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/* -*- Mode: Asm -*- */
/* Copyright (c) 2002 Michael Stumpf <mistumpf@de.pepperl-fuchs.com>
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.
*/
/*
frexp.S is part of FPlib V 0.3.0 ported to avr-as
for details see readme.fplib
*----------------------------------------------------------------------------------------
*
* A = mantissa(A) *integ = exponent(A)
* e.g.
* int integ
* double fract = frexp( 3.45, &integ ) = frexp ( 2^2 * 0.8625 )
* -> fract = 0.8625; *integ = 2
*
* fract(0) -> 0/0
*/
#if !defined(DOXYGEN)
#include "gasava.inc"
#include "fplib.inc"
TEXT_SEG(fplib, frexp)
FUNCTION(frexp)
GLOBAL(frexp)
MOV ZH,rPH
MOV ZL,rPL
BST rA3,7
RCALL _U(__fp_split1) ;
TST rA3
BREQ _frexp_200
SUBI rA3,0x7E ; 0.5 -> 0.5 * 2^0
; 1.0 -> 0.5 * 2^1
SBC rB0,rB0 ; sign expand rA3
ST Z,rA3
STD Z+1,rB0
ANDI rA2,0x7F ; mantissa is normalized
LDI rA3,0x3F ; exponent for 0.5
BLD rA3,7
RET
_frexp_200:
ST Z,rA3
STD Z+1,rT1c
RJMP _U(__fp_zero) ; frexp(0) returns 0 not A = 0x00800000 of fp_split1
ENDFUNC
#endif /* not DOXYGEN */
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