Latest commit ca973bd Nov 3, 2016 @dpgeorge dpgeorge qemu-arm: Enable software floating point support, and float tests.
This helps to test floating point code on Cortex-M hardware.

As part of this patch the link-time-optimisation was disabled because it
wasn't compatible with software FP support.  In particular, the linker
could not find the __aeabi_f2d, __aeabi_d2f etc functions even though they
were provided by lib/libm/math.c.

This is experimental, community-supported port for Cortex-M emulation as provided by QEMU (

The purposes of this port are to enable:

  1. Continuous integration
    • run tests agains architecture-specific parts of code base
  2. Experimentation
    • simulation & prototyping of anything that has architecture-specific code
    • exploring instruction set in terms of optimising some part of MicroPython or a module
  3. Streamlined debugging
    • no need for JTAG or even an MCU chip itself
    • no need to use OpenOCD or anything else that might slow down the process in terms of plugging things together, pressing buttons, etc.

This port will only work with with GCC ARM Embedded toolchain and not with CodeSourcery toolchain. You will need to modify LDFLAGS if you want to use CodeSourcery's version of arm-none-eabi. The difference is that CodeSourcery needs -T generic-m-hosted.ld while ARM's version requires --specs=nano.specs --specs=rdimon.specs to be passed to the linker.