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* floatformat.c (floatformat_to_double): Correctly handle numbers

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between 1 and 2.  Simplify handling of denormal number.
(main): Test with 1.1.
This commit is contained in:
Andreas Schwab 2012-08-17 21:59:31 +00:00
parent db7618108f
commit e372c21ce5
2 changed files with 20 additions and 24 deletions
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6
libiberty/ChangeLog
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@ -1,3 +1,9 @@
2012-08-17 Andreas Schwab <schwab@linux-m68k.org>
* floatformat.c (floatformat_to_double): Correctly handle numbers
between 1 and 2. Simplify handling of denormal number.
(main): Test with 1.1.
2012-07-31 Mike Frysinger <vapier@gentoo.org> 2012-07-31 Mike Frysinger <vapier@gentoo.org>
* md5.c (md5_finish_ctx): Declare swap_bytes. Assign SWAP() output * md5.c (md5_finish_ctx): Declare swap_bytes. Assign SWAP() output

38
libiberty/floatformat.c
View file

@ -1,5 +1,5 @@
/* IEEE floating point support routines, for GDB, the GNU Debugger. /* IEEE floating point support routines, for GDB, the GNU Debugger.
Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006, 2010 Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006, 2010, 2012
Free Software Foundation, Inc. Free Software Foundation, Inc.
This file is part of GDB. This file is part of GDB.
@ -463,7 +463,6 @@ floatformat_to_double (const struct floatformat *fmt,
unsigned long mant; unsigned long mant;
unsigned int mant_bits, mant_off; unsigned int mant_bits, mant_off;
int mant_bits_left; int mant_bits_left;
int special_exponent; /* It's a NaN, denorm or zero */
/* Split values are not handled specially, since the top half has /* Split values are not handled specially, since the top half has
the correctly rounded double value (in the only supported case of the correctly rounded double value (in the only supported case of
@ -503,20 +502,20 @@ floatformat_to_double (const struct floatformat *fmt,
mant_off = fmt->man_start; mant_off = fmt->man_start;
dto = 0.0; dto = 0.0;
special_exponent = exponent == 0 || (unsigned long) exponent == fmt->exp_nan;
/* Don't bias zero's, denorms or NaNs. */
if (!special_exponent)
exponent -= fmt->exp_bias;
/* Build the result algebraically. Might go infinite, underflow, etc; /* Build the result algebraically. Might go infinite, underflow, etc;
who cares. */ who cares. */
/* If this format uses a hidden bit, explicitly add it in now. Otherwise, /* For denorms use minimum exponent. */
increment the exponent by one to account for the integer bit. */ if (exponent == 0)
exponent = 1 - fmt->exp_bias;
if (!special_exponent) else
{ {
exponent -= fmt->exp_bias;
/* If this format uses a hidden bit, explicitly add it in now.
Otherwise, increment the exponent by one to account for the
integer bit. */
if (fmt->intbit == floatformat_intbit_no) if (fmt->intbit == floatformat_intbit_no)
dto = ldexp (1.0, exponent); dto = ldexp (1.0, exponent);
else else
@ -530,18 +529,8 @@ floatformat_to_double (const struct floatformat *fmt,
mant = get_field (ufrom, fmt->byteorder, fmt->totalsize, mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
mant_off, mant_bits); mant_off, mant_bits);
/* Handle denormalized numbers. FIXME: What should we do for dto += ldexp ((double) mant, exponent - mant_bits);
non-IEEE formats? */ exponent -= mant_bits;
if (special_exponent && exponent == 0 && mant != 0)
dto += ldexp ((double)mant,
(- fmt->exp_bias
- mant_bits
- (mant_off - fmt->man_start)
+ 1));
else
dto += ldexp ((double)mant, exponent - mant_bits);
if (exponent != 0)
exponent -= mant_bits;
mant_off += mant_bits; mant_off += mant_bits;
mant_bits_left -= mant_bits; mant_bits_left -= mant_bits;
} }
@ -756,6 +745,7 @@ main (void)
{ {
ieee_test (0.0); ieee_test (0.0);
ieee_test (0.5); ieee_test (0.5);
ieee_test (1.1);
ieee_test (256.0); ieee_test (256.0);
ieee_test (0.12345); ieee_test (0.12345);
ieee_test (234235.78907234); ieee_test (234235.78907234);