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dnl AMD64 mpn_divexact_1 -- mpn by limb exact division.
dnl Copyright 2001, 2002, 2004-2006, 2010-2012 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 norm unorm
C AMD K8,K9 11 11
C AMD K10 11 11
C Intel P4 ?
C Intel core2 13.5 13.25
C Intel corei 14.25
C Intel atom 34 36
C VIA nano 19.25 19.25
C INPUT PARAMETERS
C rp rdi
C up rsi
C n rdx
C divisor rcx
ABI_SUPPORT(DOS64)
ABI_SUPPORT(STD64)
ASM_START()
TEXT
ALIGN(16)
PROLOGUE(mpn_divexact_1)
FUNC_ENTRY(4)
push %rbx
mov %rcx, %rax
xor R32(%rcx), R32(%rcx) C shift count
mov %rdx, %r8
bt $0, R32(%rax)
jc L(odd) C skip bsfq unless divisor is even
bsf %rax, %rcx
shr R8(%rcx), %rax
L(odd): mov %rax, %rbx
shr R32(%rax)
and $127, R32(%rax) C d/2, 7 bits
LEA( binvert_limb_table, %rdx)
movzbl (%rdx,%rax), R32(%rax) C inv 8 bits
mov %rbx, %r11 C d without twos
lea (%rax,%rax), R32(%rdx) C 2*inv
imul R32(%rax), R32(%rax) C inv*inv
imul R32(%rbx), R32(%rax) C inv*inv*d
sub R32(%rax), R32(%rdx) C inv = 2*inv - inv*inv*d, 16 bits
lea (%rdx,%rdx), R32(%rax) C 2*inv
imul R32(%rdx), R32(%rdx) C inv*inv
imul R32(%rbx), R32(%rdx) C inv*inv*d
sub R32(%rdx), R32(%rax) C inv = 2*inv - inv*inv*d, 32 bits
lea (%rax,%rax), %r10 C 2*inv
imul %rax, %rax C inv*inv
imul %rbx, %rax C inv*inv*d
sub %rax, %r10 C inv = 2*inv - inv*inv*d, 64 bits
lea (%rsi,%r8,8), %rsi C up end
lea -8(%rdi,%r8,8), %rdi C rp end
neg %r8 C -n
mov (%rsi,%r8,8), %rax C up[0]
inc %r8
jz L(one)
test R32(%rcx), R32(%rcx)
jnz L(unorm) C branch if count != 0
xor R32(%rbx), R32(%rbx)
jmp L(nent)
ALIGN(8)
L(ntop):mul %r11 C carry limb in rdx 0 10
mov -8(%rsi,%r8,8), %rax C
sub %rbx, %rax C apply carry bit
setc %bl C
sub %rdx, %rax C apply carry limb 5
adc $0, %rbx C 6
L(nent):imul %r10, %rax C 6
mov %rax, (%rdi,%r8,8) C
inc %r8 C
jnz L(ntop)
mov -8(%rsi), %r9 C up high limb
jmp L(com)
L(unorm):
mov (%rsi,%r8,8), %r9 C up[1]
shr R8(%rcx), %rax C
neg R32(%rcx)
shl R8(%rcx), %r9 C
neg R32(%rcx)
or %r9, %rax
xor R32(%rbx), R32(%rbx)
jmp L(uent)
ALIGN(8)
L(utop):mul %r11 C carry limb in rdx 0 10
mov (%rsi,%r8,8), %rax C
shl R8(%rcx), %rax C
neg R32(%rcx)
or %r9, %rax
sub %rbx, %rax C apply carry bit
setc %bl C
sub %rdx, %rax C apply carry limb 5
adc $0, %rbx C 6
L(uent):imul %r10, %rax C 6
mov (%rsi,%r8,8), %r9 C
shr R8(%rcx), %r9 C
neg R32(%rcx)
mov %rax, (%rdi,%r8,8) C
inc %r8 C
jnz L(utop)
L(com): mul %r11 C carry limb in rdx
sub %rbx, %r9 C apply carry bit
sub %rdx, %r9 C apply carry limb
imul %r10, %r9
mov %r9, (%rdi)
pop %rbx
FUNC_EXIT()
ret
L(one): shr R8(%rcx), %rax
imul %r10, %rax
mov %rax, (%rdi)
pop %rbx
FUNC_EXIT()
ret
EPILOGUE()
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