dnl x86 mpn_bdiv_q_1 -- mpn by limb exact division.
dnl Rearranged from mpn/x86/dive_1.asm by Marco Bodrato.
dnl Copyright 2001, 2002, 2007, 2011 Free Software Foundation, Inc.
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 modify
dnl it under the terms of either:
dnl
dnl * the GNU Lesser General Public License as published by the Free
dnl Software Foundation; either version 3 of the License, or (at your
dnl option) any later version.
dnl
dnl or
dnl
dnl * the GNU General Public License as published by the Free Software
dnl Foundation; either version 2 of the License, or (at your option) any
dnl later version.
dnl
dnl or both in parallel, as here.
dnl
dnl The GNU MP Library is distributed in the hope that it will be useful, but
dnl WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
dnl for more details.
dnl
dnl You should have received copies of the GNU General Public License and the
dnl GNU Lesser General Public License along with the GNU MP Library. If not,
dnl see https://www.gnu.org/licenses/.
include(`../config.m4')
C cycles/limb
C P54 30.0
C P55 29.0
C P6 13.0 odd divisor, 12.0 even (strangely)
C K6 14.0
C K7 12.0
C P4 42.0
MULFUNC_PROLOGUE(mpn_bdiv_q_1 mpn_pi1_bdiv_q_1)
defframe(PARAM_SHIFT, 24)
defframe(PARAM_INVERSE,20)
defframe(PARAM_DIVISOR,16)
defframe(PARAM_SIZE, 12)
defframe(PARAM_SRC, 8)
defframe(PARAM_DST, 4)
dnl re-use parameter space
define(VAR_INVERSE,`PARAM_SRC')
TEXT
C mp_limb_t
C mpn_pi1_bdiv_q_1 (mp_ptr dst, mp_srcptr src, mp_size_t size, mp_limb_t divisor,
C mp_limb_t inverse, int shift)
ALIGN(16)
PROLOGUE(mpn_pi1_bdiv_q_1)
deflit(`FRAME',0)
movl PARAM_SHIFT, %ecx
pushl %ebp FRAME_pushl()
movl PARAM_INVERSE, %eax
movl PARAM_SIZE, %ebp
pushl %ebx FRAME_pushl()
L(common):
pushl %edi FRAME_pushl()
pushl %esi FRAME_pushl()
movl PARAM_SRC, %esi
movl PARAM_DST, %edi
leal (%esi,%ebp,4), %esi C src end
leal (%edi,%ebp,4), %edi C dst end
negl %ebp C -size
movl %eax, VAR_INVERSE
movl (%esi,%ebp,4), %eax C src[0]
xorl %ebx, %ebx
xorl %edx, %edx
incl %ebp
jz L(one)
movl (%esi,%ebp,4), %edx C src[1]
shrdl( %cl, %edx, %eax)
movl VAR_INVERSE, %edx
jmp L(entry)
ALIGN(8)
nop C k6 code alignment
nop
L(top):
C eax q
C ebx carry bit, 0 or -1
C ecx shift
C edx carry limb
C esi src end
C edi dst end
C ebp counter, limbs, negative
movl -4(%esi,%ebp,4), %eax
subl %ebx, %edx C accumulate carry bit
movl (%esi,%ebp,4), %ebx
shrdl( %cl, %ebx, %eax)
subl %edx, %eax C apply carry limb
movl VAR_INVERSE, %edx
sbbl %ebx, %ebx
L(entry):
imull %edx, %eax
movl %eax, -4(%edi,%ebp,4)
movl PARAM_DIVISOR, %edx
mull %edx
incl %ebp
jnz L(top)
movl -4(%esi), %eax C src high limb
L(one):
shrl %cl, %eax
popl %esi FRAME_popl()
addl %ebx, %eax C apply carry bit
subl %edx, %eax C apply carry limb
imull VAR_INVERSE, %eax
movl %eax, -4(%edi)
popl %edi
popl %ebx
popl %ebp
ret
EPILOGUE()
C mp_limb_t mpn_bdiv_q_1 (mp_ptr dst, mp_srcptr src, mp_size_t size,
C mp_limb_t divisor);
C
ALIGN(16)
PROLOGUE(mpn_bdiv_q_1)
deflit(`FRAME',0)
movl PARAM_DIVISOR, %eax
pushl %ebp FRAME_pushl()
movl $-1, %ecx C shift count
movl PARAM_SIZE, %ebp
pushl %ebx FRAME_pushl()
L(strip_twos):
incl %ecx
shrl %eax
jnc L(strip_twos)
leal 1(%eax,%eax), %ebx C d without twos
andl $127, %eax C d/2, 7 bits
ifdef(`PIC',`
LEA( binvert_limb_table, %edx)
movzbl (%eax,%edx), %eax C inv 8 bits
',`
movzbl binvert_limb_table(%eax), %eax C inv 8 bits
')
leal (%eax,%eax), %edx C 2*inv
movl %ebx, PARAM_DIVISOR C d without twos
imull %eax, %eax C inv*inv
imull %ebx, %eax C inv*inv*d
subl %eax, %edx C inv = 2*inv - inv*inv*d
leal (%edx,%edx), %eax C 2*inv
imull %edx, %edx C inv*inv
imull %ebx, %edx C inv*inv*d
subl %edx, %eax C inv = 2*inv - inv*inv*d
ASSERT(e,` C expect d*inv == 1 mod 2^GMP_LIMB_BITS
pushl %eax FRAME_pushl()
imull PARAM_DIVISOR, %eax
cmpl $1, %eax
popl %eax FRAME_popl()')
jmp L(common)
EPILOGUE()
ASM_END()