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Annotation of OpenXM_contrib/gmp/mpn/x86/k7/mmx/com_n.asm, Revision 1.1.1.1

1.1       ohara       1: dnl  AMD Athlon mpn_com_n -- mpn bitwise one's complement.
                      2:
                      3: dnl  Copyright 2002 Free Software Foundation, Inc.
                      4: dnl
                      5: dnl  This file is part of the GNU MP Library.
                      6: dnl
                      7: dnl  The GNU MP Library is free software; you can redistribute it and/or
                      8: dnl  modify it under the terms of the GNU Lesser General Public License as
                      9: dnl  published by the Free Software Foundation; either version 2.1 of the
                     10: dnl  License, or (at your option) any later version.
                     11: dnl
                     12: dnl  The GNU MP Library is distributed in the hope that it will be useful,
                     13: dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
                     14: dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
                     15: dnl  Lesser General Public License for more details.
                     16: dnl
                     17: dnl  You should have received a copy of the GNU Lesser General Public
                     18: dnl  License along with the GNU MP Library; see the file COPYING.LIB.  If
                     19: dnl  not, write to the Free Software Foundation, Inc., 59 Temple Place -
                     20: dnl  Suite 330, Boston, MA 02111-1307, USA.
                     21:
                     22: include(`../config.m4')
                     23:
                     24:
                     25: C K7: 1.0 cycles/limb
                     26:
                     27:
                     28: C void mpn_com_n (mp_ptr dst, mp_srcptr src, mp_size_t size);
                     29: C
                     30: C The loop form below is necessary for the claimed speed.  It needs to be
                     31: C aligned to a 16 byte boundary and only 16 bytes long.  Maybe that's so it
                     32: C fits in a BTB entry.  The adjustments to %eax and %edx avoid offsets on
                     33: C the movq's and achieve the necessary size.
                     34: C
                     35: C If both src and dst are 4mod8, the loop runs at 1.5 c/l.  So long as one
                     36: C of the two is 0mod8, it runs at 1.0 c/l.  On that basis dst is checked
                     37: C (offset by the size, as per the loop addressing) and one high limb
                     38: C processed separately to get alignment.
                     39: C
                     40: C The padding for the nails case is unattractive, but shouldn't cost any
                     41: C cycles.  Explicit .byte's guarantee the desired instructions, at a point
                     42: C where we're probably stalled waiting for loads anyway.
                     43: C
                     44: C Enhancements:
                     45: C
                     46: C The combination load/pxor/store might be able to be unrolled to approach
                     47: C 0.5 c/l if desired.
                     48:
                     49: defframe(PARAM_SIZE,12)
                     50: defframe(PARAM_SRC, 8)
                     51: defframe(PARAM_DST, 4)
                     52:
                     53:        TEXT
                     54:        ALIGN(16)
                     55:
                     56: PROLOGUE(mpn_com_n)
                     57: deflit(`FRAME',0)
                     58:
                     59:        movl    PARAM_DST, %edx
                     60:        movl    PARAM_SIZE, %ecx
                     61:        pcmpeqd %mm7, %mm7
                     62:
                     63:        leal    (%edx,%ecx,4), %eax
                     64:        andl    $4, %eax
                     65: ifelse(GMP_NAIL_BITS,0,,
                     66: `      psrld   $GMP_NAIL_BITS, %mm7')          C GMP_NUMB_MASK
                     67:
                     68:        movl    PARAM_SRC, %eax
                     69:        movd    -4(%eax,%ecx,4), %mm0           C src high limb
                     70:
                     71: ifelse(GMP_NAIL_BITS,0,,
                     72: `      C padding for alignment below
                     73:        .byte   0x8d, 0xb6, 0x00, 0x00, 0x00, 0x00      C lea 0(%esi),%esi
                     74:        .byte   0x8d, 0xbf, 0x00, 0x00, 0x00, 0x00      C lea 0(%edi),%edi
                     75: ')
                     76:
                     77:        jz      L(aligned)
                     78:
                     79:        pxor    %mm7, %mm0
                     80:        movd    %mm0, -4(%edx,%ecx,4)           C dst high limb
                     81:        decl    %ecx
                     82:        jz      L(done)
                     83: L(aligned):
                     84:
                     85:        addl    $4, %eax
                     86:        addl    $4, %edx
                     87:        decl    %ecx
                     88:        jz      L(one)
                     89:
                     90:        C offset 0x30 for no nails, or 0x40 for nails
                     91:        ALIGN(16)
                     92: L(top):
                     93:        C eax   src
                     94:        C ebx
                     95:        C ecx   counter
                     96:        C edx   dst
                     97:
                     98:        subl    $2, %ecx
                     99:        movq    (%eax,%ecx,4), %mm0
                    100:        pxor    %mm7, %mm0
                    101:        movq    %mm0, (%edx,%ecx,4)
                    102:        jg      L(top)
                    103:
                    104:        jnz     L(done)                         C if size even
                    105:
                    106: L(one):
                    107:        movd    -4(%eax), %mm0                  C src low limb
                    108:        pxor    %mm7, %mm0
                    109:        movd    %mm0, -4(%edx)                  C dst low limb
                    110:
                    111: L(done):
                    112:        emms
                    113:
                    114:        ret
                    115:
                    116: EPILOGUE()