mpir/mpn/x86_64/k8/rsh1sub_n.as

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; AMD64 mpn_rsh1sub_n
; Copyright 2009 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.
%include 'yasm_mac.inc'
; (rdi,rcx)=((rsi,rcx)-(rdx,rcx))/2
; return bottom bit of difference
; subtraction treated as two compliment
GLOBAL_FUNC mpn_rsh1sub_n
lea rdi, [rdi+rcx*8-32]
lea rsi, [rsi+rcx*8-32]
lea rdx, [rdx+rcx*8-32]
push r12
push rbx
mov r8, 4
sub r8, rcx
mov r12, [rsi+r8*8]
sub r12, [rdx+r8*8]
sbb rbx, rbx
mov rax, r12
and rax, 1
cmp r8, 0
jge L_skiplp
L_lp:
mov r11, [rsi+r8*8+32]
mov r10, [rsi+r8*8+24]
add rbx, 1
mov rcx, [rsi+r8*8+8]
mov r9, [rsi+r8*8+16]
sbb rcx, [rdx+r8*8+8]
sbb r9, [rdx+r8*8+16]
sbb r10, [rdx+r8*8+24]
sbb r11, [rdx+r8*8+32]
sbb rbx, rbx
bt r11, 0
rcr r10, 1
rcr r9, 1
rcr rcx, 1
rcr r12, 1
mov [rdi+r8*8], r12
mov [rdi+r8*8+8], rcx
mov [rdi+r8*8+16], r9
mov [rdi+r8*8+24], r10
mov r12, r11
add r8, 4
jnc L_lp
L_skiplp:
cmp r8, 2
ja L_case0
jz L_case1
jp L_case2
L_case3:
mov r10, [rsi+r8*8+24]
add rbx, 1
mov rcx, [rsi+r8*8+8]
mov r9, [rsi+r8*8+16]
sbb rcx, [rdx+r8*8+8]
sbb r9, [rdx+r8*8+16]
sbb r10, [rdx+r8*8+24]
rcr r10, 1
rcr r9, 1
rcr rcx, 1
rcr r12, 1
mov [rdi+r8*8], r12
mov [rdi+r8*8+8], rcx
mov [rdi+r8*8+16], r9
mov [rdi+r8*8+24], r10
pop rbx
pop r12
ret
align 16
L_case2:
add rbx, 1
mov rcx, [rsi+r8*8+8]
mov r9, [rsi+r8*8+16]
sbb rcx, [rdx+r8*8+8]
sbb r9, [rdx+r8*8+16]
rcr r9, 1
rcr rcx, 1
rcr r12, 1
mov [rdi+r8*8], r12
mov [rdi+r8*8+8], rcx
mov [rdi+r8*8+16], r9
pop rbx
pop r12
ret
align 16
L_case1:
add rbx, 1
mov rcx, [rsi+r8*8+8]
sbb rcx, [rdx+r8*8+8]
rcr rcx, 1
rcr r12, 1
mov [rdi+r8*8], r12
mov [rdi+r8*8+8], rcx
pop rbx
pop r12
ret
align 16
L_case0:
add rbx, 1
rcr r12, 1
mov [rdi+r8*8], r12
pop rbx
pop r12
ret
end