mpir/mpn/x86_64w/divebyBm1of.asm
2009-04-14 17:35:03 +00:00

111 lines
2.8 KiB
NASM

; X86_64 mpn_diveby (B-1)/f
;
; Copyright 2008 Jason Moxham and 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 veSRCon.
; 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_divexact_byBm1of (
; mp_ptr dst, rcx
; mp_srcptr src, rdx
; mp_size_t len, r8
; mp_limb_t f r9
; mp_limb_t bm1of [rsp+ 0x28] = (B - 1) / f
; )
;
; dst[] = src[] / ((B - 1) / f)
;
; This is an SEH leaf function
%include "yasm_mac.inc"
%define CARRY_OUT
BITS 64
LEAF_PROC mpn_divexact_byBm1of
movsxd rax, r8d
mov r8, [rsp+0x28]
%ifdef CARRY_OUT
mov [rsp+0x20], r9 ; this needs changing if there is a carry in
%endif
lea r10, [rdx+rax*8-24]
lea r11, [rcx+rax*8-24]
mov ecx, 3
%ifdef CARRY_IN ; r9 is the carry in
imul r9, r8 ; this is needed if we have non-zero carry in
%else
mov r9, 0
%endif
sub rcx, rax
jnc .2
xalign 16
.1: mov rax, [r10+rcx*8]
mul r8
sub r9, rax
mov [r11+rcx*8], r9
sbb r9, rdx
mov rax, [r10+rcx*8+8]
mul r8
sub r9, rax
mov [r11+rcx*8+8], r9
sbb r9, rdx
mov rax, [r10+rcx*8+16]
mul r8
sub r9, rax
mov [r11+rcx*8+16], r9
sbb r9, rdx
mov rax, [r10+rcx*8+24]
mul r8
sub r9, rax
mov [r11+rcx*8+24], r9
sbb r9, rdx
add rcx, 4
jnc .1
.2: test rcx, 2
jnz .3
mov rax, [r10+rcx*8]
mul r8
sub r9, rax
mov [r11+rcx*8], r9
sbb r9, rdx
mov rax, [r10+rcx*8+8]
mul r8
sub r9, rax
mov [r11+rcx*8+8], r9
sbb r9, rdx
add rcx, 2
.3: test rcx, 1
jnz .4
mov rax, [r10+rcx*8]
mul r8
sub r9, rax
mov [r11+rcx*8], r9
sbb r9, rdx
.4:
%ifdef CARRY_OUT
imul r9, [rsp+0x20]
%endif
mov rax, r9
neg rax
ret
end