From 29fc42e4198029bb958d9feb68787b9d2eeb124f Mon Sep 17 00:00:00 2001 From: Uwe Bonnes Date: Mon, 21 Jan 2013 13:50:02 +0100 Subject: [PATCH] Add note about -mfloat-abi=hard versus -mfloat-abi=soft --- HACKING | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/HACKING b/HACKING index e79d573..ee1fc24 100644 --- a/HACKING +++ b/HACKING @@ -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 ------------------------------------------------------