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/* Copyright 2013-2014 IBM Corp.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
* implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
hello_kernel.S!
---------------
Because skiboot has its own stack, we don't even need that!
All we need to do is make an OPAL call to write to the console.
*/
. = 0x0
.globl _start
_start:
/*
* Save some values passed in from skiboot into registers that are
* non-volatile over OPAL calls.
* r8 is the OPAL base
* r9 is the OPAL entry point point
*/
mr %r13, %r8
mr %r14, %r9
bl here
here: mflr %r8 /* work out where we are running */
li %r0, 1 /* OPAL_CONSOLE_WRITE */
li %r3, 0 /* terminal 0 */
addi %r4, %r8, len - here /* ptr to length of string */
addi %r5, %r8, str - here /* ptr to string start */
mr %r2, %r13
mtctr %r14
bctrl
li %r0, 5 /* OPAL_CEC_POWER_DOWN */
mr %r2, %r13
mtctr %r14
bctrl
/* We shouldn't get here but if we do, just wait here */
b .
len:
.long 0x00
.long (strend - str)
str:
.string "Hello World!\n"
strend:
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