X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=device%2Flib%2Fpic16%2Flibsdcc%2Ffloat%2Ffsdiv.c;h=7126216a228a6b278da154c642465e90ed89033c;hb=bf6f6cf752b8248811eb665f2f01939958592cb7;hp=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391;hpb=db1268b4d51b6214bdca8028650704e3ab74f1ba;p=fw%2Fsdcc diff --git a/device/lib/pic16/libsdcc/float/fsdiv.c b/device/lib/pic16/libsdcc/float/fsdiv.c index e69de29b..7126216a 100644 --- a/device/lib/pic16/libsdcc/float/fsdiv.c +++ b/device/lib/pic16/libsdcc/float/fsdiv.c @@ -0,0 +1,100 @@ +/* +** libgcc support for software floating point. +** Copyright (C) 1991 by Pipeline Associates, Inc. All rights reserved. +** Permission is granted to do *anything* you want with this file, +** commercial or otherwise, provided this message remains intact. So there! +** I would appreciate receiving any updates/patches/changes that anyone +** makes, and am willing to be the repository for said changes (am I +** making a big mistake?). +** +** Pat Wood +** Pipeline Associates, Inc. +** pipeline!phw@motown.com or +** sun!pipeline!phw or +** uunet!motown!pipeline!phw +*/ + +/* +** $Id$ +*/ + +/* (c)2000/2001: hacked a little by johan.knol@iduna.nl for sdcc */ + +#include + +union float_long + { + float f; + long l; + }; + +/* divide two floats */ +float __fsdiv (float a1, float a2) +// reentrant +{ + volatile union float_long fl1, fl2; + volatile long result; + volatile unsigned long mask; + volatile long mant1, mant2; + volatile int exp ; + char sign; + + fl1.f = a1; + fl2.f = a2; + + /* subtract exponents */ + exp = EXP (fl1.l) ; + exp -= EXP (fl2.l); + exp += EXCESS; + + /* compute sign */ + sign = SIGN (fl1.l) ^ SIGN (fl2.l); + + /* divide by zero??? */ + if (!fl2.l) + /* return NaN or -NaN */ + return (-1.0); + + /* numerator zero??? */ + if (!fl1.l) + return (0); + + /* now get mantissas */ + mant1 = MANT (fl1.l); + mant2 = MANT (fl2.l); + + /* this assures we have 25 bits of precision in the end */ + if (mant1 < mant2) + { + mant1 <<= 1; + exp--; + } + + /* now we perform repeated subtraction of fl2.l from fl1.l */ + mask = 0x1000000; + result = 0; + while (mask) + { + if (mant1 >= mant2) + { + result |= mask; + mant1 -= mant2; + } + mant1 <<= 1; + mask >>= 1; + } + + /* round */ + result += 1; + + /* normalize down */ + exp++; + result >>= 1; + + result &= ~HIDDEN; + + /* pack up and go home */ + fl1.l = PACK (sign ? 1ul<<31 : 0, (unsigned long) exp, result); + return (fl1.f); +} +