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  • Committer: Bazaar Package Importer
  • Author(s): Hakan Ardo
  • Date: 2002-04-15 14:53:38 UTC
  • Revision ID: james.westby@ubuntu.com-20020415145338-c8hi0tn5bx74w7o3
Tags: upstream-20020203
Import upstream version 20020203

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libm/fplib/ldexp.S
 
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/*  -*- Mode: Asm -*-  */
 
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/*
 
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    ldexp.S is part of     FPlib V 0.3.0       ported to avr-as
 
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    for copyright and details see readme.fplib
 
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 *----------------------------------------------------------------------------------------
 
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 *
 
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 * A = 2^exp * x
 
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 * e.g.
 
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 * double y = ldexp( 3.45, 2 ) = 2^2 * 3.45 = 13.8
 
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 */
 
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#include "gasava.inc"
 
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#include "fplib.inc"
 
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          TEXT_SEG(fplib, ldexp)
 
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          FUNCTION(ldexp)
 
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GLOBAL(ldexp)
 
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        BST     rA3,7
 
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        RCALL   _U(__fp_split1)         ; clears rAE
 
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        TST     rA3                     ;
 
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        BREQ    _ldexp_01               ; 2^x*0 = 0
 
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        CPI     rPH,0xFF
 
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        BREQ    _ldexp_10               ; negative
 
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        TST     rPH
 
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        BREQ    _ldexp_10
 
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                                ; overflow or underflow
 
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 _dlexp_00:
 
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        BRPL    _ldexp_NaN              ; overflow
 
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 _ldexp_01:
 
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        RJMP    _U(__fp_zero)
 
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 _ldexp_NaN:
 
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        RJMP    _U(__fp_nanERANGE)      ; overflow
 
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 _ldexp_10:
 
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        ADD     rA3,rPL
 
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        adc     rT1c,rPH                ;
 
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                                ; check for overflow
 
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        BRNE    _ldexp_20
 
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 _ldexp_20:
 
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        RJMP    _U(__fp_merge)          ; rT0 must not be cleared : rAE=0 no rounding anyway
 
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          ENDFUNC
 
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