projects / z180-stamp.git / blame
| Commit | Line | Data |
|---|---|---|
| e63b2f75 L |
1 | /* |
| 2 | * (c)2012 Michael Duane Rice All rights reserved. | |
| 3 | * | |
| 4 | * Redistribution and use in source and binary forms, with or without | |
| 5 | * modification, are permitted provided that the following conditions are | |
| 6 | * met: | |
| 7 | * | |
| 8 | * Redistributions of source code must retain the above copyright notice, this | |
| 9 | * list of conditions and the following disclaimer. Redistributions in binary | |
| 10 | * form must reproduce the above copyright notice, this list of conditions | |
| 11 | * and the following disclaimer in the documentation and/or other materials | |
| 12 | * provided with the distribution. Neither the name of the copyright holders | |
| 13 | * nor the names of contributors may be used to endorse or promote products | |
| 14 | * derived from this software without specific prior written permission. | |
| 15 | * | |
| 16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" | |
| 17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE | |
| 20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | |
| 21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | |
| 22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | |
| 23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | |
| 24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
| 25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 26 | * POSSIBILITY OF SUCH DAMAGE. | |
| 27 | */ | |
| 28 | ||
| 29 | /* $Id: system_tick.S 2348 2013-04-16 23:42:05Z swfltek $ */ | |
| 30 | ||
| 31 | /* | |
| 32 | Impoved system_tick Credit to Wouter van Gulik. | |
| 33 | */ | |
| 34 | ||
| 35 | #include <avr/common.h> | |
| 36 | ||
| 37 | .global system_tick | |
| 38 | .type system_tick, @function | |
| 39 | system_tick: | |
| 40 | push r24 | |
| 41 | in r24,_SFR_IO_ADDR(SREG) | |
| 42 | push r24 | |
| 43 | cli | |
| 44 | lds r24,__system_time+0 | |
| 45 | subi r24, (-1) | |
| 46 | sts __system_time+0,r24 | |
| 47 | lds r24,__system_time+1 | |
| 48 | sbci r24, (-1) | |
| 49 | sts __system_time+1,r24 | |
| 50 | lds r24,__system_time+2 | |
| 51 | sbci r24, (-1) | |
| 52 | sts __system_time+2,r24 | |
| 53 | lds r24,__system_time+3 | |
| 54 | sbci r24, (-1) | |
| 55 | sts __system_time+3,r24 | |
| 56 | pop r24 | |
| 57 | out _SFR_IO_ADDR(SREG),r24 | |
| 58 | pop r24 | |
| 59 | ret | |
| 60 | .size system_tick, .-system_tick |