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Diff for /OpenXM_contrib/gmp/mpn/alpha/Attic/cntlz.asm between version 1.1.1.1 and 1.1.1.2

-version 1.1.1.1, 2000/09/09 14:12:22
+version 1.1.1.2, 2003/08/25 16:06:18
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  dnl  Alpha auxiliary for longlong.h's count_leading_zeros
- dnl  Copyright (C) 1997, 2000 Free Software Foundation, Inc.
+ dnl  Copyright 1997, 2000, 2002 Free Software Foundation, Inc.
  dnl  This file is part of the GNU MP Library.
  dnl  The GNU MP Library is free software; you can redistribute it and/or modify
- dnl  it under the terms of the GNU Lesser General Public License as published by
+ dnl  it under the terms of the GNU Lesser General Public License as published
- dnl  the Free Software Foundation; either version 2.1 of the License, or (at your
+ dnl  by the Free Software Foundation; either version 2.1 of the License, or (at
- dnl  option) any later version.
+ dnl  your option) any later version.
  dnl  The GNU MP Library is distributed in the hope that it will be useful, but
  dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 Line 21  dnl  MA 02111-1307, USA.
 Line 21  dnl  MA 02111-1307, USA.
 Line 21  dnl  MA 02111-1307, USA.
  include(`../config.m4')
- dnl  DISCUSSION:
- dnl  Other methods have been tried, and using a 128-entry table actually trims
- dnl  about 10% of the execution time (on a 21164) when the table is in the L1
- dnl  cache.  But under non-benchmarking conditions, the table will hardly be in
- dnl  the L1 cache.  Tricky bit-fiddling methods with multiplies and magic tables
- dnl  are also possible, but they require many more instructions than the current
- dnl  code.  (But for count_trailing_zeros, such tricks are beneficial.)
- dnl  Finally, converting to floating-point and extracting the exponent is much
- dnl  slower.
  ASM_START()
- PROLOGUE(MPN(count_leading_zeros))
+ EXTERN(__clz_tab)
-         bis     r31,63,r0               C initialize partial result count
+ PROLOGUE(mpn_count_leading_zeros,gp)
+         cmpbge  r31,  r16, r1
-         srl     r16,32,r1               C shift down 32 steps -> r1
+         LEA(r3,__clz_tab)
-         cmovne  r1,r1,r16               C select r1 if non-zero
+         sra     r1,   1,   r1
-         cmovne  r1,31,r0                C if r1 is nonzero choose smaller count
+         xor     r1,   127, r1
+         srl     r16,  1,   r16
-         srl     r16,16,r1               C shift down 16 steps -> r1
+         addq    r1,   r3,  r1
-         subq    r0,16,r2                C generate new partial result count
+         ldq_u   r0,   0(r1)
-         cmovne  r1,r1,r16               C choose new r1 if non-zero
+         lda     r2,   64
-         cmovne  r1,r2,r0                C choose new count if r1 was non-zero
+         extbl   r0,   r1,   r0
+         s8subl  r0,   8,    r0
-         srl     r16,8,r1
+         srl     r16,  r0,   r16
-         subq    r0,8,r2
+         addq    r16,  r3,   r16
-         cmovne  r1,r1,r16
+         ldq_u   r1,   0(r16)
-         cmovne  r1,r2,r0
+         extbl   r1,   r16,  r1
+         subq    r2,   r1,   r2
-         srl     r16,4,r1
+         subq    r2,   r0,   r0
-         subq    r0,4,r2
+         ret     r31,  (r26),1
-         cmovne  r1,r1,r16
+ EPILOGUE(mpn_count_leading_zeros)
-         cmovne  r1,r2,r0
-         srl     r16,2,r1
-         subq    r0,2,r2
-         cmovne  r1,r1,r16
-         cmovne  r1,r2,r0
-         srl     r16,1,r1                C extract bit 1
-         subq    r0,r1,r0                C subtract it from partial result
-         ret     r31,(r26),1
- EPILOGUE(MPN(count_leading_zeros))
  ASM_END()

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