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Is it from a hard-coded register or address dependent? For eg, when does it go from privileged=1 to privileged=0?

syzygy
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  • In general it is useful to provide some context for your question, if you don't only people with this very specific knowledge can help you out whereas with context they can maybe point you to the right person or resources. – Dayde Aug 08 '18 at 15:44
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    @dayde The title is descriptive enough if you are familiar with these products, no different then asking some programming language question what does %c mean in printf in C. Folks that dont know C wont know what the question means but folks that do will....same with this question, pretty sad that it got closed so quickly... – old_timer Aug 08 '18 at 17:57
  • Saying that and looking it up I dont have access to a cortex-m bus to confirm anything and before the armv8-m is there a privileged mode that would use this. – old_timer Aug 08 '18 at 18:12
  • the cortex-m7 specifically calls this out. All transactions are data accesses, that is HPROTP[0] is always 1. On the cortex-m4 it appears we have control over hprot[1] (user access vs priveledged) and the cortex-m3 has yet another set of hits. remember at the end of the day this is just the arm core, the chip vendor then connects to this and chooses to support what they support of the amba/axi bus. – old_timer Aug 08 '18 at 18:17
  • I guess if it's as simple as "what does %c mean in printf in C" a documentation should answer the question thus indicating no search was made before asking – Dayde Aug 09 '18 at 10:00
  • @Dayde Either that, or the relevant documentation is split across part, processor and architecture specific documents in such a way as to be hard to find a reliable or consistent answer. Particularly with ARM-v8M this is a useful (if rather brief) question. – Sean Houlihane Aug 10 '18 at 08:30
  • I get it I'm not familiar with the subject, however I'd be glad to upvote this question if it was asked a bit more like this one https://stackoverflow.com/questions/3764119/arm-cortex-m3-how-do-i-determine-the-program-counter-value-before-a-hard-fault?rq=1 – Dayde Aug 10 '18 at 12:28

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