mpir/mpn/x86_64w/amd64/rshift1.asm

124 lines
2.8 KiB
NASM

; AMD64 mpn_rshift1 -- mpn right shift by 1
; Version 1.0.4.
;
; Copyright 2008 Jason Moxham
;
; Windows Conversion Copyright 2008 Brian Gladman
;
; This file is part of the MPIR Library.
; The MPIR Library is free software; you can redistribute it and/or modify
; it under the terms of the GNU Lesser General Public License as published
; by the Free Software Foundation; either version 2.1 of the License, or (at
; your option) any later version.
; The MPIR Library is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
; or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
; License for more details.
; You should have received a copy of the GNU Lesser General Public License
; along with the MPIR Library; see the file COPYING.LIB. If not, write
; to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
; Boston, MA 02110-1301, USA.
;
; Calling interface:
;
; mp_limb_t mpn_rshift1(
; mp_ptr dst, rcx
; mp_srcptr src, rdx
; mp_size_t size, r8
; )
;
; This is an SEH leaf function (no unwind support needed)
%include "..\yasm_mac.inc"
BITS 64
%define reg_save_list r12, r13
FRAME_PROC mpn_rshift1, 0, reg_save_list
movsxd r8, r8d
xor rax, rax
lea rdx, [rdx+r8*8-8]
lea rcx, [rcx+r8*8-8]
mov r9, r8
and r9, 7
inc r9
shr r8, 3
; and clear carry flag
cmp r8, 0
jz .2
alignb 16, nop
.1: mov r10, [rdx]
mov r11, [rdx-8]
mov r12, [rdx-16]
mov r13, [rdx-24]
rcr r10, 1
rcr r11, 1
rcr r12, 1
rcr r13, 1
mov [rcx], r10
mov [rcx-8], r11
mov [rcx-16], r12
mov [rcx-24], r13
mov r10, [rdx-32]
mov r11, [rdx-40]
mov r12, [rdx-48]
mov r13, [rdx-56]
rcr r10, 1
rcr r11, 1
rcr r12, 1
rcr r13, 1
mov [rcx-32], r10
mov [rcx-40], r11
mov [rcx-48], r12
mov [rcx-56], r13
lea rdx, [rdx-64]
dec r8
lea rcx, [rcx-64]
jnz .1
.2: dec r9
jz .3
; Could suffer cache-bank conflicts in this tail part
mov r10, [rdx]
rcr r10, 1
mov [rcx], r10
dec r9
jz .3
mov r10, [rdx-8]
rcr r10, 1
mov [rcx-8], r10
dec r9
jz .3
mov r10, [rdx-16]
rcr r10, 1
mov [rcx-16], r10
dec r9
jz .3
mov r10, [rdx-24]
rcr r10, 1
mov [rcx-24], r10
dec r9
jz .3
mov r10, [rdx-32]
rcr r10, 1
mov [rcx-32], r10
dec r9
jz .3
mov r10, [rdx-40]
rcr r10, 1
mov [rcx-40], r10
dec r9
jz .3
mov r10, [rdx-48]
rcr r10, 1
mov [rcx-48], r10
.3: rcr rax, 1
END_PROC reg_save_list
end