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What should be LR(link register) value for Cortex-M7 core?

TS_Sanshin

I checked LR(link register) value about Cortex-M7 core with NUCLEO-H723ZG(STM32H723ZGT6).

As a result, when service routine is returned, LR value is PC address +1 as below.

PC=0x08001182

LR=0x08001183

Is this behavior correct one?

I expexted that LR and PC value are the same in this case.

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  • +1

    The least significant bit in the LR register specifies that the code at this address is a Thumb instruction and all Cortex-M instructions have Thumb encoding. So this behavior is expected. All instructions of Cortex-M cores must be located on even addresses.

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  • +1

    The least significant bit in the LR register specifies that the code at this address is a Thumb instruction and all Cortex-M instructions have Thumb encoding. So this behavior is expected. All instructions of Cortex-M cores must be located on even addresses.

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