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dnl AMD64 mpn_gcd_11 -- 1 x 1 gcd.
dnl Based on the K7 gcd_1.asm, by Kevin Ryde. Rehacked for AMD64 by Torbjorn
dnl Granlund.
dnl Copyright 2000-2002, 2005, 2009, 2011, 2012, 2017 Free Software
dnl 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/bit (approx)
C AMD K8,K9 5.21 (4.95)
C AMD K10 5.15 (5.00)
C AMD bd1 5.42 (5.14)
C AMD bobcat 6.71 (6.56)
C Intel P4 13.5 (12.75)
C Intel core2 6.20 (6.16)
C Intel NHM 6.49 (6.25)
C Intel SBR 7.75 (7.57)
C Intel atom 8.77 (8.54)
C VIA nano 6.60 (6.20)
C Numbers measured with: speed -CD -s16-64 -t48 mpn_gcd_1
C ctz_table[n] is the number of trailing zeros on n, or MAXSHIFT if n==0.
deflit(MAXSHIFT, 7)
deflit(MASK, eval((m4_lshift(1,MAXSHIFT))-1))
PROTECT(`ctz_table')
DEF_OBJECT(ctz_table,64)
.byte MAXSHIFT
forloop(i,1,MASK,
` .byte m4_count_trailing_zeros(i)
')
END_OBJECT(ctz_table)
define(`u0', `%rdi')
define(`v0', `%rsi')
ABI_SUPPORT(DOS64)
ABI_SUPPORT(STD64)
ASM_START()
TEXT
ALIGN(16)
PROLOGUE(mpn_gcd_11)
FUNC_ENTRY(2)
LEA( ctz_table, %r8)
jmp L(ent)
ALIGN(16)
L(top): cmovc %rdx, u0 C u = |u - v|
cmovc %rax, v0 C v = min(u,v)
L(mid): and $MASK, R32(%rdx)
movzbl (%r8,%rdx), R32(%rcx)
jz L(shift_alot)
shr R8(%rcx), u0
L(ent): mov u0, %rax
mov v0, %rdx
sub u0, %rdx
sub v0, u0
jnz L(top)
L(end): C rax = result
C rdx = 0 for the benefit of internal gcd_22 call
FUNC_EXIT()
ret
L(shift_alot):
shr $MAXSHIFT, u0
mov u0, %rdx
jmp L(mid)
EPILOGUE()
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