MIPS: soft-fp NaN representation corrections

[BZ #15442] This adds support for the inverse interpretation of the
quiet bit of IEEE 754 floating-point NaN data that some processors
use.  This includes in particular MIPS architecture processors; the
payload used for the canonical qNaN encoding is updated accordingly
so as not to interfere with the quiet bit.

ChangeLog

@@ -1,3 +1,24 @@
+2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	[BZ #15442]
+	* soft-fp/op-common.h (_FP_FRAC_SNANP): New macro.
+	(_FP_FRAC_SNANP_SEMIRAW): Likewise.
+	(_FP_UNPACK_CANONICAL): Use _FP_FRAC_SNANP.
+	(_FP_CHECK_SIGNAN_SEMIRAW): Use _FP_FRAC_SNANP_SEMIRAW.
+	(_FP_SETQNAN): New macro.
+	(_FP_SETQNAN_SEMIRAW): Likewise.
+	(_FP_PACK_SEMIRAW): Use _FP_SETQNAN.
+	(_FP_PACK_CANONICAL): Use _FP_SETQNAN.
+	(_FP_ISSIGNAN): Use _FP_FRAC_SNANP.
+	(FP_EXTEND): Use _FP_FRAC_SNANP.
+	(FP_TRUNC): Use _FP_SETQNAN_SEMIRAW.
+	* soft-fp/testit.c (gen_special_double): Take _FP_QNANNEGATEDP
+	into account.
+	* sysdeps/sparc/sparc32/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP):
+	New macro.
+	* sysdeps/sparc/sparc64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP):
+	Likewise.
+
 2013-05-16  Joseph Myers  <joseph@codesourcery.com>
 
 	* math/libm-test.inc (atanh_test_data): Use ERRNO_ERANGE together

NEWS

@@ -17,7 +17,7 @@ Version 2.18
   15086, 15160, 15214, 15221, 15232, 15234, 15283, 15285, 15287, 15304,
   15305, 15307, 15309, 15327, 15330, 15335, 15336, 15337, 15342, 15346,
   15359, 15361, 15366, 15380, 15394, 15395, 15405, 15406, 15409, 15416,
-  15418, 15419, 15423, 15426, 15429, 15448.
+  15418, 15419, 15423, 15426, 15429, 15442, 15448.
 
 * CVE-2013-0242 Buffer overrun in regexp matcher has been fixed (Bugzilla
   #15078).

ports/ChangeLog.aarch64

@@ -1,3 +1,9 @@
+2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	[BZ #15442]
+	* sysdeps/aarch64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
+	macro.
+
 2013-05-12  Marcus Shawcroft  <marcus.shawcroft@linaro.org>
 
 	* sysdeps/unix/sysv/linux/aarch64/clone.S (__clone):

ports/ChangeLog.alpha

@@ -1,3 +1,9 @@
+2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	[BZ #15442]
+	* sysdeps/alpha/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
+	macro.
+
 2013-03-06  Andreas Jaeger  <aj@suse.de>
 
 	* sysdeps/unix/sysv/linux/alpha/bits/mman.h (MAP_HUGE_MASK)

ports/ChangeLog.mips

@@ -1,3 +1,17 @@
+2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	[BZ #15442]
+	* sysdeps/mips/mips64/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP):
+	New macro.
+	(_FP_NANFRAC_S): Don't set the quiet bit.
+	(_FP_NANFRAC_D): Likewise.
+	(_FP_NANFRAC_Q): Likewise.
+	* sysdeps/mips/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
+	macro.
+	(_FP_NANFRAC_S): Don't set the quiet bit.
+	(_FP_NANFRAC_D): Likewise.
+	(_FP_NANFRAC_Q): Likewise.
+
 2013-05-16  Ryan S. Arnold  <rsa@linux.vnet.ibm.com>
 
 	* sysdeps/unix/sysv/linux/mips/kernel_rt_sigframe.h: Add missing

ports/ChangeLog.powerpc

@@ -1,3 +1,9 @@
+2013-05-16  Maciej W. Rozycki  <macro@codesourcery.com>
+
+	[BZ #15442]
+	* sysdeps/powerpc/soft-fp/sfp-machine.h (_FP_QNANNEGATEDP): New
+	macro.
+
 2013-02-28  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #13550]

ports/sysdeps/aarch64/soft-fp/sfp-machine.h

@@ -25,6 +25,8 @@
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 0
+
 /* From my experiments it seems X is chosen unless one of the
    NaNs is sNaN,  in which case the result is NANSIGN/NANFRAC.  */
 #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP)			\

ports/sysdeps/alpha/soft-fp/sfp-machine.h

@@ -46,6 +46,7 @@
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 0
 
 /* Alpha Architecture Handbook, 4.7.10.4 sez that we should prefer any
    type of NaN in Fb, then Fa.  */

ports/sysdeps/mips/mips64/soft-fp/sfp-machine.h

@@ -17,14 +17,16 @@
 #define _FP_DIV_MEAT_D(R,X,Y)	_FP_DIV_MEAT_1_udiv_norm(D,R,X,Y)
 #define _FP_DIV_MEAT_Q(R,X,Y)	_FP_DIV_MEAT_2_udiv(Q,R,X,Y)
 
-#define _FP_NANFRAC_S		((_FP_QNANBIT_S << 1) - 1)
+#define _FP_NANFRAC_S		(_FP_QNANBIT_S - 1)
-#define _FP_NANFRAC_D		((_FP_QNANBIT_D << 1) - 1)
+#define _FP_NANFRAC_D		(_FP_QNANBIT_D - 1)
-#define _FP_NANFRAC_Q		((_FP_QNANBIT_Q << 1) - 1), -1
+#define _FP_NANFRAC_Q		(_FP_QNANBIT_Q - 1), -1
 #define _FP_NANSIGN_S		0
 #define _FP_NANSIGN_D		0
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 1
+
 /* From my experiments it seems X is chosen unless one of the
    NaNs is sNaN,  in which case the result is NANSIGN/NANFRAC.  */
 #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP)			\

ports/sysdeps/mips/soft-fp/sfp-machine.h

@@ -14,14 +14,16 @@
 #define _FP_DIV_MEAT_D(R,X,Y)	_FP_DIV_MEAT_2_udiv(D,R,X,Y)
 #define _FP_DIV_MEAT_Q(R,X,Y)	_FP_DIV_MEAT_4_udiv(Q,R,X,Y)
 
-#define _FP_NANFRAC_S		((_FP_QNANBIT_S << 1) - 1)
+#define _FP_NANFRAC_S		(_FP_QNANBIT_S - 1)
-#define _FP_NANFRAC_D		((_FP_QNANBIT_D << 1) - 1), -1
+#define _FP_NANFRAC_D		(_FP_QNANBIT_D - 1), -1
-#define _FP_NANFRAC_Q		((_FP_QNANBIT_Q << 1) - 1), -1, -1, -1
+#define _FP_NANFRAC_Q		(_FP_QNANBIT_Q - 1), -1, -1, -1
 #define _FP_NANSIGN_S		0
 #define _FP_NANSIGN_D		0
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 1
+
 /* From my experiments it seems X is chosen unless one of the
    NaNs is sNaN,  in which case the result is NANSIGN/NANFRAC.  */
 #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP)			\

ports/sysdeps/powerpc/soft-fp/sfp-machine.h

@@ -22,6 +22,7 @@
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 0
 
 /* Someone please check this.  */
 #define _FP_CHOOSENAN(fs, wc, R, X, Y, OP)			\

soft-fp/op-common.h

@@ -35,6 +35,16 @@
   _FP_I_TYPE X##_e;				\
   _FP_FRAC_DECL_##wc(X)
 
+/* Test whether the qNaN bit denotes a signaling NaN.  */
+#define _FP_FRAC_SNANP(fs, X)						\
+  ((_FP_QNANNEGATEDP)							\
+   ? (_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs)			\
+   : !(_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs))
+#define _FP_FRAC_SNANP_SEMIRAW(fs, X)					\
+  ((_FP_QNANNEGATEDP)							\
+   ? (_FP_FRAC_HIGH_##fs(X) & _FP_QNANBIT_SH_##fs)			\
+   : !(_FP_FRAC_HIGH_##fs(X) & _FP_QNANBIT_SH_##fs))
+
 /*
  * Finish truely unpacking a native fp value by classifying the kind
  * of fp value and normalizing both the exponent and the fraction.
@@ -74,7 +84,7 @@ do {									\
       {									\
 	X##_c = FP_CLS_NAN;						\
 	/* Check for signaling NaN */					\
-	if (!(_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs))		\
+	if (_FP_FRAC_SNANP(fs, X))					\
 	  FP_SET_EXCEPTION(FP_EX_INVALID);				\
       }									\
     break;								\
@@ -112,7 +122,7 @@ do {							\
 do {								\
   if (X##_e == _FP_EXPMAX_##fs					\
       && !_FP_FRAC_ZEROP_##wc(X)				\
-      && !(_FP_FRAC_HIGH_##fs(X) & _FP_QNANBIT_SH_##fs))	\
+      && _FP_FRAC_SNANP_SEMIRAW(fs, X))				\
     FP_SET_EXCEPTION(FP_EX_INVALID);				\
 } while (0)
 
@@ -127,6 +137,39 @@ do {									\
   _FP_FRAC_SLL_##wc(R, _FP_WORKBITS);					\
 } while (0)
 
+/* Make the fractional part a quiet NaN, preserving the payload
+   if possible, otherwise make it the canonical quiet NaN and set
+   the sign bit accordingly.  */
+#define _FP_SETQNAN(fs, wc, X)						\
+do {									\
+  if (_FP_QNANNEGATEDP)							\
+    {									\
+      _FP_FRAC_HIGH_RAW_##fs(X) &= _FP_QNANBIT_##fs - 1;		\
+      if (_FP_FRAC_ZEROP_##wc(X))					\
+	{								\
+	  X##_s = _FP_NANSIGN_##fs;					\
+	  _FP_FRAC_SET_##wc(X, _FP_NANFRAC_##fs);			\
+	}								\
+    }									\
+  else									\
+    _FP_FRAC_HIGH_RAW_##fs(X) |= _FP_QNANBIT_##fs;			\
+} while (0)
+#define _FP_SETQNAN_SEMIRAW(fs, wc, X)					\
+do {									\
+  if (_FP_QNANNEGATEDP)							\
+    {									\
+      _FP_FRAC_HIGH_##fs(X) &= _FP_QNANBIT_SH_##fs - 1;			\
+      if (_FP_FRAC_ZEROP_##wc(X))					\
+	{								\
+	  X##_s = _FP_NANSIGN_##fs;					\
+	  _FP_FRAC_SET_##wc(X, _FP_NANFRAC_##fs);			\
+	  _FP_FRAC_SLL_##wc(X, _FP_WORKBITS);				\
+	}								\
+    }									\
+  else									\
+    _FP_FRAC_HIGH_##fs(X) |= _FP_QNANBIT_SH_##fs;			\
+} while (0)
+
 /* Test whether a biased exponent is normal (not zero or maximum).  */
 #define _FP_EXP_NORMAL(fs, wc, X)	(((X##_e + 1) & _FP_EXPMAX_##fs) > 1)
 
@@ -159,7 +202,7 @@ do {								\
 	  X##_s = _FP_NANSIGN_##fs;				\
 	}							\
       else							\
-	_FP_FRAC_HIGH_RAW_##fs(X) |= _FP_QNANBIT_##fs;		\
+	_FP_SETQNAN(fs, wc, X);					\
     }								\
 } while (0)
 
@@ -273,7 +316,7 @@ do {								\
 	X##_s = _FP_NANSIGN_##fs;				\
       }								\
     else							\
-      _FP_FRAC_HIGH_RAW_##fs(X) |= _FP_QNANBIT_##fs;		\
+      _FP_SETQNAN(fs, wc, X);					\
     break;							\
   }								\
 } while (0)
@@ -287,7 +330,7 @@ do {								\
   if (X##_e == _FP_EXPMAX_##fs)					\
     {								\
       if (!_FP_FRAC_ZEROP_##wc(X)				\
-	  && !(_FP_FRAC_HIGH_RAW_##fs(X) & _FP_QNANBIT_##fs))	\
+	  && _FP_FRAC_SNANP(fs, X))				\
 	__ret = 1;						\
     }								\
   __ret;							\
@@ -1199,7 +1242,7 @@ do {									 \
 	  D##_e = _FP_EXPMAX_##dfs;					 \
 	  if (!_FP_FRAC_ZEROP_##swc(S))					 \
 	    {								 \
-	      if (!(_FP_FRAC_HIGH_RAW_##sfs(S) & _FP_QNANBIT_##sfs))	 \
+	      if (_FP_FRAC_SNANP(sfs, S))				 \
 		FP_SET_EXCEPTION(FP_EX_INVALID);			 \
 	      _FP_FRAC_SLL_##dwc(D, (_FP_FRACBITS_##dfs			 \
 				     - _FP_FRACBITS_##sfs));		 \
@@ -1286,7 +1329,7 @@ do {									     \
 	      /* Semi-raw NaN must have all workbits cleared.  */	     \
 	      _FP_FRAC_LOW_##dwc(D)					     \
 		&= ~(_FP_W_TYPE) ((1 << _FP_WORKBITS) - 1);		     \
-	      _FP_FRAC_HIGH_##dfs(D) |= _FP_QNANBIT_SH_##dfs;		     \
+	      _FP_SETQNAN_SEMIRAW(dfs, dwc, D);				     \
 	    }								     \
 	}								     \
     }									     \

soft-fp/testit.c

@@ -200,17 +200,17 @@ double gen_special_double(int i)
       case 0:
 	X_c = FP_CLS_NAN;
 #if _FP_W_TYPE_SIZE < _FP_FRACBITS_D
-	__FP_FRAC_SET_2(X, _FP_QNANBIT_D, 0x1234);
+	__FP_FRAC_SET_2(X, _FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D, 0x1234);
 #else
-	_FP_FRAC_SET_1(X, _FP_QNANBIT_D | 0x1234);
+	_FP_FRAC_SET_1(X, (_FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D) | 0x1234);
 #endif
 	break;
       case 2:
 	X_c = FP_CLS_NAN;
 #if _FP_W_TYPE_SIZE < _FP_FRACBITS_D
-	__FP_FRAC_SET_2(X, _FP_QNANBIT_D, 0x1);
+	__FP_FRAC_SET_2(X, _FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D, 0x1);
 #else
-	_FP_FRAC_SET_1(X, _FP_QNANBIT_D | 0x1);
+	_FP_FRAC_SET_1(X, (_FP_QNANNEGATEDP ? 0 : _FP_QNANBIT_D) | 0x1);
 #endif
 	break;
       case 4:

sysdeps/sparc/sparc32/soft-fp/sfp-machine.h

@@ -47,6 +47,7 @@
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 0
 
 /* If one NaN is signaling and the other is not,
  * we choose that one, otherwise we choose X.

sysdeps/sparc/sparc64/soft-fp/sfp-machine.h

@@ -60,6 +60,7 @@ do {								\
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
+#define _FP_QNANNEGATEDP 0
 
 /* If one NaN is signaling and the other is not,
  * we choose that one, otherwise we choose Y.