iec man page on DigitalUNIX

Man page or keyword search:  
man Server   12896 pages
apropos Keyword Search (all sections)
Output format
DigitalUNIX logo
[printable version]

iec(1)									iec(1)

       iec - Instruction Emulator Control

       iec p | s [value]

       iec p | s [keyword]

       The  following  options are used with the iec command: Sets or displays
       the current option setting for the parent process.   Sets  or  displays
       the current option setting for the system.

       The  following  keywords are used with the p option: Resets the current
       option settings to the default settings for the parent  process.	  Does
       not  print  the	instruction  emulation	warning message for the parent
       process.	 Disables instruction emulation.  Any programs that attempt to
       execute	instructions  that  are	 not implemented in the host processor
       will receive the	 SIGILL	 (illegal  instruction)	 signal.   Prints  the
       instruction emulation warning messages for all instances of instruction
       emulation.  By default,	a  message  is	only  printed  for  the	 first

       The  following  keywords are used with the s option: Resets the current
       option settings to the default settings for the system.	Does not print
       the instruction emulation warning message for the system.

       If  value  is  not  specified, the current option setting is displayed.
       You can specify value as either 0 (zero) or 1 (one).   If  value	 is  0
       (zero),	the  option  is	 turned	 on and messages are not displayed. If
       value is 1 (one), the option is turned off and messages are displayed.

       Keywords can be used singly or in any combination.  However, the	 reset
       keyword overrides any other keywords that it is used with.

       Usually, the parent process is the shell.

       Some  processors	 in the Alpha processor family do not implement all of
       the instructions defined in the Alpha architecture.  The operating sys‐
       tem  provides an instruction emulator that permits all programs written
       for the Alpha architecture to run, regardless of	 the  Alpha  processor
       being used.

       When  the operating system encounters an instruction that is not imple‐
       mented by the host processor, the default  action  is  to  emulate  the
       instruction  and	 print	a  message informing the user process that the
       emulation has occurred.	By default, the operating system prints a mes‐
       sage only for the first instance of emulation, although it continues to
       emulate any other non-implemented instructions that it encounters.  The
       message	has  the  form:	 “inst	emulated pid=nnn <prog_name> va=0xvir‐
       tual_addrpc=0xpc_addr  inst=0xactual_instr”.  Receiving	this   message
       tells you that your application will run at less than its optimal level
       of performance.	You may wish to recompile your program to  get	better
       performance.  For information on how to compile for a specific hardware
       platform, see the compiler manpage for the language you are using.

       In addition, the default action for the	operating  system  is  to  not
       deliver a SIGILL signal to the parent process when an emulated instruc‐
       tion is encountered.

       These defaults are satisfactory for most users, but some users  require
       a different behavior and want to specify their own Instruction Emulator
       Control (IEC).

       The iec command enables or disables the display of “inst emulated” mes‐
       sages.  The  command  sets or displays the IEC_NOPRINT, IEC_NOEMUL, and
       IEC_VERBOSE flags, as defined in setsysinfo(2).

       You must be superuser to set the system option.

       Both of the following commands disable messages for the parent process:
       # iec p 0

       #  iec p noprint Both of the following commands enable messages for the
       system: # iec s 1

       # iec s reset The following command enables the printing of  a  message
       for each emulated instruction: # iec p verbose

       getsysinfo(2), setsysinfo(2)


List of man pages available for DigitalUNIX

Copyright (c) for man pages and the logo by the respective OS vendor.

For those who want to learn more, the polarhome community provides shell access and support.

[legal] [privacy] [GNU] [policy] [cookies] [netiquette] [sponsors] [FAQ]
Polarhome, production since 1999.
Member of Polarhome portal.
Based on Fawad Halim's script.
Vote for polarhome
Free Shell Accounts :: the biggest list on the net