--- /dev/null
+dnl Intel Pentium mpn_lshift -- mpn left shift.
+dnl
+dnl cycles/limb
+dnl P5,P54: 6.0
+dnl P55: 5.375
+
+
+dnl Copyright (C) 1992, 1994, 1995, 1996, 1999, 2000 Free Software
+dnl Foundation, Inc.
+dnl
+dnl This file is part of the GNU MP Library.
+dnl
+dnl The GNU MP Library is free software; you can redistribute it and/or
+dnl modify it under the terms of the GNU Lesser General Public License as
+dnl published by the Free Software Foundation; either version 2.1 of the
+dnl License, or (at your option) any later version.
+dnl
+dnl The GNU MP Library is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+dnl Lesser General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU Lesser General Public
+dnl License along with the GNU MP Library; see the file COPYING.LIB. If
+dnl not, write to the Free Software Foundation, Inc., 59 Temple Place -
+dnl Suite 330, Boston, MA 02111-1307, USA.
+
+
+include(`../config.m4')
+
+
+C mp_limb_t mpn_lshift (mp_ptr dst, mp_srcptr src, mp_size_t size,
+C unsigned shift);
+C
+C The main shift-by-N loop should run at 5.375 c/l and that's what P55 does,
+C but P5 and P54 run only at 6.0 c/l, which is 4 cycles lost somewhere.
+
+defframe(PARAM_SHIFT,16)
+defframe(PARAM_SIZE, 12)
+defframe(PARAM_SRC, 8)
+defframe(PARAM_DST, 4)
+
+ .text
+ ALIGN(8)
+PROLOGUE(mpn_lshift)
+
+ pushl %edi
+ pushl %esi
+ pushl %ebx
+ pushl %ebp
+deflit(`FRAME',16)
+
+ movl PARAM_DST,%edi
+ movl PARAM_SRC,%esi
+ movl PARAM_SIZE,%ebp
+ movl PARAM_SHIFT,%ecx
+
+C We can use faster code for shift-by-1 under certain conditions.
+ cmp $1,%ecx
+ jne L(normal)
+ leal 4(%esi),%eax
+ cmpl %edi,%eax
+ jnc L(special) C jump if s_ptr + 1 >= res_ptr
+ leal (%esi,%ebp,4),%eax
+ cmpl %eax,%edi
+ jnc L(special) C jump if res_ptr >= s_ptr + size
+
+L(normal):
+ leal -4(%edi,%ebp,4),%edi
+ leal -4(%esi,%ebp,4),%esi
+
+ movl (%esi),%edx
+ subl $4,%esi
+ xorl %eax,%eax
+ shldl( %cl, %edx, %eax) C compute carry limb
+ pushl %eax C push carry limb onto stack
+
+ decl %ebp
+ pushl %ebp
+ shrl $3,%ebp
+ jz L(end)
+
+ movl (%edi),%eax C fetch destination cache line
+
+ ALIGN(4)
+L(oop): movl -28(%edi),%eax C fetch destination cache line
+ movl %edx,%ebx
+
+ movl (%esi),%eax
+ movl -4(%esi),%edx
+ shldl( %cl, %eax, %ebx)
+ shldl( %cl, %edx, %eax)
+ movl %ebx,(%edi)
+ movl %eax,-4(%edi)
+
+ movl -8(%esi),%ebx
+ movl -12(%esi),%eax
+ shldl( %cl, %ebx, %edx)
+ shldl( %cl, %eax, %ebx)
+ movl %edx,-8(%edi)
+ movl %ebx,-12(%edi)
+
+ movl -16(%esi),%edx
+ movl -20(%esi),%ebx
+ shldl( %cl, %edx, %eax)
+ shldl( %cl, %ebx, %edx)
+ movl %eax,-16(%edi)
+ movl %edx,-20(%edi)
+
+ movl -24(%esi),%eax
+ movl -28(%esi),%edx
+ shldl( %cl, %eax, %ebx)
+ shldl( %cl, %edx, %eax)
+ movl %ebx,-24(%edi)
+ movl %eax,-28(%edi)
+
+ subl $32,%esi
+ subl $32,%edi
+ decl %ebp
+ jnz L(oop)
+
+L(end): popl %ebp
+ andl $7,%ebp
+ jz L(end2)
+L(oop2):
+ movl (%esi),%eax
+ shldl( %cl,%eax,%edx)
+ movl %edx,(%edi)
+ movl %eax,%edx
+ subl $4,%esi
+ subl $4,%edi
+ decl %ebp
+ jnz L(oop2)
+
+L(end2):
+ shll %cl,%edx C compute least significant limb
+ movl %edx,(%edi) C store it
+
+ popl %eax C pop carry limb
+
+ popl %ebp
+ popl %ebx
+ popl %esi
+ popl %edi
+ ret
+
+
+C We loop from least significant end of the arrays, which is only
+C permissable if the source and destination don't overlap, since the
+C function is documented to work for overlapping source and destination.
+
+L(special):
+ movl (%esi),%edx
+ addl $4,%esi
+
+ decl %ebp
+ pushl %ebp
+ shrl $3,%ebp
+
+ addl %edx,%edx
+ incl %ebp
+ decl %ebp
+ jz L(Lend)
+
+ movl (%edi),%eax C fetch destination cache line
+
+ ALIGN(4)
+L(Loop):
+ movl 28(%edi),%eax C fetch destination cache line
+ movl %edx,%ebx
+
+ movl (%esi),%eax
+ movl 4(%esi),%edx
+ adcl %eax,%eax
+ movl %ebx,(%edi)
+ adcl %edx,%edx
+ movl %eax,4(%edi)
+
+ movl 8(%esi),%ebx
+ movl 12(%esi),%eax
+ adcl %ebx,%ebx
+ movl %edx,8(%edi)
+ adcl %eax,%eax
+ movl %ebx,12(%edi)
+
+ movl 16(%esi),%edx
+ movl 20(%esi),%ebx
+ adcl %edx,%edx
+ movl %eax,16(%edi)
+ adcl %ebx,%ebx
+ movl %edx,20(%edi)
+
+ movl 24(%esi),%eax
+ movl 28(%esi),%edx
+ adcl %eax,%eax
+ movl %ebx,24(%edi)
+ adcl %edx,%edx
+ movl %eax,28(%edi)
+
+ leal 32(%esi),%esi C use leal not to clobber carry
+ leal 32(%edi),%edi
+ decl %ebp
+ jnz L(Loop)
+
+L(Lend):
+ popl %ebp
+ sbbl %eax,%eax C save carry in %eax
+ andl $7,%ebp
+ jz L(Lend2)
+ addl %eax,%eax C restore carry from eax
+L(Loop2):
+ movl %edx,%ebx
+ movl (%esi),%edx
+ adcl %edx,%edx
+ movl %ebx,(%edi)
+
+ leal 4(%esi),%esi C use leal not to clobber carry
+ leal 4(%edi),%edi
+ decl %ebp
+ jnz L(Loop2)
+
+ jmp L(L1)
+L(Lend2):
+ addl %eax,%eax C restore carry from eax
+L(L1): movl %edx,(%edi) C store last limb
+
+ sbbl %eax,%eax
+ negl %eax
+
+ popl %ebp
+ popl %ebx
+ popl %esi
+ popl %edi
+ ret
+
+EPILOGUE()
projects / ghc-hetmet.git / blobdiff