Fix long (and long long) to long double, unsigned to long double and unsigned

long (and unsigned long long) to long double conversions.
- Add a parameter that specifies the position of the sign bit to the _QP_TTOQ
  macro, previously it always looked at bit 31.  Pass a negative number to
  disable sign inspection for unsigned types.  This fixes _Qp_xtoq(),
  _Qp_uitoq() and _Qp_uxtoq().
- In the functions __fpu_itof() and __fpu_xtof(), look at the sign bit to
  decide whether we're doing a conversion from an unsigned type.  If so, don't
  negate the mantissa if the integer exceeds the biggest signed number.

PR:		55773
Patch by:	Stephen Paskaluk (based upon)
MFC after:	2 weeks

1 files changed, 16 insertions, 2 deletions

diff --git a/lib/libc/sparc64/fpu/fpu_explode.c b/lib/libc/sparc64/fpu/fpu_explode.c
index 7c1f3eb..09f8908 100644
--- a/lib/libc/sparc64/fpu/fpu_explode.c
+++ b/lib/libc/sparc64/fpu/fpu_explode.c
@@ -101,7 +101,14 @@ __fpu_itof(fp, i)
 	 * fpu_norm()'s handling of `supernormals'; see fpu_subr.c.
 	 */
 	fp->fp_exp = FP_LG;
-	fp->fp_mant[0] = (int)i < 0 ? -i : i;
+	/*
+	 * The sign bit decides whether i should be interpreted as
+	 * a signed or unsigned entity.
+	 */
+	if (fp->fp_sign && (int)i < 0)
+		fp->fp_mant[0] = -i;
+	else
+		fp->fp_mant[0] = i;
 	fp->fp_mant[1] = 0;
 	fp->fp_mant[2] = 0;
 	fp->fp_mant[3] = 0;
@@ -127,7 +134,14 @@ __fpu_xtof(fp, i)
 	 * fpu_norm()'s handling of `supernormals'; see fpu_subr.c.
 	 */
 	fp->fp_exp = FP_LG2;
-	*((int64_t*)fp->fp_mant) = (int64_t)i < 0 ? -i : i;
+	/*
+	 * The sign bit decides whether i should be interpreted as
+	 * a signed or unsigned entity.
+	 */
+	if (fp->fp_sign && (int64_t)i < 0)
+		*((int64_t*)fp->fp_mant) = -i;
+	else
+		*((int64_t*)fp->fp_mant) = i;
 	fp->fp_mant[2] = 0;
 	fp->fp_mant[3] = 0;
 	__fpu_norm(fp);