Add note about -mfloat-abi=hard versus -mfloat-abi=soft

This commit is contained in:
Uwe Bonnes 2013-01-21 13:50:02 +01:00
parent 747cc58c2c
commit 29fc42e419
1 changed files with 10 additions and 0 deletions

10
HACKING
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@ -44,6 +44,16 @@ over USB:
The device should reset and re-enumerate as a CDC-ACM device implementing
the GDB protocol.
Errors when compiling libopencm3
-------------------------------
If while compiling libopencm3 you get an error like
arm-none-eabi/bin/ld: error: cdcacm.elf uses VFP register arguments, \
arm-none-eabi/lib/thumb/v7m/libc.a(lib_a-memcpy-stub.o) does not
your toolchain and libopencm3 disagree on the calling convention for floation
point functions on the F4. Change in
lib/stm32/f4/Makefile and examples/stm32/f4/Makefile.include all apperance of
-mfloat-abi=hard to -mfloat-abi=soft
This doesn't matter for blackmagic, as it doesn't use floating point.
Compiling as a Linux application using FT2232 hardware
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