mode1o.asm
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上传日期:2022-08-06
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- dnl Intel P6 mpn_modexact_1_odd -- exact division style remainder.
- dnl Copyright 2000, 2001, 2002, 2007 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 3 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 License
- dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/.
- include(`../config.m4')
- C P6: 10.0 cycles/limb
- C mp_limb_t mpn_modexact_1_odd (mp_srcptr src, mp_size_t size,
- C mp_limb_t divisor);
- C mp_limb_t mpn_modexact_1c_odd (mp_srcptr src, mp_size_t size,
- C mp_limb_t divisor, mp_limb_t carry);
- C
- C It's not worth skipping a step at the end when high<divisor since the main
- C loop is only 10 cycles.
- defframe(PARAM_CARRY, 16)
- defframe(PARAM_DIVISOR,12)
- defframe(PARAM_SIZE, 8)
- defframe(PARAM_SRC, 4)
- dnl Not enough room under modexact_1 to make these re-use the parameter
- dnl space, unfortunately.
- defframe(SAVE_EBX, -4)
- defframe(SAVE_ESI, -8)
- defframe(SAVE_EDI, -12)
- deflit(STACK_SPACE, 12)
- TEXT
- ALIGN(16)
- PROLOGUE(mpn_modexact_1c_odd)
- deflit(`FRAME',0)
- movl PARAM_CARRY, %ecx
- jmp L(start_1c)
- EPILOGUE()
- ALIGN(16)
- PROLOGUE(mpn_modexact_1_odd)
- deflit(`FRAME',0)
- xorl %ecx, %ecx
- L(start_1c):
- movl PARAM_DIVISOR, %eax
- subl $STACK_SPACE, %esp FRAME_subl_esp(STACK_SPACE)
- movl %esi, SAVE_ESI
- movl PARAM_SRC, %esi
- shrl %eax C d/2
- movl %edi, SAVE_EDI
- andl $127, %eax
- ifdef(`PIC',`
- LEA( binvert_limb_table, %edi)
- movzbl (%eax,%edi), %edi C inv 8 bits
- ',`
- movzbl binvert_limb_table(%eax), %edi C inv 8 bits
- ')
- xorl %edx, %edx C initial extra carry
- leal (%edi,%edi), %eax C 2*inv
- imull %edi, %edi C inv*inv
- movl %ebx, SAVE_EBX
- movl PARAM_SIZE, %ebx
- imull PARAM_DIVISOR, %edi C inv*inv*d
- subl %edi, %eax C inv = 2*inv - inv*inv*d
- leal (%eax,%eax), %edi C 2*inv
- imull %eax, %eax C inv*inv
- imull PARAM_DIVISOR, %eax C inv*inv*d
- leal (%esi,%ebx,4), %esi C src end
- negl %ebx C -size
- subl %eax, %edi C inv = 2*inv - inv*inv*d
- ASSERT(e,` C d*inv == 1 mod 2^GMP_LIMB_BITS
- movl PARAM_DIVISOR, %eax
- imull %edi, %eax
- cmpl $1, %eax')
- C The dependent chain here is
- C
- C subl %edx, %eax 1
- C imull %edi, %eax 4
- C mull PARAM_DIVISOR 5
- C ----
- C total 10
- C
- C and this is the measured speed. No special scheduling is necessary, out
- C of order execution hides the load latency.
- L(top):
- C eax scratch (src limb)
- C ebx counter, limbs, negative
- C ecx carry bit, 0 or 1
- C edx carry limb, high of last product
- C esi &src[size]
- C edi inverse
- C ebp
- movl (%esi,%ebx,4), %eax
- subl %ecx, %eax
- sbbl %ecx, %ecx
- subl %edx, %eax
- sbbl $0, %ecx
- imull %edi, %eax
- negl %ecx
- mull PARAM_DIVISOR
- incl %ebx
- jnz L(top)
- movl SAVE_ESI, %esi
- leal (%ecx,%edx), %eax
- movl SAVE_EDI, %edi
- movl SAVE_EBX, %ebx
- addl $STACK_SPACE, %esp
- ret
- EPILOGUE()