#8 sim freezes with empty program

open
Fuat Keceli
3
2009-04-15
2009-04-15
George Caragea
No

When compiling an empty XMTC program (where the main function doesn't do anything), the XMT cycle-accurate execution never terminates.
Here's an example:

[george@ride emptyprog_bug]$ xmtcc -q -o ser-s ser-s.c
[george@ride emptyprog_bug]$ xmtsim -v
XMT Simulator
Simulator Version: 0.81.101.r8206
Java Version: 1.6.0_11
[george@ride emptyprog_bug]$ xmtsim -cycle -timer 5 -count ser-s.sim -binload ser-s.b
Real time: 5.00 sec.
Simulation time: 15380771 cycles
Number of instructions: 6
Number of serial instructions: 6
Number of parallel instructions: 0
==============================
Real time: 10.00 sec.
Simulation time: 31717368 cycles
Number of instructions: 6
Number of serial instructions: 6
Number of parallel instructions: 0
==============================

Discussion

  • George Caragea
    George Caragea
    2009-04-15

    an empty program

     
    Attachments
  • Fuat Keceli
    Fuat Keceli
    2009-04-16

    It is a nasty bug related to temporary branch prediction replacement that I
    had in place. On the bright side it will be solved when full branch
    prediction will be implemented which is not very hard. I assume this is not
    very urgent. I should come around to it sometime this week.