cvs commit: src/sys/ia64/ia64 trap.c

[Marcel Moolenaar]

marcel      2005-06-27 23:51:38 UTC

  FreeBSD src repository

  Modified files:
    sys/ia64/ia64        trap.c 
  Log:
  Handle B-unit break instructions. The break.b is unique in that the
  immediate is not saved by the architecture. Any of the break.{mifx}
  instructions have their immediate saved in cr.iim on interruption.
  Consequently, when we handle the break interrupt, we end up with a
  break value of 0 when it was a break.b. The immediate is important
  because it distinguishes between different uses of the break and
  which are defined by the runtime specification.
  The bottomline is that when the GNU debugger replaces a B-unit
  instruction with a break instruction in the inferior, we would not
  send the process a SIGTRAP when we encounter it, because the value
  is not one we recognize as a debugger breakpoint.
  
  This change adds logic to decode the bundle in which the break
  instruction lives whenever the break value is 0. The assumption
  being that it's a break.b and we fetch the immediate directly out
  of the instruction. If the break instruction was not a break.b,
  but any of break.{mifx} with an immediate of 0, we would be doing
  unnecessary work. But since a break 0 is invalid, this is not a
  problem and it will still result in a SIGILL being sent to the
  process.
  
  Approved by: re (scottl)
  
  Revision  Changes    Path
  1.113     +50 -1     src/sys/ia64/ia64/trap.c