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range of BL instruction in arm state

BASIL BABY

range of BL instruction in arm state is + or - 32MB as per instruction set.how...........?

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    The ARM BL instruction has a 24-bit immediate for encoding the branch offset (see section A8.8.25 of the ARMv7-A/R Architecture Reference Manual).

    This would give you a range of 2^24 bytes, or +/-8MB (given that the immediate has include whether it forwards or backwards).  However, all ARM instructions are 4 bytes long, and must be size aligned.  Because of this we don't have to worry about the two least significant bits of the address - taking our branch range from +/-8MB to +/-32MB.

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    The ARM BL instruction has a 24-bit immediate for encoding the branch offset (see section A8.8.25 of the ARMv7-A/R Architecture Reference Manual).

    This would give you a range of 2^24 bytes, or +/-8MB (given that the immediate has include whether it forwards or backwards).  However, all ARM instructions are 4 bytes long, and must be size aligned.  Because of this we don't have to worry about the two least significant bits of the address - taking our branch range from +/-8MB to +/-32MB.

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