Thumb instruction set

E356356

The Thumb instruction set is a compact 16-bit subset of the ARM architecture designed to improve code density and efficiency on ARM-based processors.

All labels observed (2)

Label Occurrences
Thumb instruction set canonical 3
Thumb-2 instruction set 2

How this entity was disambiguated

Statements (44)

Predicate Object
instanceOf instruction set architecture
reduced instruction set computing extension
allows mixed ARM and Thumb code in the same program
alsoKnownAs ARM Thumb state
linked to: ARM
architectureFamily ARM
benefit potentially lower instruction cache miss rate
reduced memory footprint for firmware
smaller binaries compared to pure ARM code in many workloads
bitWidth 16-bit
category embedded processor technology
coexistsWith 32-bit ARM instruction set
compatibleWith ARM Cortex-M family
linked to: ARM Cortex-M series

ARM Cortex-R family
linked to: ARM Cortex-R series

ARM7TDMI
ARM9 family
linked to: ARM9

some ARM Cortex-A cores
designGoal improve code density
improve performance on memory-constrained systems
increase energy efficiency
reduce program memory usage
encodingLength 16-bit fixed-length instructions
executionModel decoded into full-width ARM operations internally on some cores
executionStateOf ARM architecture processor modes
hasSuccessor Thumb-2 instruction set
influenced ARM Cortex-M ISA design
linked to: ARM Cortex-M series
introducedBy ARM Holdings
linked to: ARM
introducedFor ARM-based processors
optimizationFor narrow instruction fetch path
systems with limited instruction memory bandwidth
partOf ARM architecture
linked to: ARM
requires ARMv4T or later architecture support
selectedBy T-bit in CPSR on ARMv4T and later
subsetOf ARM instruction set
linked to: ARM
supports arithmetic and logical instructions
conditional branch instructions
load and store instructions
targetUseCase code-size-sensitive applications
embedded systems
microcontrollers
tradeOff fewer available registers in many instructions compared to ARM state
reduced instruction encoding space for improved code density
usedIn consumer electronics with ARM cores
industrial control systems based on ARM MCUs
microcontrollers running real-time operating systems

How these facts were elicited

Referenced by (5)

Full triples — surface form annotated when it differs from this entity's canonical label.

Acorn RISC Machine supports Thumb instruction set
Thumb instruction set hasSuccessor Thumb-2 instruction set
linked to: Thumb instruction set
ARMv7-A supports Thumb-2 instruction set
subject linked to: ARMv7-A architecture
linked to: Thumb instruction set
ARMv5 supports Thumb instruction set
subject linked to: ARMv5 architecture
ARM Cortex-M series supports Thumb instruction set