Annotation of OpenXM_contrib/gmp/mpn/x86/pentium/copyi.asm, Revision 1.1
1.1 ! ohara 1: dnl Intel Pentium mpn_copyi -- copy limb vector, incrementing.
! 2:
! 3: dnl Copyright 1996, 2001, 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 P5: 1.25 cycles/limb
! 26:
! 27:
! 28: C void mpn_copyi (mp_ptr dst, mp_srcptr src, mp_size_t size);
! 29: C
! 30: C Destination prefetching is done to avoid repeated write-throughs on lines
! 31: C not already in L1.
! 32: C
! 33: C At least one of the src or dst pointer needs to be incremented rather than
! 34: C using indexing, so that there's somewhere to put the loop control without
! 35: C an AGI. Incrementing one and not two lets us keep loop overhead to 2
! 36: C cycles. Making it the src pointer incremented avoids an AGI on the %ecx
! 37: C subtracts in the finishup code.
! 38: C
! 39: C The block of finishup code is almost as big as the main loop itself, which
! 40: C is unfortunate, but it's faster that way than with say rep movsl, by about
! 41: C 10 cycles for instance on P55.
! 42: C
! 43: C There's nothing to be gained from MMX on P55, since it can do only one
! 44: C movq load (or store) per cycle, so the throughput would be the same as the
! 45: C code here (and even then only if src and dst have the same alignment mod
! 46: C 8).
! 47:
! 48: defframe(PARAM_SIZE,12)
! 49: defframe(PARAM_SRC, 8)
! 50: defframe(PARAM_DST, 4)
! 51:
! 52: PROLOGUE(mpn_copyi)
! 53: deflit(`FRAME',0)
! 54:
! 55: movl PARAM_SIZE, %ecx
! 56: movl PARAM_DST, %edx
! 57:
! 58: pushl %ebx FRAME_pushl()
! 59: pushl %esi FRAME_pushl()
! 60:
! 61: leal (%edx,%ecx,4), %edx C &dst[size-1]
! 62: xorl $-1, %ecx C -size-1
! 63:
! 64: movl PARAM_SRC, %esi
! 65: addl $8, %ecx C -size+7
! 66:
! 67: jns L(end)
! 68:
! 69: movl -28(%edx,%ecx,4), %eax C fetch destination cache line, dst[0]
! 70: nop
! 71:
! 72: L(top):
! 73: C eax scratch
! 74: C ebx scratch
! 75: C ecx counter, limbs, negative
! 76: C edx &dst[size-1]
! 77: C esi src, incrementing
! 78: C edi
! 79: C ebp
! 80:
! 81: movl (%edx,%ecx,4), %eax C fetch destination cache line
! 82: addl $8, %ecx
! 83:
! 84: movl (%esi), %eax C read words pairwise
! 85: movl 4(%esi), %ebx
! 86: movl %eax, -60(%edx,%ecx,4) C store words pairwise
! 87: movl %ebx, -56(%edx,%ecx,4)
! 88:
! 89: movl 8(%esi), %eax
! 90: movl 12(%esi), %ebx
! 91: movl %eax, -52(%edx,%ecx,4)
! 92: movl %ebx, -48(%edx,%ecx,4)
! 93:
! 94: movl 16(%esi), %eax
! 95: movl 20(%esi), %ebx
! 96: movl %eax, -44(%edx,%ecx,4)
! 97: movl %ebx, -40(%edx,%ecx,4)
! 98:
! 99: movl 24(%esi), %eax
! 100: movl 28(%esi), %ebx
! 101: movl %eax, -36(%edx,%ecx,4)
! 102: movl %ebx, -32(%edx,%ecx,4)
! 103:
! 104: leal 32(%esi), %esi
! 105: js L(top)
! 106:
! 107:
! 108: L(end):
! 109: C ecx 0 to 7, representing respectively 7 to 0 limbs remaining
! 110: C esi src end
! 111: C edx dst, next location to store
! 112:
! 113: subl $4, %ecx
! 114: jns L(no4)
! 115:
! 116: movl (%esi), %eax
! 117: movl 4(%esi), %ebx
! 118: movl %eax, -12(%edx,%ecx,4)
! 119: movl %ebx, -8(%edx,%ecx,4)
! 120:
! 121: movl 8(%esi), %eax
! 122: movl 12(%esi), %ebx
! 123: movl %eax, -4(%edx,%ecx,4)
! 124: movl %ebx, (%edx,%ecx,4)
! 125:
! 126: addl $16, %esi
! 127: addl $4, %ecx
! 128: L(no4):
! 129:
! 130: subl $2, %ecx
! 131: jns L(no2)
! 132:
! 133: movl (%esi), %eax
! 134: movl 4(%esi), %ebx
! 135: movl %eax, -4(%edx,%ecx,4)
! 136: movl %ebx, (%edx,%ecx,4)
! 137:
! 138: addl $8, %esi
! 139: addl $2, %ecx
! 140: L(no2):
! 141:
! 142: jnz L(done)
! 143:
! 144: movl (%esi), %eax
! 145: movl %eax, -4(%edx,%ecx,4) C risk of cache bank clash here
! 146:
! 147: L(done):
! 148: popl %esi
! 149: popl %ebx
! 150:
! 151: ret
! 152:
! 153: EPILOGUE()
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