2005-09-15 Jay Monkman

	PR 365/rtems
	* rtems/score/arm.h, rtems/score/cpu.h: Removed unused ARM_HAS_CLZ
	macro

3 files changed, 14 insertions, 99 deletions

diff --git a/cpukit/score/cpu/arm/ChangeLog b/cpukit/score/cpu/arm/ChangeLog
index 3dd5c678bd..3c21c3d4b2 100644
--- a/cpukit/score/cpu/arm/ChangeLog
+++ b/cpukit/score/cpu/arm/ChangeLog
@@ -1,3 +1,9 @@
+2005-09-15	Jay Monkman <jtm@lopingdog.com>
+
+	PR 365/rtems
+	* rtems/score/arm.h, rtems/score/cpu.h: Removed unused ARM_HAS_CLZ
+	macro.
+
 2005-02-08	Ralf Corsepius <ralf.corsepius@rtems.org>
 
 	* Makefile.am: Split out preinstallation rules.
diff --git a/cpukit/score/cpu/arm/rtems/score/arm.h b/cpukit/score/cpu/arm/rtems/score/arm.h
index ce2e9dfb51..e9a21baf7c 100644
--- a/cpukit/score/cpu/arm/rtems/score/arm.h
+++ b/cpukit/score/cpu/arm/rtems/score/arm.h
@@ -34,27 +34,21 @@ extern "C" {
  */
 #if defined(__ARM_ARCH_4__)
 #  define CPU_MODEL_NAME  "ARMv4"
-#  define ARM_HAS_CLZ     0
 
 #elif defined(__ARM_ARCH_4T__)
 #  define CPU_MODEL_NAME  "ARMv4T"
-#  define ARM_HAS_CLZ     0
 
 #elif defined(__ARM_ARCH_5__)
 #  define CPU_MODEL_NAME  "ARMv5"
-#  define ARM_HAS_CLZ     1
 
 #elif defined(__ARM_ARCH_5T__)
 #  define CPU_MODEL_NAME  "ARMv5T"
-#  define ARM_HAS_CLZ     1
 
 #elif defined(__ARM_ARCH_5E__)
 #  define CPU_MODEL_NAME  "ARMv5E"
-#  define ARM_HAS_CLZ     1
 
 #elif defined(__ARM_ARCH_5TE__)
 #  define CPU_MODEL_NAME  "ARMv5TE"
-#  define ARM_HAS_CLZ     1
 
 #else
 #  error "Unsupported CPU Model"
diff --git a/cpukit/score/cpu/arm/rtems/score/cpu.h b/cpukit/score/cpu/arm/rtems/score/cpu.h
index 5ccc1d77da..68c6b291f5 100644
--- a/cpukit/score/cpu/arm/rtems/score/cpu.h
+++ b/cpukit/score/cpu/arm/rtems/score/cpu.h
@@ -685,101 +685,16 @@ void _CPU_Context_Initialize(
 /* end of Fatal Error manager macros */
 
 /* Bitfield handler macros */
-
-/*
- *  This routine sets _output to the bit number of the first bit
- *  set in _value.  _value is of CPU dependent type Priority_Bit_map_control.
- *  This type may be either 16 or 32 bits wide although only the 16
- *  least significant bits will be used.
- *
- *  There are a number of variables in using a "find first bit" type
- *  instruction.
- *
- *    (1) What happens when run on a value of zero?
- *    (2) Bits may be numbered from MSB to LSB or vice-versa.
- *    (3) The numbering may be zero or one based.
- *    (4) The "find first bit" instruction may search from MSB or LSB.
- *
- *  RTEMS guarantees that (1) will never happen so it is not a concern.
- *  (2),(3), (4) are handled by the macros _CPU_Priority_mask() and
- *  _CPU_Priority_bits_index().  These three form a set of routines
- *  which must logically operate together.  Bits in the _value are
- *  set and cleared based on masks built by _CPU_Priority_mask().
- *  The basic major and minor values calculated by _Priority_Major()
- *  and _Priority_Minor() are "massaged" by _CPU_Priority_bits_index()
- *  to properly range between the values returned by the "find first bit"
- *  instruction.  This makes it possible for _Priority_Get_highest() to
- *  calculate the major and directly index into the minor table.
- *  This mapping is necessary to ensure that 0 (a high priority major/minor)
- *  is the first bit found.
- *
- *  This entire "find first bit" and mapping process depends heavily
- *  on the manner in which a priority is broken into a major and minor
- *  components with the major being the 4 MSB of a priority and minor
- *  the 4 LSB.  Thus (0 << 4) + 0 corresponds to priority 0 -- the highest
- *  priority.  And (15 << 4) + 14 corresponds to priority 254 -- the next
- *  to the lowest priority.
- *
- *  If your CPU does not have a "find first bit" instruction, then
- *  there are ways to make do without it.  Here are a handful of ways
- *  to implement this in software:
+/* 
+ * If we had a particularly fast function for finding the first
+ * bit set in a word, it would go here. Since we don't (*), we'll
+ * just use the universal macros.
  *
- *    - a series of 16 bit test instructions
- *    - a "binary search using if's"
- *    - _number = 0
- *      if _value > 0x00ff
- *        _value >>=8
- *        _number = 8;
- *
- *      if _value > 0x0000f
- *        _value >=8
- *        _number += 4
- *
- *      _number += bit_set_table[ _value ]
- *
- *    where bit_set_table[ 16 ] has values which indicate the first
- *      bit set
- */
-#if (ARM_HAS_CLZ == 0)
-#  define CPU_USE_GENERIC_BITFIELD_CODE TRUE
-#  define CPU_USE_GENERIC_BITFIELD_DATA TRUE
-#else 
-#  define CPU_USE_GENERIC_BITFIELD_CODE FALSE
-#  define CPU_USE_GENERIC_BITFIELD_DATA FALSE
-
-#  define _CPU_Bitfield_Find_first_bit( _value, _output ) \
-   { \
-     (_output) = 0;   /* do something to prevent warnings */ \
-   }
-
-/* end of Bitfield handler macros */
-
-/*
- *  This routine builds the mask which corresponds to the bit fields
- *  as searched by _CPU_Bitfield_Find_first_bit().  See the discussion
- *  for that routine.
+ * (*) On ARM V5 and later, there's a CLZ function which could be
+ *     used to implement much quicker than the default macro.
  */
-
-
-#  define _CPU_Priority_Mask( _bit_number ) \
-   ( 1 << (_bit_number) )
-
-
-/*
- *  This routine translates the bit numbers returned by
- *  _CPU_Bitfield_Find_first_bit() into something suitable for use as
- *  a major or minor component of a priority.  See the discussion
- *  for that routine.
- */
-
-
-#  define _CPU_Priority_bits_index( _priority ) \
-   (_priority)
-
-#  error "Implement CLZ version of priority bit functions for ARMv5"
-#endif
-
-/* end of Priority handler macros */
+#define CPU_USE_GENERIC_BITFIELD_CODE TRUE
+#define CPU_USE_GENERIC_BITFIELD_DATA TRUE
 
 /* functions */