int64_t divide crashing on cortex-m3

Richard Earnshaw (lists)
Wed Sep 21 16:18:00 GMT 2016

On 21/09/16 17:10, drwho wrote:
> Hello,
> I am getting a hard exception fault when doing a divide on a int64_t on
> a cortex-m3.  Looking at the lss file, the compiler is doing the int64
> divide using __aeabi_ldivmod which uses the instruction movlt.  movlt is
> not supported by the cortex-m3.  How do I get gcc to use the right
> version of __aeabi_ldivmod?

movlt is perfectly legal on Cortex-m3 in IT blocks.

> CFLAGS = -MMD -MP -march=armv7-m -mcpu=cortex-m3 -mfix-cortex-m3-ldrd
> -mthumb -Wall -O3
> LDFLAG = -march=armv7-m -mcpu=cortex-m3 -mfix-cortex-m3-ldrd -mthumb
> -nostartfiles -Wl,--no-warn-mismatch -Wl,-dT sam3n.ld

You might want to remove the -Wl,--no-warn-mismatch and check that your
input files are correct.  This is a sledgehammer that disables a lot of
validation during linking.


> I'm using arm-none-eabi-gcc v5.3.1
> Jon

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