qemu/roms/SLOF/board-js2x/slof/freq.fs

   1 \ *****************************************************************************
   2 \ * Copyright (c) 2004, 2008 IBM Corporation
   3 \ * All rights reserved.
   4 \ * This program and the accompanying materials
   5 \ * are made available under the terms of the BSD License
   6 \ * which accompanies this distribution, and is available at
   7 \ * http://www.opensource.org/licenses/bsd-license.php
   8 \ *
   9 \ * Contributors:
  10 \ *     IBM Corporation - initial implementation
  11 \ ****************************************************************************/
  12
  13
  14 \ Use the HPET to calculate various frequencies.
  15
  16 \ Make HPET run.
  17 1 10 hpet!
  18
  19 \ Set PMC1 to count CPU cycles.
  20 f00 mmcr0!
  21
  22 d# 1000000000000000 4 hpet@ / CONSTANT hpet-freq
  23
  24 : get-times  tbl@ pmc1@ f0 hpet@ ;
  25
  26 \ Calculate the CPU and TB frequencies.
  27 : calibrate  get-times dup >r swap >r swap >r hpet-freq d# 100 / + >r
  28              BEGIN get-times dup r@ < WHILE 3drop REPEAT r> drop
  29              rot r> - ffffffff and \ TB
  30              rot r> - ffffffff and \ CPU
  31              rot r> - >r           \ HPET
  32              hpet-freq * r@ / swap
  33              hpet-freq * r> / ;
  34
  35 : round-to  tuck 2/ + over / * ;
  36 calibrate TO tb-frequency d# 100000000 round-to TO cpu-frequency
  37
  38 \ Stop HPET.
  39 0 10 hpet!