| /* Copyright (c) 2002 Michael Stumpf <mistumpf@de.pepperl-fuchs.com> |
| Copyright (c) 2006 Dmitry Xmelkov |
| All rights reserved. |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions are met: |
| |
| * Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| * Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in |
| the documentation and/or other materials provided with the |
| distribution. |
| * Neither the name of the copyright holders nor the names of |
| contributors may be used to endorse or promote products derived |
| from this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
| AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
| LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| POSSIBILITY OF SUCH DAMAGE. */ |
| |
| /* $Id: acos.S 2191 2010-11-05 13:45:57Z arcanum $ */ |
| |
| /* float acos (float x); |
| The acos() function calculates the arc cosine of x; that is the value |
| whose cosine is x. |
| */ |
| |
| |
| #if !defined(__AVR_TINY__) |
| |
| #include "fp32def.h" |
| #include "asmdef.h" |
| |
| #define HI40_PI 0x40490FDA /* Pi */ |
| #define LO40_PI 0xA2 |
| |
| ENTRY acos |
| ; save A sign |
| push rA3 |
| ; A = arccos(fabs(A)) |
| andi rA3, 0x7f |
| rcall _U(__fp_arccos) |
| ; check sign |
| pop r0 |
| tst r0 |
| brpl 1f |
| ; for negative x: arccos(x) = Pi - arccos(-x) |
| subi rA3, 0x80 |
| ldi rBE, LO40_PI |
| ldi rB0, lo8(HI40_PI) |
| ldi rB1, hi8(HI40_PI) |
| ldi rB2, hlo8(HI40_PI) |
| ldi rB3, hhi8(HI40_PI) |
| rcall _U(__addsf3x) |
| ; round |
| 1: rjmp _U(__fp_round) |
| ENDFUNC |
| |
| #endif /* !defined(__AVR_TINY__) */ |
