diff options
Diffstat (limited to 'qemu/roms/SLOF/board-js2x/slof/freq.fs')
| -rw-r--r-- | qemu/roms/SLOF/board-js2x/slof/freq.fs | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/qemu/roms/SLOF/board-js2x/slof/freq.fs b/qemu/roms/SLOF/board-js2x/slof/freq.fs new file mode 100644 index 000000000..9f1d36d78 --- /dev/null +++ b/qemu/roms/SLOF/board-js2x/slof/freq.fs @@ -0,0 +1,39 @@ +\ ***************************************************************************** +\ * 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! |