floatformat.c (floatformat_to_double): Correctly handle numbers between 1 and 2.

* floatformat.c (floatformat_to_double): Correctly handle numbers
between 1 and 2.  Simplify handling of denormal number.
(main): Test with 1.1.

From-SVN: r190493
This commit is contained in:
Andreas Schwab 2012-08-17 21:56:48 +00:00 committed by Andreas Schwab
parent e327d1a362
commit c9ac76ae53
2 changed files with 20 additions and 24 deletions

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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>
* md5.c (md5_finish_ctx): Declare swap_bytes. Assign SWAP() output

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@ -1,5 +1,5 @@
/* 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.
This file is part of GDB.
@ -463,7 +463,6 @@ floatformat_to_double (const struct floatformat *fmt,
unsigned long mant;
unsigned int mant_bits, mant_off;
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
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;
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;
who cares. */
/* 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 (!special_exponent)
/* For denorms use minimum exponent. */
if (exponent == 0)
exponent = 1 - fmt->exp_bias;
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)
dto = ldexp (1.0, exponent);
else
@ -530,18 +529,8 @@ floatformat_to_double (const struct floatformat *fmt,
mant = get_field (ufrom, fmt->byteorder, fmt->totalsize,
mant_off, mant_bits);
/* Handle denormalized numbers. FIXME: What should we do for
non-IEEE formats? */
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;
dto += ldexp ((double) mant, exponent - mant_bits);
exponent -= mant_bits;
mant_off += mant_bits;
mant_bits_left -= mant_bits;
}
@ -756,6 +745,7 @@ main (void)
{
ieee_test (0.0);
ieee_test (0.5);
ieee_test (1.1);
ieee_test (256.0);
ieee_test (0.12345);
ieee_test (234235.78907234);