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fix printf precision specifier for hex floats on non-ld80 archs

the code to perform rounding to the desired precision wrongly assumed
the long double mantissa was an integral number of nibbles (hex
digits) in length. this is true for 80-bit extended precision (64-bit
mantissa) but not for double (53) or quad (113).

scale the rounding value by 1<<(LDBL_MANT_DIG%4) to compensate.
Rich Felker 6 years ago
parent
commit
cfa0a54c08
1 changed files with 1 additions and 0 deletions
  1. 1 0
      src/stdio/vfprintf.c

+ 1 - 0
src/stdio/vfprintf.c

@@ -220,6 +220,7 @@ static int fmt_fp(FILE *f, long double y, int w, int p, int fl, int t)
 		else re=LDBL_MANT_DIG/4-1-p;
 
 		if (re) {
+			round *= 1<<(LDBL_MANT_DIG%4);
 			while (re--) round*=16;
 			if (*prefix=='-') {
 				y=-y;