When creating a toolchain targeting an armv7-m core, such as cortex-m3 or cortex-m4, toolchain.eclass should configure gcc to default to thumb mode, otherwise any simple compilation unit fails with "error: target CPU does not support ARM mode". $ echo "int foo() { return 0; }" > conftest.c $ armv7m-elf-eabi-gcc -c conftest.c conftest.c:1:0: error: target CPU does not support ARM mode $ armv7m-elf-eabi-gcc -mthumb -c conftest.c $ echo $? 0 Please see the attached patch for the fix, which simply adds " --with-mode=thumb" to GCC's configure line. *Note*: newlib requires a patch for newlib/configure.host (use "arm*)" instead of "arm)") in order to properly compile... how this was overlooked, I have no idea. I'll submit that patch in a separate bug report. Reproducible: Always Steps to Reproduce: 1. crossdev --g 4.6.1-r1 --target armv7m-elf-eabi -P -v 2. 3.
Created attachment 310093 [details, diff] toolchain_eclass-default-to-thumb-mode-for-armv7m.patch
see #413547 for the newlib patch
bug #413547 ... hyperlink?
Created attachment 310115 [details, diff] /tmp/toolchain_eclass-default-to-thumb-mode-for-armv7m.patch v2 This patch has a couple of minor corrections that I noticed after testing 1) eliminate space after += 2) remove '?'
not an exact dupe, but largely the same issue *** This bug has been marked as a duplicate of bug 264534 ***
