Take number 2. I moved the adjustment to the exponent into __pformat_xldouble.
>From b5a399f21cb15f5d3a38b312c7889adede225ff6 Mon Sep 17 00:00:00 2001
From: Patrick Northon <[email protected]>
Date: Tue, 7 Sep 2021 12:11:20 -0400
Subject: [PATCH] Fix exponent when formatting long double in hexadecimal.
Some denormalized values were emited incorrectly due to incorrect conditional adjustement of the exponent.
---
mingw-w64-crt/stdio/mingw_pformat.c | 20 +++-----------------
1 file changed, 3 insertions(+), 17 deletions(-)
diff --git a/mingw-w64-crt/stdio/mingw_pformat.c b/mingw-w64-crt/stdio/mingw_pformat.c
index b2e1af6ec..c38847442 100644
--- a/mingw-w64-crt/stdio/mingw_pformat.c
+++ b/mingw-w64-crt/stdio/mingw_pformat.c
@@ -2045,7 +2045,7 @@ void __pformat_emit_xfloat( __pformat_fpreg_t value, __pformat_t *stream )
* of this is equivalent to an increment of the exponent. We will
* discard a whole digit to match glibc's behavior.
*/
- value.__pformat_fpreg_exponent++;
+ value.__pformat_fpreg_exponent += 4;
value.__pformat_fpreg_mantissa >>= 3;
}
@@ -2086,20 +2086,6 @@ void __pformat_emit_xfloat( __pformat_fpreg_t value, __pformat_t *stream )
*/
*p++ = '.';
}
-
- /* If the most significant hexadecimal digit of the encoded
- * output value is greater than one, then the indicated value
- * will appear too large, by an additional binary exponent
- * corresponding to the number of higher order bit positions
- * which it occupies...
- */
- while( value.__pformat_fpreg_mantissa > 1 )
- {
- /* so reduce the exponent value to compensate...
- */
- value.__pformat_fpreg_exponent--;
- value.__pformat_fpreg_mantissa >>= 1;
- }
}
else if( stream->precision > 0 )
@@ -2305,14 +2291,14 @@ void __pformat_xldouble( long double x, __pformat_t *stream )
{
/* ...this mantissa represents a subnormal value.
*/
- z.__pformat_fpreg_exponent = -0x3FFF - 2;
+ z.__pformat_fpreg_exponent = 1 - 0x3FFF - 3;
}
}
else
/* This argument represents a non-zero normal number;
* eliminate the bias from the exponent...
*/
- z.__pformat_fpreg_exponent -= 0x3FFF;
+ z.__pformat_fpreg_exponent -= 0x3FFF + 3;
/* Finally, hand the adjusted representation off to the
* generalised hexadecimal floating point format handler...
--
2.33.0
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