done by using a Thumb state. In this state, the instructions are re-coded into 16 bits, improving code density by approximately 30% which reduces the amount of Flash needed. When Thumb instructions are executed, they are decompressed back to 32-bit instructions then decoded and executed. Therefore, all Thumb operations are still 32-bit.