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596 lines
12 KiB
C
596 lines
12 KiB
C
/* This is a stripped down version of floatlib.c. It supplies only those
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functions which exist in libgcc, but for which there is not assembly
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language versions in m68k/lb1sf68.S.
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It also includes simplistic support for extended floats (by working in
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double precision). You must compile this file again with -DEXTFLOAT
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to get this support. */
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/*
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** gnulib support for software floating point.
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** Copyright (C) 1991 by Pipeline Associates, Inc. All rights reserved.
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** Permission is granted to do *anything* you want with this file,
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** commercial or otherwise, provided this message remains intact. So there!
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** I would appreciate receiving any updates/patches/changes that anyone
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** makes, and am willing to be the repository for said changes (am I
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** making a big mistake?).
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**
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** Pat Wood
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** Pipeline Associates, Inc.
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** pipeline!phw@motown.com or
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** sun!pipeline!phw or
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** uunet!motown!pipeline!phw
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**
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** 05/01/91 -- V1.0 -- first release to gcc mailing lists
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** 05/04/91 -- V1.1 -- added float and double prototypes and return values
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** -- fixed problems with adding and subtracting zero
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** -- fixed rounding in truncdfsf2
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** -- fixed SWAP define and tested on 386
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*/
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/*
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** The following are routines that replace the gnulib soft floating point
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** routines that are called automatically when -msoft-float is selected.
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** The support single and double precision IEEE format, with provisions
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** for byte-swapped machines (tested on 386). Some of the double-precision
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** routines work at full precision, but most of the hard ones simply punt
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** and call the single precision routines, producing a loss of accuracy.
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** long long support is not assumed or included.
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** Overall accuracy is close to IEEE (actually 68882) for single-precision
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** arithmetic. I think there may still be a 1 in 1000 chance of a bit
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** being rounded the wrong way during a multiply. I'm not fussy enough to
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** bother with it, but if anyone is, knock yourself out.
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**
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** Efficiency has only been addressed where it was obvious that something
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** would make a big difference. Anyone who wants to do this right for
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** best speed should go in and rewrite in assembler.
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**
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** I have tested this only on a 68030 workstation and 386/ix integrated
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** in with -msoft-float.
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*/
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/* the following deal with IEEE single-precision numbers */
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#define EXCESS 126L
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#define SIGNBIT 0x80000000L
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#define HIDDEN (1L << 23L)
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#define SIGN(fp) ((fp) & SIGNBIT)
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#define EXP(fp) (((fp) >> 23L) & 0xFF)
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#define MANT(fp) (((fp) & 0x7FFFFFL) | HIDDEN)
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#define PACK(s,e,m) ((s) | ((e) << 23L) | (m))
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/* the following deal with IEEE double-precision numbers */
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#define EXCESSD 1022L
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#define HIDDEND (1L << 20L)
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#define EXPDBITS 11
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#define EXPDMASK 0x7FFL
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#define EXPD(fp) (((fp.l.upper) >> 20L) & 0x7FFL)
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#define SIGND(fp) ((fp.l.upper) & SIGNBIT)
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#define MANTD(fp) (((((fp.l.upper) & 0xFFFFF) | HIDDEND) << 10) | \
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(fp.l.lower >> 22))
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#define MANTDMASK 0xFFFFFL /* mask of upper part */
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/* the following deal with IEEE extended-precision numbers */
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#define EXCESSX 16382L
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#define HIDDENX (1L << 31L)
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#define EXPXBITS 15
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#define EXPXMASK 0x7FFF
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#define EXPX(fp) (((fp.l.upper) >> 16) & EXPXMASK)
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#define SIGNX(fp) ((fp.l.upper) & SIGNBIT)
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#define MANTXMASK 0x7FFFFFFFL /* mask of upper part */
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union double_long
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{
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double d;
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struct {
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long upper;
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unsigned long lower;
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} l;
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};
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union float_long {
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float f;
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long l;
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};
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union long_double_long
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{
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long double ld;
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struct
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{
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long upper;
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unsigned long middle;
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unsigned long lower;
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} l;
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};
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#ifndef EXTFLOAT
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int
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__unordsf2(float a, float b)
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{
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union float_long fl;
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fl.f = a;
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if (EXP(fl.l) == EXP(~0u) && (MANT(fl.l) & ~HIDDEN) != 0)
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return 1;
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fl.f = b;
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if (EXP(fl.l) == EXP(~0u) && (MANT(fl.l) & ~HIDDEN) != 0)
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return 1;
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return 0;
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}
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int
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__unorddf2(double a, double b)
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{
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union double_long dl;
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dl.d = a;
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if (EXPD(dl) == EXPDMASK
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&& ((dl.l.upper & MANTDMASK) != 0 || dl.l.lower != 0))
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return 1;
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dl.d = b;
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if (EXPD(dl) == EXPDMASK
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&& ((dl.l.upper & MANTDMASK) != 0 || dl.l.lower != 0))
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return 1;
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return 0;
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}
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/* convert unsigned int to double */
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double
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__floatunsidf (unsigned long a1)
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{
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long exp = 32 + EXCESSD;
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union double_long dl;
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if (!a1)
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{
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dl.l.upper = dl.l.lower = 0;
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return dl.d;
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}
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while (a1 < 0x2000000L)
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{
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a1 <<= 4;
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exp -= 4;
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}
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while (a1 < 0x80000000L)
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{
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a1 <<= 1;
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exp--;
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}
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/* pack up and go home */
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dl.l.upper = exp << 20L;
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dl.l.upper |= (a1 >> 11L) & ~HIDDEND;
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dl.l.lower = a1 << 21L;
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return dl.d;
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}
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/* convert int to double */
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double
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__floatsidf (long a1)
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{
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long sign = 0, exp = 31 + EXCESSD;
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union double_long dl;
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if (!a1)
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{
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dl.l.upper = dl.l.lower = 0;
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return dl.d;
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}
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if (a1 < 0)
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{
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sign = SIGNBIT;
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a1 = (long)-(unsigned long)a1;
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if (a1 < 0)
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{
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dl.l.upper = SIGNBIT | ((32 + EXCESSD) << 20L);
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dl.l.lower = 0;
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return dl.d;
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}
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}
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while (a1 < 0x1000000L)
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{
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a1 <<= 4;
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exp -= 4;
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}
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while (a1 < 0x40000000L)
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{
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a1 <<= 1;
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exp--;
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}
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/* pack up and go home */
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dl.l.upper = sign;
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dl.l.upper |= exp << 20L;
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dl.l.upper |= (a1 >> 10L) & ~HIDDEND;
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dl.l.lower = a1 << 22L;
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return dl.d;
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}
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/* convert unsigned int to float */
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float
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__floatunsisf (unsigned long l)
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{
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double foo = __floatunsidf (l);
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return foo;
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}
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/* convert int to float */
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float
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__floatsisf (long l)
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{
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double foo = __floatsidf (l);
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return foo;
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}
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/* convert float to double */
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double
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__extendsfdf2 (float a1)
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{
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register union float_long fl1;
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register union double_long dl;
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register long exp;
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register long mant;
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fl1.f = a1;
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dl.l.upper = SIGN (fl1.l);
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if ((fl1.l & ~SIGNBIT) == 0)
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{
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dl.l.lower = 0;
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return dl.d;
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}
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exp = EXP(fl1.l);
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mant = MANT (fl1.l) & ~HIDDEN;
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if (exp == 0)
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{
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/* Denormal. */
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exp = 1;
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while (!(mant & HIDDEN))
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{
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mant <<= 1;
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exp--;
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}
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mant &= ~HIDDEN;
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}
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exp = exp - EXCESS + EXCESSD;
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dl.l.upper |= exp << 20;
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dl.l.upper |= mant >> 3;
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dl.l.lower = mant << 29;
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return dl.d;
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}
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/* convert double to float */
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float
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__truncdfsf2 (double a1)
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{
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register long exp;
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register long mant;
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register union float_long fl;
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register union double_long dl1;
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int sticky;
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int shift;
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dl1.d = a1;
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if ((dl1.l.upper & ~SIGNBIT) == 0 && !dl1.l.lower)
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{
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fl.l = SIGND(dl1);
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return fl.f;
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}
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exp = EXPD (dl1) - EXCESSD + EXCESS;
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sticky = dl1.l.lower & ((1 << 22) - 1);
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mant = MANTD (dl1);
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/* shift double mantissa 6 bits so we can round */
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sticky |= mant & ((1 << 6) - 1);
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mant >>= 6;
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/* Check for underflow and denormals. */
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if (exp <= 0)
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{
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if (exp < -24)
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{
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sticky |= mant;
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mant = 0;
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}
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else
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{
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sticky |= mant & ((1 << (1 - exp)) - 1);
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mant >>= 1 - exp;
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}
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exp = 0;
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}
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/* now round */
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shift = 1;
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if ((mant & 1) && (sticky || (mant & 2)))
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{
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int rounding = exp ? 2 : 1;
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mant += 1;
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/* did the round overflow? */
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if (mant >= (HIDDEN << rounding))
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{
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exp++;
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shift = rounding;
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}
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}
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/* shift down */
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mant >>= shift;
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mant &= ~HIDDEN;
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/* pack up and go home */
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fl.l = PACK (SIGND (dl1), exp, mant);
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return (fl.f);
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}
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/* convert double to int */
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long
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__fixdfsi (double a1)
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{
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register union double_long dl1;
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register long exp;
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register long l;
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dl1.d = a1;
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if (!dl1.l.upper && !dl1.l.lower)
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return 0;
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exp = EXPD (dl1) - EXCESSD - 31;
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l = MANTD (dl1);
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if (exp > 0)
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{
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/* Return largest integer. */
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return SIGND (dl1) ? 0x80000000L : 0x7fffffffL;
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}
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if (exp <= -32)
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return 0;
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/* shift down until exp = 0 */
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if (exp < 0)
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l >>= -exp;
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return (SIGND (dl1) ? -l : l);
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}
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/* convert float to int */
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long
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__fixsfsi (float a1)
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{
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double foo = a1;
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return __fixdfsi (foo);
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}
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#else /* EXTFLOAT */
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/* We do not need these routines for coldfire, as it has no extended
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float format. */
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#if !defined (__mcoldfire__)
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/* Primitive extended precision floating point support.
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We assume all numbers are normalized, don't do any rounding, etc. */
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/* Prototypes for the above in case we use them. */
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double __floatunsidf (unsigned long);
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double __floatsidf (long);
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float __floatsisf (long);
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double __extendsfdf2 (float);
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float __truncdfsf2 (double);
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long __fixdfsi (double);
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long __fixsfsi (float);
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int
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__unordxf2(long double a, long double b)
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{
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union long_double_long ldl;
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ldl.ld = a;
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if (EXPX(ldl) == EXPXMASK
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&& ((ldl.l.middle & MANTXMASK) != 0 || ldl.l.lower != 0))
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return 1;
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ldl.ld = b;
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if (EXPX(ldl) == EXPXMASK
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&& ((ldl.l.middle & MANTXMASK) != 0 || ldl.l.lower != 0))
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return 1;
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return 0;
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}
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/* convert double to long double */
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long double
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__extenddfxf2 (double d)
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{
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register union double_long dl;
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register union long_double_long ldl;
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register long exp;
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dl.d = d;
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/*printf ("dfxf in: %g\n", d);*/
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ldl.l.upper = SIGND (dl);
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if ((dl.l.upper & ~SIGNBIT) == 0 && !dl.l.lower)
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{
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ldl.l.middle = 0;
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ldl.l.lower = 0;
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return ldl.ld;
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}
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exp = EXPD (dl) - EXCESSD + EXCESSX;
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ldl.l.upper |= exp << 16;
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ldl.l.middle = HIDDENX;
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/* 31-20: # mantissa bits in ldl.l.middle - # mantissa bits in dl.l.upper */
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ldl.l.middle |= (dl.l.upper & MANTDMASK) << (31 - 20);
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/* 1+20: explicit-integer-bit + # mantissa bits in dl.l.upper */
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ldl.l.middle |= dl.l.lower >> (1 + 20);
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/* 32 - 21: # bits of dl.l.lower in ldl.l.middle */
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ldl.l.lower = dl.l.lower << (32 - 21);
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/*printf ("dfxf out: %s\n", dumpxf (ldl.ld));*/
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return ldl.ld;
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}
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/* convert long double to double */
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double
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__truncxfdf2 (long double ld)
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{
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register long exp;
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register union double_long dl;
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register union long_double_long ldl;
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ldl.ld = ld;
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/*printf ("xfdf in: %s\n", dumpxf (ld));*/
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dl.l.upper = SIGNX (ldl);
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if ((ldl.l.upper & ~SIGNBIT) == 0 && !ldl.l.middle && !ldl.l.lower)
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{
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dl.l.lower = 0;
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return dl.d;
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}
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exp = EXPX (ldl) - EXCESSX + EXCESSD;
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/* ??? quick and dirty: keep `exp' sane */
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if (exp >= EXPDMASK)
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exp = EXPDMASK - 1;
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dl.l.upper |= exp << (32 - (EXPDBITS + 1));
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/* +1-1: add one for sign bit, but take one off for explicit-integer-bit */
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dl.l.upper |= (ldl.l.middle & MANTXMASK) >> (EXPDBITS + 1 - 1);
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dl.l.lower = (ldl.l.middle & MANTXMASK) << (32 - (EXPDBITS + 1 - 1));
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dl.l.lower |= ldl.l.lower >> (EXPDBITS + 1 - 1);
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/*printf ("xfdf out: %g\n", dl.d);*/
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return dl.d;
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}
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/* convert a float to a long double */
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long double
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__extendsfxf2 (float f)
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{
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long double foo = __extenddfxf2 (__extendsfdf2 (f));
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return foo;
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}
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/* convert a long double to a float */
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float
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__truncxfsf2 (long double ld)
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{
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float foo = __truncdfsf2 (__truncxfdf2 (ld));
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return foo;
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}
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/* convert an int to a long double */
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long double
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__floatsixf (long l)
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{
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double foo = __floatsidf (l);
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return foo;
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}
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/* convert an unsigned int to a long double */
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long double
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__floatunsixf (unsigned long l)
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{
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double foo = __floatunsidf (l);
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return foo;
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}
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/* convert a long double to an int */
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long
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__fixxfsi (long double ld)
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{
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long foo = __fixdfsi ((double) ld);
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return foo;
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}
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/* The remaining provide crude math support by working in double precision. */
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long double
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__addxf3 (long double x1, long double x2)
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{
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return (double) x1 + (double) x2;
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}
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long double
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__subxf3 (long double x1, long double x2)
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{
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return (double) x1 - (double) x2;
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}
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long double
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__mulxf3 (long double x1, long double x2)
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{
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return (double) x1 * (double) x2;
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}
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long double
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__divxf3 (long double x1, long double x2)
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{
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return (double) x1 / (double) x2;
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}
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long double
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__negxf2 (long double x1)
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{
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return - (double) x1;
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}
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long
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__cmpxf2 (long double x1, long double x2)
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{
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return __cmpdf2 ((double) x1, (double) x2);
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}
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long
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__eqxf2 (long double x1, long double x2)
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{
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return __cmpdf2 ((double) x1, (double) x2);
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}
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long
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__nexf2 (long double x1, long double x2)
|
||
{
|
||
return __cmpdf2 ((double) x1, (double) x2);
|
||
}
|
||
|
||
long
|
||
__ltxf2 (long double x1, long double x2)
|
||
{
|
||
return __cmpdf2 ((double) x1, (double) x2);
|
||
}
|
||
|
||
long
|
||
__lexf2 (long double x1, long double x2)
|
||
{
|
||
return __cmpdf2 ((double) x1, (double) x2);
|
||
}
|
||
|
||
long
|
||
__gtxf2 (long double x1, long double x2)
|
||
{
|
||
return __cmpdf2 ((double) x1, (double) x2);
|
||
}
|
||
|
||
long
|
||
__gexf2 (long double x1, long double x2)
|
||
{
|
||
return __cmpdf2 ((double) x1, (double) x2);
|
||
}
|
||
|
||
#endif /* !__mcoldfire__ */
|
||
#endif /* EXTFLOAT */
|