int64_t divide crashing on cortex-m3
Wed Sep 21 21:31:00 GMT 2016
On 2016-09-21 12:46 PM, Richard Earnshaw (lists) wrote:
> movlt is a conditional instruction matching mov<c> where <c> == lt (less
> than). The instruction in cortex-m3 is used by prefixing it with an IT
> instruction which modifies the behaviour of subsequent instructions. So
> it lt
> movlt xxxx
> is perfectly legal on this processor.
> MOVT is a completely different instruction. It inserts a 16-bit value
> in the top half of the destination register, overwriting the previous
> bits in that register but leaving the lower half unchanged.
> This is all documented in the ARMv7-M version of the ARM ARM
> (registration required).
I'm not very familiar with conditional instruction matching, so I got
all excited when I thought I found a missing instruction. Sorry. Turns
out I was getting the hard fault because I had not enabled the other
fault handlers. The real fault is from a bus error.....Imprecise data
bus error = "data bus error has occurred, but the return address in the
stack frame is not related to the instruction that caused the error".
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