Fix ilogb exception and errno (bug 6794)

[BZ #6794]
Following Joseph comments about bug 6794, here is a proposed fix. It turned out
to be a large fix mainly because I had to move some file along to follow libm
files/names conventions.

Basically I have added wrappers (w_ilogb.c, w_ilogbf.c, w_ilogbl.c) that now calls
the symbol '__ieee754_ilogb'. The wrappers checks for '__ieee754_ilogb' output and
set the errno and raise exceptions as expected.

The '__ieee754_ilogb' is implemented in sysdeps. I have moved the 's_ilogb[f|l]' files
to e_ilogb[f|l] and renamed the '__ilogb[f|l]' to '__ieee754_ilogb[f|l]'.

I also found out a bug in i386 and x86-64 assembly coded ilogb implementation where
it raises a FE_DIVBYZERO when argument is '0.0'. I corrected this issue as well.

Finally I added the errno and FE_INVALID tests for 0.0, NaN and +-InF argument. Tested
on i386, x86-64, ppc32 and ppc64.

10 files changed, 46 insertions, 23 deletions

diff --git a/sysdeps/generic/math_private.h b/sysdeps/generic/math_private.h
index e217224..5267ec3 100644
--- a/sysdeps/generic/math_private.h
+++ b/sysdeps/generic/math_private.h
@@ -213,6 +213,7 @@ extern double __ieee754_yn (int,double);
 extern double __ieee754_remainder (double,double);
 extern int32_t __ieee754_rem_pio2 (double,double*);
 extern double __ieee754_scalb (double,double);
+extern int __ieee754_ilogb (double);
 
 /* fdlibm kernel function */
 extern double __kernel_standard (double,double,int);
@@ -260,6 +261,7 @@ extern float __ieee754_ynf (int,float);
 extern float __ieee754_remainderf (float,float);
 extern int32_t __ieee754_rem_pio2f (float,float*);
 extern float __ieee754_scalbf (float,float);
+extern int __ieee754_ilogbf (float);
 
 
 /* float versions of fdlibm kernel functions */
@@ -305,6 +307,7 @@ extern long double __ieee754_ynl (int,long double);
 extern long double __ieee754_remainderl (long double,long double);
 extern int   __ieee754_rem_pio2l (long double,long double*);
 extern long double __ieee754_scalbl (long double,long double);
+extern int   __ieee754_ilogbl (long double);
 
 /* long double versions of fdlibm kernel functions */
 extern long double __kernel_sinl (long double,long double,int);
diff --git a/sysdeps/i386/fpu/s_ilogb.S b/sysdeps/i386/fpu/e_ilogb.S
index 0cf1ad7..4fb6350 100644
--- a/sysdeps/i386/fpu/s_ilogb.S
+++ b/sysdeps/i386/fpu/e_ilogb.S
@@ -7,7 +7,7 @@
 
 RCSID("$NetBSD: s_ilogb.S,v 1.5 1995/10/12 15:53:09 jtc Exp $")
 
-ENTRY(__ilogb)
+ENTRY(__ieee754_ilogb)
 	fldl	4(%esp)
 /* I added the following ugly construct because ilogb(+-Inf) is
    required to return INT_MAX in ISO C99.
@@ -18,6 +18,8 @@ ENTRY(__ilogb)
 	andb    %ah, %dh
 	cmpb    $0x05, %dh
 	je      1f		/* Is +-Inf, jump.  */
+	cmpb    $0x40, %dh
+	je      2f		/* Is +-0, jump.  */
 
 	fxtract
 	pushl	%eax
@@ -34,5 +36,8 @@ ENTRY(__ilogb)
 1:	fstp	%st
 	movl	$0x7fffffff, %eax
 	ret
-END (__ilogb)
-weak_alias (__ilogb, ilogb)
+2:	fstp	%st
+	movl	$0x80000000, %eax	/* FP_ILOGB0  */
+	ret
+END (__ieee754_ilogb)
+weak_alias (__ieee754_ilogb, __ilogb_finite)
diff --git a/sysdeps/i386/fpu/s_ilogbf.S b/sysdeps/i386/fpu/e_ilogbf.S
index 99e53ed..fbb50be 100644
--- a/sysdeps/i386/fpu/s_ilogbf.S
+++ b/sysdeps/i386/fpu/e_ilogbf.S
@@ -7,7 +7,7 @@
 
 RCSID("$NetBSD: s_ilogbf.S,v 1.4 1995/10/22 20:32:43 pk Exp $")
 
-ENTRY(__ilogbf)
+ENTRY(__ieee754_ilogbf)
 	flds	4(%esp)
 /* I added the following ugly construct because ilogb(+-Inf) is
    required to return INT_MAX in ISO C99.
@@ -18,6 +18,8 @@ ENTRY(__ilogbf)
 	andb    %ah, %dh
 	cmpb    $0x05, %dh
 	je      1f		/* Is +-Inf, jump.  */
+	cmpb    $0x40, %dh
+	je      2f		/* Is +-0, jump.  */
 
 	fxtract
 	pushl	%eax
@@ -34,5 +36,8 @@ ENTRY(__ilogbf)
 1:	fstp	%st
 	movl	$0x7fffffff, %eax
 	ret
-END (__ilogbf)
-weak_alias (__ilogbf, ilogbf)
+2:	fstp	%st
+	movl	$0x80000000, %eax	/* FP_ILOGB0  */
+	ret
+END (__ieee754_ilogbf)
+weak_alias (__ieee754_ilogbf, __ilogbf_finite)
diff --git a/sysdeps/i386/fpu/s_ilogbl.S b/sysdeps/i386/fpu/e_ilogbl.S
index 1f559b3..6e2be9a 100644
--- a/sysdeps/i386/fpu/s_ilogbl.S
+++ b/sysdeps/i386/fpu/e_ilogbl.S
@@ -8,7 +8,7 @@
 
 RCSID("$NetBSD: $")
 
-ENTRY(__ilogbl)
+ENTRY(__ieee754_ilogbl)
 	fldt	4(%esp)
 /* I added the following ugly construct because ilogb(+-Inf) is
    required to return INT_MAX in ISO C99.
@@ -19,6 +19,8 @@ ENTRY(__ilogbl)
 	andb    %ah, %dh
 	cmpb    $0x05, %dh
 	je      1f		/* Is +-Inf, jump.  */
+	cmpb    $0x40, %dh
+	je      2f		/* Is +-0, jump.  */
 
 	fxtract
 	pushl	%eax
@@ -35,5 +37,8 @@ ENTRY(__ilogbl)
 1:	fstp	%st
 	movl	$0x7fffffff, %eax
 	ret
-END (__ilogbl)
-weak_alias (__ilogbl, ilogbl)
+2:	fstp	%st
+	movl	$0x80000000, %eax	/* FP_ILOGB0  */
+	ret
+END (__ieee754_ilogbl)
+weak_alias (__ieee754_ilogbl, __ilogbl_finite)
diff --git a/sysdeps/ieee754/dbl-64/s_ilogb.c b/sysdeps/ieee754/dbl-64/e_ilogb.c
index 05c66d7..7772880 100644
--- a/sysdeps/ieee754/dbl-64/s_ilogb.c
+++ b/sysdeps/ieee754/dbl-64/e_ilogb.c
@@ -25,7 +25,7 @@ static char rcsid[] = "$NetBSD: s_ilogb.c,v 1.9 1995/05/10 20:47:28 jtc Exp $";
 #include <math.h>
 #include <math_private.h>
 
-int __ilogb(double x)
+int __ieee754_ilogb(double x)
 {
 	int32_t hx,lx,ix;
 
@@ -52,8 +52,4 @@ int __ilogb(double x)
 	}
 	return FP_ILOGBNAN;
 }
-weak_alias (__ilogb, ilogb)
-#ifdef NO_LONG_DOUBLE
-strong_alias (__ilogb, __ilogbl)
-weak_alias (__ilogb, ilogbl)
-#endif
+strong_alias (__ieee754_ilogb, __ilogb_finite)
diff --git a/sysdeps/ieee754/flt-32/s_ilogbf.c b/sysdeps/ieee754/flt-32/e_ilogbf.c
index 21f9cd9..c7441a8 100644
--- a/sysdeps/ieee754/flt-32/s_ilogbf.c
+++ b/sysdeps/ieee754/flt-32/e_ilogbf.c
@@ -21,7 +21,7 @@ static char rcsid[] = "$NetBSD: s_ilogbf.c,v 1.4 1995/05/10 20:47:31 jtc Exp $";
 #include <math.h>
 #include <math_private.h>
 
-int __ilogbf(float x)
+int __ieee754_ilogbf(float x)
 {
 	int32_t hx,ix;
 
@@ -42,4 +42,4 @@ int __ilogbf(float x)
 	}
 	return FP_ILOGBNAN;
 }
-weak_alias (__ilogbf, ilogbf)
+strong_alias (__ieee754_ilogbf, __ilogbf_finite)
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_ilogbl.c b/sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c
index a6f0e1e..55f87ed 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_ilogbl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/e_ilogbl.c
@@ -29,7 +29,7 @@ static char rcsid[] = "$NetBSD: $";
 #include <math_private.h>
 #include <math_ldbl_opt.h>
 
-int __ilogbl(long double x)
+int __ieee754_ilogbl(long double x)
 {
 	int64_t hx,lx;
 	int ix;
@@ -55,4 +55,3 @@ int __ilogbl(long double x)
 	}
 	return FP_ILOGBNAN;
 }
-long_double_symbol (libm, __ilogbl, ilogbl);
diff --git a/sysdeps/ieee754/ldbl-opt/s_ilogb.c b/sysdeps/ieee754/ldbl-opt/w_ilogb.c
index 3a6ccbd..f518087 100644
--- a/sysdeps/ieee754/ldbl-opt/s_ilogb.c
+++ b/sysdeps/ieee754/ldbl-opt/w_ilogb.c
@@ -1,5 +1,5 @@
 #include <math_ldbl_opt.h>
-#include <sysdeps/ieee754/dbl-64/s_ilogb.c>
+#include <math/w_ilogb.c>
 #if LONG_DOUBLE_COMPAT(libm, GLIBC_2_0)
 compat_symbol (libm, __ilogb, ilogbl, GLIBC_2_0);
 #endif
diff --git a/sysdeps/ieee754/ldbl-opt/w_ilogbl.c b/sysdeps/ieee754/ldbl-opt/w_ilogbl.c
new file mode 100644
index 0000000..36f83f6
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-opt/w_ilogbl.c
@@ -0,0 +1,5 @@
+#include <math_ldbl_opt.h>
+#undef weak_alias
+#define weak_alias(n,a)
+#include <math/w_ilogbl.c>
+long_double_symbol (libm, __ilogbl, ilogbl);
diff --git a/sysdeps/x86_64/fpu/s_ilogbl.S b/sysdeps/x86_64/fpu/e_ilogbl.S
index f59040c..44f9215 100644
--- a/sysdeps/x86_64/fpu/s_ilogbl.S
+++ b/sysdeps/x86_64/fpu/e_ilogbl.S
@@ -7,7 +7,7 @@
 
 #include <machine/asm.h>
 
-ENTRY(__ilogbl)
+ENTRY(__ieee754_ilogbl)
 	fldt	8(%rsp)
 /* I added the following ugly construct because ilogb(+-Inf) is
    required to return INT_MAX in ISO C99.
@@ -18,6 +18,8 @@ ENTRY(__ilogbl)
 	andb    %ah, %dh
 	cmpb    $0x05, %dh
 	je      1f		/* Is +-Inf, jump.  */
+	cmpb    $0x40, %dh
+	je      2f		/* Is +-Inf, jump.  */
 
 	fxtract
 	fstp	%st
@@ -31,5 +33,8 @@ ENTRY(__ilogbl)
 1:	fstp	%st
 	movl	$0x7fffffff, %eax
 	ret
-END (__ilogbl)
-weak_alias (__ilogbl, ilogbl)
+2:	fstp	%st
+	movl	$0x80000000, %eax	/* FP_ILOGB0  */
+	ret
+END (__ieee754_ilogbl)
+weak_alias (__ieee754_ilogbl, __ilogbl_finite)