• Locked Locked
  • Replies 4 replies
  • Subscribers 119 subscribers
  • Views 5427 views
  • Users 0 members are here
2025 survey

We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.

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

Question about Program counter

Camp Phor
Note: This was originally posted on 1st October 2012 at http://forums.arm.com

[size=2]Hey[/size]

[size=2]Can someone please explain why instructions that modify the value of the PC (such as branches or [/size][size=2]mov pc, lr[/size][size=2]) requireadditional clock cycles to execute than those who don't operate on the PC. [/size]

[size=2]does branch link modify the value of PC or LR?[/size]

[size=2]
[/size]

[size=2]thanks [/size]

Parents
  • Note: This was originally posted on 2nd October 2012 at http://forums.arm.com

    [size=2]awesome, thanks heaps.[/size]
    [size=2] [/size]
    [size=2]I've actually got heaps of questions i would like to ask...haha[/size]

    [size=2][size=2][size=2]What does the [/size][size=2]rsb [/size][size=2]instruction do?  we'll i know what it does but don't fully understand why we would use rsb rather than sub...?[/size][/size][/size]
    [size=2][size=2][size=2] [/size][/size][/size]
    [size=2][size=2][size=2]could someone give an example of an expression that would require the use of rsb rather than sub?[/size][/size][/size]
    [size=2][size=2][size=2] [/size][/size][/size]
    [size=2][size=2][size=2]thanks heaps~[/size][/size][/size]
Reply
  • Note: This was originally posted on 2nd October 2012 at http://forums.arm.com

    [size=2]awesome, thanks heaps.[/size]
    [size=2] [/size]
    [size=2]I've actually got heaps of questions i would like to ask...haha[/size]

    [size=2][size=2][size=2]What does the [/size][size=2]rsb [/size][size=2]instruction do?  we'll i know what it does but don't fully understand why we would use rsb rather than sub...?[/size][/size][/size]
    [size=2][size=2][size=2] [/size][/size][/size]
    [size=2][size=2][size=2]could someone give an example of an expression that would require the use of rsb rather than sub?[/size][/size][/size]
    [size=2][size=2][size=2] [/size][/size][/size]
    [size=2][size=2][size=2]thanks heaps~[/size][/size][/size]
Children
No data