;  AMD64 mpn_rshift1
;  Copyright 2008 Jason Moxham
;  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.

;	(rdi,rdx) = (rsi,rdx)>>1
;	rax = carry

%include '../yasm_mac.inc'

    BITS    64

   GLOBAL_FUNC mpn_rshift1
	xor     rax, rax
	lea     rsi, [rsi+rdx*8-8]
	lea     rdi, [rdi+rdx*8-8]
	mov     r11, rdx
	and     r11, 7
	inc     r11
	shr     rdx, 3
;	and clear carry flag
	cmp     rdx, 0
	jz      next
	align   16
loop1:
	mov     rcx, [rsi]
	mov     r8, [rsi-8]
	mov     r9, [rsi-16]
	mov     r10, [rsi-24]
	rcr     rcx, 1
	rcr     r8, 1
	rcr     r9, 1
	rcr     r10, 1
	mov     [rdi], rcx
	mov     [rdi-8], r8
	mov     [rdi-16], r9
	mov     [rdi-24], r10
	mov     rcx, [rsi-32]
	mov     r8, [rsi-40]
	mov     r9, [rsi-48]
	mov     r10, [rsi-56]
	rcr     rcx, 1
	rcr     r8, 1
	rcr     r9, 1
	rcr     r10, 1
	mov     [rdi-32], rcx
	mov     [rdi-40], r8
	mov     [rdi-48], r9
	mov     [rdi-56], r10
	lea     rsi, [rsi-64]
	dec     rdx
	lea     rdi, [rdi-64]
	jnz     loop1
next:
	dec     r11
	jz      end
;	Could suffer cache-bank conflicts in this tail part
	mov     rcx, [rsi]
	rcr     rcx, 1
	mov     [rdi], rcx
	dec     r11
	jz      end
	mov     rcx, [rsi-8]
	rcr     rcx, 1
	mov     [rdi-8], rcx
	dec     r11
	jz      end
	mov     rcx, [rsi-16]
	rcr     rcx, 1
	mov     [rdi-16], rcx
	dec     r11
	jz      end
	mov     rcx, [rsi-24]
	rcr     rcx, 1
	mov     [rdi-24], rcx
	dec     r11
	jz      end
	mov     rcx, [rsi-32]
	rcr     rcx, 1
	mov     [rdi-32], rcx
	dec     r11
	jz      end
	mov     rcx, [rsi-40]
	rcr     rcx, 1
	mov     [rdi-40], rcx
	dec     r11
	jz      end
	mov     rcx, [rsi-48]
	rcr     rcx, 1
	mov     [rdi-48], rcx
end:
	rcr     rax, 1
	ret