| /* Copyright (c) 2002 Michael Stumpf <mistumpf@de.pepperl-fuchs.com> |
| Copyright (c) 2006,2009 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: modf.S 2191 2010-11-05 13:45:57Z arcanum $ */ |
| |
| #if !defined(__AVR_TINY__) |
| |
| #include "fp32def.h" |
| #include "asmdef.h" |
| |
| /* double modf (double x, double *iptr); |
| |
| The modf() function breaks the argument x into an integral part and a |
| fractional part, each of which has the same sign as x. The integral part |
| is stored in iptr. |
| This implementation skips writing by zero pointer. |
| */ |
| |
| #define iptr_lo r20 |
| |
| ENTRY modf |
| ENTRY modff |
| ; save iptr |
| X_movw ZL, iptr_lo |
| ; XH = exponent field |
| X_movw XL, rA2 |
| lsl XL |
| rol XH |
| ; B = A |
| X_movw rB0, rA0 |
| X_movw rB2, rA2 |
| ; Is there an integral part? |
| subi XH, 127 ; exp of 1.0 |
| brsh 1f |
| ; fabs(x) < 1.0: *iptr = copysign(0, x), return x |
| clr rB0 |
| clr rB1 |
| clr rB2 |
| andi rB3, 0x80 |
| rjmp .L_write |
| ; Is there a fraction part? |
| 1: subi XH, 23 |
| brsh 4f ; no fraction part |
| ; check fraction: B >>= 23 - (exp-127) |
| mov XL, XH ; Now XH is -23..-1 |
| clr r0 ; to control, is the fraction zero? |
| 2: lsr rB2 |
| ror rB1 |
| ror rB0 |
| adc r0, r1 |
| inc XL |
| brmi 2b |
| tst r0 |
| breq .L_nfrc ; fraction == 0 |
| ; restore and clear fraction: B <<= 23 - (exp-127) |
| 3: lsl rB0 |
| rol rB1 |
| rol rB2 |
| inc XH |
| brmi 3b |
| ; write B |
| rcall .L_write |
| ; return nonzero fraction: A - B |
| rjmp _U(__subsf3) |
| ; exponent too big: compare with smallest NaN (0x7f800001) |
| 4: cpi rA0, 1 |
| cpc rA1, r1 |
| ldi XL, 0x80 |
| cpc rA2, XL |
| sbci XH, 128 - 23 |
| brsh .L_write ; NaN: write and return as is |
| ; fraction == 0 |
| .L_nfrc: |
| X_movw rB0, rA0 |
| X_movw rB2, rA2 |
| ; A = 0.0 with sign |
| clr rA0 |
| clr rA1 |
| clr rA2 |
| andi rA3, 0x80 |
| .L_write: |
| adiw ZL, 0 ; skip writing with NULL pointer |
| breq 1f |
| st Z, rB0 |
| std Z+1, rB1 |
| std Z+2, rB2 |
| std Z+3, rB3 |
| 1: ret |
| ENDFUNC |
| |
| #endif /* !defined(__AVR_TINY__) */ |
