GitLab

  Optimised the default IrqV handler.
Detail:
  * OS_ReadSysInfo 6 tells grubby programs lots of grubby info. This
    has been extended to include:

      18 - relocated base of OS SWI despatch table
      19 - relocated base of IRQ device head nodes
      20 - relocated end of IRQ device head nodes
      21 - top of the IRQ stack

    These values are known to be useful for debugging purposes.

  * The default IrqV handler gets the device number times three on
    entry in R0. It then went through a loop subtracting three and
    incrementing a counter to divide by three.

    This has been replaced by four ARM instructions which should
    give the same results (three to divide by three and one to set
    R0 to zero - as the old code did).

    If the device number is outside the range 0..31, the new code
    may produce inaccurate results, but this should not happen.
Admin:
  Not tested ;)

Version 5.43. Tagged as 'Kernel-5_43'