Revise WFE detection

Detail:
  s/CPUFeatures - Take account of the fact that single-core ARMv7+ chips implement MPIDR but aren't guaranteed to implement a useful WFE. So for ARMv7+, only report WFE as being available/useful if MPIDR indicates that virtualisation extensions are supported.
Admin:
  Tested on Raspberry Pi 1 & 3, BB-xM


Version 5.35, 4.79.2.322. Tagged as 'Kernel-5_35-4_79_2_322'

VersionASM

@@ -13,11 +13,11 @@
                         GBLS    Module_ComponentPath
 Module_MajorVersion     SETS    "5.35"
 Module_Version          SETA    535
-Module_MinorVersion     SETS    "4.79.2.321"
+Module_MinorVersion     SETS    "4.79.2.322"
 Module_Date             SETS    "22 May 2016"
 Module_ApplicationDate  SETS    "22-May-16"
 Module_ComponentName    SETS    "Kernel"
 Module_ComponentPath    SETS    "castle/RiscOS/Sources/Kernel"
-Module_FullVersion      SETS    "5.35 (4.79.2.321)"
-Module_HelpVersion      SETS    "5.35 (22 May 2016) 4.79.2.321"
+Module_FullVersion      SETS    "5.35 (4.79.2.322)"
+Module_HelpVersion      SETS    "5.35 (22 May 2016) 4.79.2.322"
                         END

VersionNum

@@ -5,12 +5,12 @@
  *
  */
 #define Module_MajorVersion_CMHG        5.35
-#define Module_MinorVersion_CMHG        4.79.2.321
+#define Module_MinorVersion_CMHG        4.79.2.322
 #define Module_Date_CMHG                22 May 2016
 
 #define Module_MajorVersion             "5.35"
 #define Module_Version                  535
-#define Module_MinorVersion             "4.79.2.321"
+#define Module_MinorVersion             "4.79.2.322"
 #define Module_Date                     "22 May 2016"
 
 #define Module_ApplicationDate          "22-May-16"
@@ -18,6 +18,6 @@
 #define Module_ComponentName            "Kernel"
 #define Module_ComponentPath            "castle/RiscOS/Sources/Kernel"
 
-#define Module_FullVersion              "5.35 (4.79.2.321)"
-#define Module_HelpVersion              "5.35 (22 May 2016) 4.79.2.321"
+#define Module_FullVersion              "5.35 (4.79.2.322)"
+#define Module_HelpVersion              "5.35 (22 May 2016) 4.79.2.322"
 #define Module_LibraryVersionInfo       "5:35"

s/CPUFeatures

@@ -250,9 +250,10 @@ CalcCPUFeatures ROUT
         MRC     p15, 0, r5, c0, c0, 1   ; Cache type register
         TST     r5, #1<<31              ; EQ = ARMv6, NE = ARMv7+
         SetFeatureEQ Rotated_loads
-        ; Guess whether WFE does something useful by whether we're a multicore chip (i.e. MPIDR is implemented)
+        ; Guess whether WFE does something useful by whether we're a multicore chip
         MRC     p15, 0, r5, c0, c0, 5   ; MPIDR
-        MRC     p15, 0, r6, c0, c0, 0   ; MIDR
+        MRCEQ   p15, 0, r6, c0, c0, 0   ; ARMv6: Register is optional, so compare value against MIDR to see if it's implemented. There's no virtualisation extensions flag so assume the check against MIDR will be good enough.
+        BICNE   r6, r5, #1<<31          ; ARMv7+: Register is mandatory, but useful WFE still not guaranteed. So check if virtualisation extensions implemented (bit 31 set).
         TEQ     r5, r6
         SetFeatureNE WFE
         ; Detect instructions introduced by virtualisation extensions