mpir/mpn/x86_64/netburst/divexact_byff.as
2010-08-13 13:23:52 +00:00

83 lines
2.2 KiB
ActionScript

; core2 mpn_divexact_byff
; 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, rdx) = (rsi, rdx)/0xFFFFFFFFFFFFFFFF
; rax = "remainder"
; where (rsi, rdx) = (rdi, rdx)*(B - 1) -rax*B^rdx and 0 <= rax < B - 1 B = 0xFFFFFFFFFFFFFFFF
BITS 64
GLOBAL_FUNC mpn_divexact_byff
; this is good but suffers from alignment slowdown
; we dont seem to have much freedom to re-arrange the instructions to avoid
; it , I suppose we could detect alignment at the start and have different
; routines for different alignments
xor eax, eax
mov rcx, rdx
and rcx, 3
shr rdx, 2
cmp rdx, 0
; carry flag is clear here
jnz loop1
sbb rax, [rsi]
mov [rdi], rax
dec rcx
jz end1
sbb rax, [rsi+8]
mov [rdi+8], rax
dec rcx
jz end1
sbb rax, [rsi+16]
mov [rdi+16], rax
dec rcx
end1:
sbb rax, 0
ret
align 16
loop1:
sbb rax, [rsi]
mov [rdi], rax
sbb rax, [rsi+8]
mov [rdi+8], rax
sbb rax, [rsi+16]
mov [rdi+16], rax
sbb rax, [rsi+24]
mov [rdi+24], rax
lea rsi, [rsi+32]
dec rdx
lea rdi, [rdi+32]
jnz loop1
inc rcx
dec rcx
jz end
sbb rax, [rsi]
mov [rdi], rax
dec rcx
jz end
sbb rax, [rsi+8]
mov [rdi+8], rax
dec rcx
jz end
sbb rax, [rsi+16]
mov [rdi+16], rax
dec rcx
end:
sbb rax, 0
ret