[RFA] Change AUXV bit checked to decide the size of the FPSCR

[Thiago Jung Bauermann <bauerman@br.ibm.com>]

Hi,

I recently found out that even though Power7 will support ISA 2.05, it
will have the PPC_FEATURE_ARCH_2_06 bit set, but not the
PPC_FEATURE_ARCH_2_05 bit (even though it will also support ISA 2.05). 

For this reason, I'm changing GDB to check for DFP to decide what is the
size of the FPSCR (it changed from 32 bits to 64 bits with ISA 2.05 and
newer). Since for now the only higher bits used are for Decimal Floating
Point, I am changing the code to check the DFP bit in AUXV.

Regression-tested in Linux on a Power6 machine, running the testsuite in
both native and gdbserver configurations.

Ok?
-- 
[]'s
Thiago Jung Bauermann
IBM Linux Technology Center


2009-03-23  Thiago Jung Bauermann  <bauerman@br.ibm.com>

gdb/
	* ppc-linux-nat.c (PPC_FEATURE_ARCH_2_05): Remove #define.
	(PPC_FEATURE_HAS_DFP): New #define.
	(ppc_linux_read_description): Check for DFP feature instead of
	ISA 2.05 to decide on size of the FPSCR.

gdbserver/
	* linux-ppc-low.c (PPC_FEATURE_ARCH_2_05): Remove #define.
	(PPC_FEATURE_HAS_DFP): New #define.
	(ppc_arch_setup): Check for DFP feature instead of ISA 2.05 to decide on
	size of the FPSCR.

diff --git a/gdb/gdbserver/linux-ppc-low.c b/gdb/gdbserver/linux-ppc-low.c
index b184d5c..29ae832 100644
--- a/gdb/gdbserver/linux-ppc-low.c
+++ b/gdb/gdbserver/linux-ppc-low.c
@@ -28,7 +28,7 @@
 #define PPC_FEATURE_HAS_VSX		0x00000080
 #define PPC_FEATURE_HAS_ALTIVEC         0x10000000
 #define PPC_FEATURE_HAS_SPE             0x00800000
-#define PPC_FEATURE_ARCH_2_05           0x00001000
+#define PPC_FEATURE_HAS_DFP             0x00000400
 
 static unsigned long ppc_hwcap;
 
@@ -274,14 +274,14 @@ ppc_arch_setup (void)
       ppc_get_hwcap (&ppc_hwcap);
       if (ppc_hwcap & PPC_FEATURE_HAS_VSX)
 	{
-	  if (ppc_hwcap & PPC_FEATURE_ARCH_2_05)
+	  if (ppc_hwcap & PPC_FEATURE_HAS_DFP)
 	    init_registers_powerpc_isa205_vsx64l ();
 	  else
 	    init_registers_powerpc_vsx64l ();
 	}
       else if (ppc_hwcap & PPC_FEATURE_HAS_ALTIVEC)
 	{
-	  if (ppc_hwcap & PPC_FEATURE_ARCH_2_05)
+	  if (ppc_hwcap & PPC_FEATURE_HAS_DFP)
 	    init_registers_powerpc_isa205_altivec64l ();
 	  else
 	    init_registers_powerpc_altivec64l ();
@@ -297,14 +297,14 @@ ppc_arch_setup (void)
   ppc_get_hwcap (&ppc_hwcap);
   if (ppc_hwcap & PPC_FEATURE_HAS_VSX)
     {
-      if (ppc_hwcap & PPC_FEATURE_ARCH_2_05)
+      if (ppc_hwcap & PPC_FEATURE_HAS_DFP)
 	init_registers_powerpc_isa205_vsx32l ();
       else
 	init_registers_powerpc_vsx32l ();
     }
   else if (ppc_hwcap & PPC_FEATURE_HAS_ALTIVEC)
     {
-      if (ppc_hwcap & PPC_FEATURE_ARCH_2_05)
+      if (ppc_hwcap & PPC_FEATURE_HAS_DFP)
 	init_registers_powerpc_isa205_altivec32l ();
       else
 	init_registers_powerpc_altivec32l ();
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 034201b..0c0f04c 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -63,8 +63,8 @@
 #ifndef PPC_FEATURE_BOOKE
 #define PPC_FEATURE_BOOKE 0x00008000
 #endif
-#ifndef PPC_FEATURE_ARCH_2_05
-#define PPC_FEATURE_ARCH_2_05	0x00001000 /* ISA 2.05 */
+#ifndef PPC_FEATURE_HAS_DFP
+#define PPC_FEATURE_HAS_DFP	0x00000400  /* Decimal Floating Point.  */
 #endif
 
 /* Glibc's headers don't define PTRACE_GETVRREGS so we cannot use a
@@ -1290,7 +1290,7 @@ ppc_linux_read_description (struct target_ops *ops)
 	perror_with_name (_("Unable to fetch AltiVec registers"));
     }
 
-  if (ppc_linux_get_hwcap () & PPC_FEATURE_ARCH_2_05)
+  if (ppc_linux_get_hwcap () & PPC_FEATURE_HAS_DFP)
     isa205 = 1;
 
   /* Check for 64-bit inferior process.  This is the case when the host is