Fix conversions to long double on sparc64

Bug exposed by erratic sqlite3 behavior used in ports/devel/proj,
as pointed out by landry@.  Richard Hipps (SQLite) pointed at the
culprit (_Qp_div), many thanks.

Adapted from FreeBSD revision 146673 by Stephen Paskaluk and
stefanf@FreeBSD.  FreeBSD commit message:

"""
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.
"""

ok deraadt@

2 files changed, 12 insertions, 12 deletions

diff --git a/lib/libc/arch/sparc64/fpu/fpu_explode.c b/lib/libc/arch/sparc64/fpu/fpu_explode.c
index e16eff95ecd..8ee93048645 100644
--- a/lib/libc/arch/sparc64/fpu/fpu_explode.c
+++ b/lib/libc/arch/sparc64/fpu/fpu_explode.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpu_explode.c,v 1.9 2019/03/15 05:42:38 kevlo Exp $	*/
+/*	$OpenBSD: fpu_explode.c,v 1.10 2019/06/21 17:00:58 jca Exp $	*/
 
 /*
  * Copyright (c) 1992, 1993
@@ -99,7 +99,7 @@ __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;
+	fp->fp_mant[0] = (fp->fp_sign && (int)i < 0) ? -i : i;
 	fp->fp_mant[1] = 0;
 	fp->fp_mant[2] = 0;
 	fp->fp_mant[3] = 0;
@@ -151,7 +151,7 @@ __fpu_xtof(fp, i)
 	 * fpu_norm()'s handling of `supernormals'; see fpu_subr.c.
 	 */
 	fp->fp_exp = FP_LG2;
-	i = ((int64_t)i < 0) ? -i : i;
+	i = (fp->fp_sign && (int64_t)i < 0) ? -i : i;
 	fp->fp_mant[0] = (i >> 32) & 0xffffffff;
 	fp->fp_mant[1] = (i >> 0)  & 0xffffffff;
 	fp->fp_mant[2] = 0;
diff --git a/lib/libc/arch/sparc64/fpu/fpu_qp.c b/lib/libc/arch/sparc64/fpu/fpu_qp.c
index 8c7a088b007..c0821b2b487 100644
--- a/lib/libc/arch/sparc64/fpu/fpu_qp.c
+++ b/lib/libc/arch/sparc64/fpu/fpu_qp.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: fpu_qp.c,v 1.7 2019/03/15 05:42:38 kevlo Exp $	*/
+/*	$OpenBSD: fpu_qp.c,v 1.8 2019/06/21 17:00:58 jca Exp $	*/
 
 /*-
  * Copyright (c) 2002 Jake Burkholder.
@@ -52,7 +52,7 @@ _Qp_ ## op(u_int *c, u_int *a, u_int *b) \
 } \
 DEF_STRONG(_Qp_ ## op);
 
-#define	_QP_TTOQ(qname, fname, ntype, atype, signed, ...) \
+#define	_QP_TTOQ(qname, fname, ntype, signpos, atype, ...) \
 void _Qp_ ## qname ## toq(u_int *c, ntype n); \
 PROTO_NORMAL(_Qp_ ## qname ## toq); \
 void \
@@ -62,7 +62,7 @@ _Qp_ ## qname ## toq(u_int *c, ntype n) \
 	atype *a; \
 	__asm volatile("stx %%fsr, %0" : "=m" (fe.fe_fsr) :); \
 	a = (atype *)&n; \
-	fe.fe_f1.fp_sign = signed ? a[0] >> 31 : 0; \
+	fe.fe_f1.fp_sign = (signpos >= 0) ? a[0] >> signpos : 0; \
 	fe.fe_f1.fp_sticky = 0; \
 	fe.fe_f1.fp_class = __fpu_ ## fname ## tof(&fe.fe_f1, __VA_ARGS__); \
 	c[0] = __fpu_ftoq(&fe, &fe.fe_f1, c); \
@@ -176,12 +176,12 @@ _QP_OP(div)
 _QP_OP(mul)
 _QP_OP(sub)
 
-_QP_TTOQ(d,	d,	double,	u_int,	1, a[0], a[1])
-_QP_TTOQ(i,	i,	int,	u_int,	1, a[0])
-_QP_TTOQ(s,	s,	float,	u_int,	1, a[0])
-_QP_TTOQ(x,	x,	long,	u_long,	1, a[0])
-_QP_TTOQ(ui,	ui,	u_int,	u_int,	0, a[0])
-_QP_TTOQ(ux,	ux,	u_long,	u_long,	0, a[0])
+_QP_TTOQ(d,	d,	double,	31,	u_int,	a[0], a[1])
+_QP_TTOQ(i,	i,	int,	31,	u_int,	a[0])
+_QP_TTOQ(s,	s,	float,	31,	u_int,	a[0])
+_QP_TTOQ(x,	x,	long,	63,	u_long,	a[0])
+_QP_TTOQ(ui,	ui,	u_int,	-1,	u_int,	a[0])
+_QP_TTOQ(ux,	ux,	u_long,	-1,	u_long,	a[0])
 
 _QP_QTOT4(d,	d,	double,	a)
 _QP_QTOT3(i,	i,	int)