;  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