39 lines
1.2 KiB
Forth
39 lines
1.2 KiB
Forth
\ *****************************************************************************
|
|
\ * Copyright (c) 2004, 2008 IBM Corporation
|
|
\ * All rights reserved.
|
|
\ * This program and the accompanying materials
|
|
\ * are made available under the terms of the BSD License
|
|
\ * which accompanies this distribution, and is available at
|
|
\ * http://www.opensource.org/licenses/bsd-license.php
|
|
\ *
|
|
\ * Contributors:
|
|
\ * IBM Corporation - initial implementation
|
|
\ ****************************************************************************/
|
|
|
|
|
|
\ Use the HPET to calculate various frequencies.
|
|
|
|
\ Make HPET run.
|
|
1 10 hpet!
|
|
|
|
\ Set PMC1 to count CPU cycles.
|
|
f00 mmcr0!
|
|
|
|
d# 1000000000000000 4 hpet@ / CONSTANT hpet-freq
|
|
|
|
: get-times tbl@ pmc1@ f0 hpet@ ;
|
|
|
|
\ Calculate the CPU and TB frequencies.
|
|
: calibrate get-times dup >r swap >r swap >r hpet-freq d# 100 / + >r
|
|
BEGIN get-times dup r@ < WHILE 3drop REPEAT r> drop
|
|
rot r> - ffffffff and \ TB
|
|
rot r> - ffffffff and \ CPU
|
|
rot r> - >r \ HPET
|
|
hpet-freq * r@ / swap
|
|
hpet-freq * r> / ;
|
|
|
|
: round-to tuck 2/ + over / * ;
|
|
calibrate TO tb-frequency d# 100000000 round-to TO cpu-frequency
|
|
|
|
\ Stop HPET.
|
|
0 10 hpet!
|