thumbv7em-none-eabi and thumbv7em-none-eabihf

• Tier: 2
• Library Support: core and alloc (bare-metal, #![no_std])

Bare-metal target for CPUs in the Armv7E-M architecture family, supporting a subset of the T32 ISA.

Processors in this family include the:

• Arm Cortex-M4 and Arm Cortex-M4F
• Arm Cortex-M7 and Arm Cortex-M7F

See arm-none-eabi for information applicable to all arm-none-eabi targets, in particular the difference between the eabi and eabihf ABI.

Target maintainers

• Rust Embedded Devices Working Group Arm Team
• @rust-lang/arm-maintainers ([email protected])
  • Use @rustbot ping arm-maintainers to ping us

Target CPU and Target Feature options

See the bare-metal Arm docs for details on how to use these flags.

Table of supported CPUs for thumbv7em-none-eabi

CPU	FPU	DSP	Target CPU	Target Features
Any	No	Yes	None	None
Cortex-M4	No	Yes	cortex-m4	-fpregs
Cortex-M4F	SP	Yes	cortex-m4	None
Cortex-M7	No	Yes	cortex-m7	-fpregs
Cortex-M7F	SP	Yes	cortex-m7	-fp64
Cortex-M7F	DP	Yes	cortex-m7	None

Table of supported CPUs for thumbv7em-none-eabihf

CPU	FPU	DSP	Target CPU	Target Features
Any	SP	Yes	None	None
Cortex-M4F	SP	Yes	cortex-m4	None
Cortex-M7F	SP	Yes	cortex-m7	-fp64
Cortex-M7F	DP	Yes	cortex-m7	None

<div class="warning">

Never use the -fpregs target-feature with the thumbv7em-none-eabihf target as it will cause compilation units to have different ABIs, which is unsound.

</div>

Arm Cortex-M4 and Arm Cortex-M4F

The target CPU is cortex-m4.

• All Cortex-M4 have DSP extensions
  • support is controlled by the dsp target-feature
  • enabled by default with this target
• Cortex-M4F has a single precision FPU
  • support is enabled by default with this target-cpu
  • disable support using the -fpregs target-feature (eabi only)

Arm Cortex-M7 and Arm Cortex-M7F

The target CPU is cortex-m7.

• All Cortex-M7 have DSP extensions
  • support is controlled by the dsp target-feature
  • enabled by default with this target
• Cortex-M7F have either a single-precision or double-precision FPU
  • double-precision support is enabled by default with this target-cpu
    • opt-out by using the -f64 target-feature
  • disable support entirely using the -fpregs target-feature (eabi only)