mpir/mpn/x86_64w/amd64/divebyff.asm

94 lines
2.2 KiB
NASM

; AMD64 mpn_divexact_byff
;
; 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_divexact_byff(
; mp_ptr dst, rcx
; mp_srcptr src, rdx
; mp_size_t size, r8
; )
;
; This is an SEH leaf function (no unwind support needed)
bits 64
section .text
global __gmpn_divexact_byff
%ifdef DLL
export __gmpn_divexact_byff
%endif
__gmpn_divexact_byff:
mov r8d, r8d
xor eax, eax
mov r9, r8
and r9, 3
shr r8, 2
cmp r8, 0
jnz .2 ; carry flag is clear here
sbb rax, [rdx]
mov [rcx], rax
dec r9
jz .1
sbb rax, [rdx+8]
mov [rcx+8], rax
dec r9
jz .1
sbb rax, [rdx+16]
mov [rcx+16], rax
dec r9
.1: sbb rax, 0
ret
alignb 16, nop
.2: sbb rax, [rdx]
mov [rcx], rax
sbb rax, [rdx+8]
mov [rcx+8], rax
sbb rax, [rdx+16]
mov [rcx+16], rax
sbb rax, [rdx+24]
mov [rcx+24], rax
lea rdx, [rdx+32]
dec r8
lea rcx, [rcx+32]
jnz .2
inc r9
dec r9
jz .3
sbb rax, [rdx]
mov [rcx], rax
dec r9
jz .3
sbb rax, [rdx+8]
mov [rcx+8], rax
dec r9
jz .3
sbb rax, [rdx+16]
mov [rcx+16], rax
dec r9
.3: sbb rax, 0
ret
end