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.

diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
index 50fb55c16149ed1166ff86077acf650f1efe721a..5e7be717333638bbef041a676199814811712925 100644 (file)
--- a/src/stdio/vfprintf.c
+++ b/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;