Thumb To improve compiled code density, processors since the ARM7TDMI (released in 1994) have featured the Thumb compressed instruction set, which have their own state. (The "T" in "TDMI" indicates the Thumb feature.) When in this state, the processor executes the Thumb instruction set, a compact 16-bit encoding for a subset of the ARM instruction set. Most of the Thumb instructions are directly mapped to normal ARM instructions. The space saving comes from making some of the instruction operands implicit and limiting the number of possibilities compared to the ARM instructions executed in the ARM instruction set state.
Thumb To improve compiled code density, processors si.nce the ARM7TDMI (released in 1994) have featured the Thumb compressed instruction set, which have their own state. (The "T" in "TDMI" indicates the Thu,mb feature.) When in this state, the processor executes the Thumb instr,uction set, a compact 16-bit encoding for a subset of the ARM instruction set. Most of the Thumb instructions are directly mapped to normal ARM instructions. The space saving comes from making some of the instruction operands, implicit and limiting the number of possibilities compared to the ARM instructions executed in the ARM instruction set state.