+++ /dev/null
-dnl AMD K7 mpn_divexact_by3 -- mpn division by 3, expecting no remainder.
-dnl
-dnl K7: 8.0 cycles/limb
-
-
-dnl Copyright (C) 2000 Free Software 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_divexact_by3c (mp_ptr dst, mp_srcptr src, mp_size_t size,
-C mp_limb_t carry);
-
-defframe(PARAM_CARRY,16)
-defframe(PARAM_SIZE, 12)
-defframe(PARAM_SRC, 8)
-defframe(PARAM_DST, 4)
-
-dnl multiplicative inverse of 3, modulo 2^32
-deflit(INVERSE_3, 0xAAAAAAAB)
-
-dnl ceil(b/3) and floor(b*2/3) where b=2^32
-deflit(ONE_THIRD_CEIL, 0x55555556)
-deflit(TWO_THIRDS_FLOOR, 0xAAAAAAAA)
-
- .text
- ALIGN(32)
-
-PROLOGUE(mpn_divexact_by3c)
-deflit(`FRAME',0)
-
- movl PARAM_SRC, %ecx
- pushl %ebx defframe_pushl(SAVE_EBX)
-
- movl PARAM_CARRY, %ebx
- pushl %ebp defframe_pushl(SAVE_EBP)
-
- movl PARAM_SIZE, %ebp
- pushl %edi defframe_pushl(SAVE_EDI)
-
- movl (%ecx), %eax C src low limb
- pushl %esi defframe_pushl(SAVE_ESI)
-
- movl PARAM_DST, %edi
- movl $TWO_THIRDS_FLOOR, %esi
- leal -4(%ecx,%ebp,4), %ecx C &src[size-1]
-
- subl %ebx, %eax
-
- setc %bl
- decl %ebp
- jz L(last)
-
- leal (%edi,%ebp,4), %edi C &dst[size-1]
- negl %ebp
-
-
- ALIGN(16)
-L(top):
- C eax src limb, carry subtracted
- C ebx carry limb (0 or 1)
- C ecx &src[size-1]
- C edx scratch
- C esi TWO_THIRDS_FLOOR
- C edi &dst[size-1]
- C ebp counter, limbs, negative
-
- imull $INVERSE_3, %eax, %edx
-
- movl 4(%ecx,%ebp,4), %eax C next src limb
- cmpl $ONE_THIRD_CEIL, %edx
-
- sbbl $-1, %ebx C +1 if result>=ceil(b/3)
- cmpl %edx, %esi
-
- sbbl %ebx, %eax C and further 1 if result>=ceil(b*2/3)
- movl %edx, (%edi,%ebp,4)
- incl %ebp
-
- setc %bl C new carry
- jnz L(top)
-
-
-
-L(last):
- C eax src limb, carry subtracted
- C ebx carry limb (0 or 1)
- C ecx &src[size-1]
- C edx scratch
- C esi multiplier
- C edi &dst[size-1]
- C ebp
-
- imull $INVERSE_3, %eax
-
- cmpl $ONE_THIRD_CEIL, %eax
- movl %eax, (%edi)
- movl SAVE_EBP, %ebp
-
- sbbl $-1, %ebx C +1 if eax>=ceil(b/3)
- cmpl %eax, %esi
- movl $0, %eax
-
- adcl %ebx, %eax C further +1 if eax>=ceil(b*2/3)
- movl SAVE_EDI, %edi
- movl SAVE_ESI, %esi
-
- movl SAVE_EBX, %ebx
- addl $FRAME, %esp
-
- ret
-
-EPILOGUE()