• State Not Answered
  • Locked Locked
  • Replies 8 replies
  • Subscribers 349 subscribers
  • Views 7392 views
  • Users 0 members are here
Options
Related
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

purpose of RSDIS in ACTLR ?

Sylvain

Hello,

What is the purpose of the RSDIS (Return Stack DISable) bit in ACTLR ?

What would be the consequence on code execution if set DISable ?

Is the software able to write this bit ?

Thanks for help

Parents
  • 0 in reply to Yasuhiko Koumoto

    Hi,

    I was comparing the DDI460D text to your first answer which quotes "...is not frozen" ( extract of ARM DDI 0363G).

    They are different : first one says frozen, second one sys not frozen

    I don't think this makes any difference in processor behavior but it remains the documents are not coherent.

    Best regards,

    Sylvain

Reply
  • 0 in reply to Yasuhiko Koumoto

    Hi,

    I was comparing the DDI460D text to your first answer which quotes "...is not frozen" ( extract of ARM DDI 0363G).

    They are different : first one says frozen, second one sys not frozen

    I don't think this makes any difference in processor behavior but it remains the documents are not coherent.

    Best regards,

    Sylvain

Children
  • 0 in reply to Sylvain

    There are discrepancies between the two documents but in this case it is not an error. When RSDIS is set, the return address stack pointer behaves differently in Cortex-R4 and Cortex-R5. If you will notice, when the prediction is forced to a fixed direction (through the BP field in the ACTLR),  the global history table also behaves differently.