;******************************************************************************
;* linear least squares model
;*
;* Copyright (c) 2013 Loren Merritt
;*
;* This file is part of FFmpeg.
;*
;* FFmpeg 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.
;*
;* FFmpeg 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 FFmpeg; if not, write to the Free Software
;* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;******************************************************************************

%include "libavutil/x86/x86util.asm"

SECTION .text

%define MAX_VARS 32
%define MAX_VARS_ALIGN (MAX_VARS+4)
%define COVAR_STRIDE MAX_VARS_ALIGN*8
%define COVAR(x,y) [covarq + (x)*8 + (y)*COVAR_STRIDE]

struc LLSModel
    .covariance:  resq MAX_VARS_ALIGN*MAX_VARS_ALIGN
    .coeff:       resq MAX_VARS*MAX_VARS
    .variance:    resq MAX_VARS
    .indep_count: resd 1
endstruc

%macro ADDPD_MEM 2
%if cpuflag(avx)
    vaddpd %2, %2, %1
%else
    addpd  %2, %1
%endif
    mova   %1, %2
%endmacro

INIT_XMM sse2
%define movdqa movaps
cglobal update_lls, 2,5,8, ctx, var, i, j, covar2
    %define covarq ctxq
    mov     id, [ctxq + LLSModel.indep_count]
    lea   varq, [varq + iq*8]
    neg     iq
    mov covar2q, covarq
.loopi:
    ; Compute all 3 pairwise products of a 2x2 block that lies on the diagonal
    mova    m1, [varq + iq*8]
    mova    m3, [varq + iq*8 + 16]
    pshufd  m4, m1, q1010
    pshufd  m5, m1, q3232
    pshufd  m6, m3, q1010
    pshufd  m7, m3, q3232
    mulpd   m0, m1, m4
    mulpd   m1, m1, m5
    lea covarq, [covar2q + 16]
    ADDPD_MEM COVAR(-2,0), m0
    ADDPD_MEM COVAR(-2,1), m1
    lea     jq, [iq + 2]
    cmp     jd, -2
    jg .skip4x4
.loop4x4:
    ; Compute all 16 pairwise products of a 4x4 block
    mulpd   m0, m4, m3
    mulpd   m1, m5, m3
    mulpd   m2, m6, m3
    mulpd   m3, m3, m7
    ADDPD_MEM COVAR(0,0), m0
    ADDPD_MEM COVAR(0,1), m1
    ADDPD_MEM COVAR(0,2), m2
    ADDPD_MEM COVAR(0,3), m3
    mova    m3, [varq + jq*8 + 16]
    mulpd   m0, m4, m3
    mulpd   m1, m5, m3
    mulpd   m2, m6, m3
    mulpd   m3, m3, m7
    ADDPD_MEM COVAR(2,0), m0
    ADDPD_MEM COVAR(2,1), m1
    ADDPD_MEM COVAR(2,2), m2
    ADDPD_MEM COVAR(2,3), m3
    mova    m3, [varq + jq*8 + 32]
    add covarq, 32
    add     jq, 4
    cmp     jd, -2
    jle .loop4x4
.skip4x4:
    test    jd, jd
    jg .skip2x4
    mulpd   m4, m3
    mulpd   m5, m3
    mulpd   m6, m3
    mulpd   m7, m3
    ADDPD_MEM COVAR(0,0), m4
    ADDPD_MEM COVAR(0,1), m5
    ADDPD_MEM COVAR(0,2), m6
    ADDPD_MEM COVAR(0,3), m7
.skip2x4:
    add     iq, 4
    add covar2q, 4*COVAR_STRIDE+32
    cmp     id, -2
    jle .loopi
    test    id, id
    jg .ret
    mov     jq, iq
    %define covarq covar2q
.loop2x1:
    movsd   m0, [varq + iq*8]
    movlhps m0, m0
    mulpd   m0, [varq + jq*8]
    ADDPD_MEM COVAR(0,0), m0
    inc     iq
    add covarq, COVAR_STRIDE
    test    id, id
    jle .loop2x1
.ret:
    RET

%macro UPDATE_LLS 0
cglobal update_lls, 3,6,8, ctx, var, count, i, j, count2
    %define covarq ctxq
    mov  countd, [ctxq + LLSModel.indep_count]
    lea count2d, [countq-2]
    xor     id, id
.loopi:
    ; Compute all 10 pairwise products of a 4x4 block that lies on the diagonal
    mova    ymm1, [varq + iq*8]
    vbroadcastsd ymm4, [varq + iq*8]
    vbroadcastsd ymm5, [varq + iq*8 + 8]
    vbroadcastsd ymm6, [varq + iq*8 + 16]
    vbroadcastsd ymm7, [varq + iq*8 + 24]
    vextractf128 xmm3, ymm1, 1
%if cpuflag(fma3)
    mova ymm0, COVAR(iq  ,0)
    mova xmm2, COVAR(iq+2,2)
    fmaddpd ymm0, ymm1, ymm4, ymm0
    fmaddpd xmm2, xmm3, xmm6, xmm2
    fmaddpd ymm1, ymm5, ymm1, COVAR(iq  ,1)
    fmaddpd xmm3, xmm7, xmm3, COVAR(iq+2,3)
    mova COVAR(iq  ,0), ymm0
    mova COVAR(iq  ,1), ymm1
    mova COVAR(iq+2,2), xmm2
    mova COVAR(iq+2,3), xmm3
%else
    vmulpd  ymm0, ymm1, ymm4
    vmulpd  ymm1, ymm1, ymm5
    vmulpd  xmm2, xmm3, xmm6
    vmulpd  xmm3, xmm3, xmm7
    ADDPD_MEM COVAR(iq  ,0), ymm0
    ADDPD_MEM COVAR(iq  ,1), ymm1
    ADDPD_MEM COVAR(iq+2,2), xmm2
    ADDPD_MEM COVAR(iq+2,3), xmm3
%endif ; cpuflag(fma3)
    lea     jd, [iq + 4]
    cmp     jd, count2d
    jg .skip4x4
.loop4x4:
    ; Compute all 16 pairwise products of a 4x4 block
    mova    ymm3, [varq + jq*8]
%if cpuflag(fma3)
    mova ymm0, COVAR(jq, 0)
    mova ymm1, COVAR(jq, 1)
    mova ymm2, COVAR(jq, 2)
    fmaddpd ymm0, ymm3, ymm4, ymm0
    fmaddpd ymm1, ymm3, ymm5, ymm1
    fmaddpd ymm2, ymm3, ymm6, ymm2
    fmaddpd ymm3, ymm7, ymm3, COVAR(jq,3)
    mova COVAR(jq, 0), ymm0
    mova COVAR(jq, 1), ymm1
    mova COVAR(jq, 2), ymm2
    mova COVAR(jq, 3), ymm3
%else
    vmulpd  ymm0, ymm3, ymm4
    vmulpd  ymm1, ymm3, ymm5
    vmulpd  ymm2, ymm3, ymm6
    vmulpd  ymm3, ymm3, ymm7
    ADDPD_MEM COVAR(jq,0), ymm0
    ADDPD_MEM COVAR(jq,1), ymm1
    ADDPD_MEM COVAR(jq,2), ymm2
    ADDPD_MEM COVAR(jq,3), ymm3
%endif ; cpuflag(fma3)
    add     jd, 4
    cmp     jd, count2d
    jle .loop4x4
.skip4x4:
    cmp     jd, countd
    jg .skip2x4
    mova    xmm3, [varq + jq*8]
%if cpuflag(fma3)
    mova xmm0, COVAR(jq, 0)
    mova xmm1, COVAR(jq, 1)
    mova xmm2, COVAR(jq, 2)
    fmaddpd xmm0, xmm3, xmm4, xmm0
    fmaddpd xmm1, xmm3, xmm5, xmm1
    fmaddpd xmm2, xmm3, xmm6, xmm2
    fmaddpd xmm3, xmm7, xmm3, COVAR(jq,3)
    mova COVAR(jq, 0), xmm0
    mova COVAR(jq, 1), xmm1
    mova COVAR(jq, 2), xmm2
    mova COVAR(jq, 3), xmm3
%else
    vmulpd  xmm0, xmm3, xmm4
    vmulpd  xmm1, xmm3, xmm5
    vmulpd  xmm2, xmm3, xmm6
    vmulpd  xmm3, xmm3, xmm7
    ADDPD_MEM COVAR(jq,0), xmm0
    ADDPD_MEM COVAR(jq,1), xmm1
    ADDPD_MEM COVAR(jq,2), xmm2
    ADDPD_MEM COVAR(jq,3), xmm3
%endif ; cpuflag(fma3)
.skip2x4:
    add     id, 4
    add covarq, 4*COVAR_STRIDE
    cmp     id, count2d
    jle .loopi
    cmp     id, countd
    jg .ret
    mov     jd, id
.loop2x1:
    vmovddup xmm0, [varq + iq*8]
%if cpuflag(fma3)
    mova xmm1, [varq + jq*8]
    fmaddpd xmm0, xmm1, xmm0, COVAR(jq,0)
    mova COVAR(jq,0), xmm0
%else
    vmulpd   xmm0, [varq + jq*8]
    ADDPD_MEM COVAR(jq,0), xmm0
%endif ; cpuflag(fma3)
    inc     id
    add covarq, COVAR_STRIDE
    cmp     id, countd
    jle .loop2x1
.ret:
    RET
%endmacro ; UPDATE_LLS

%if HAVE_AVX_EXTERNAL
INIT_YMM avx
UPDATE_LLS
%endif
%if HAVE_FMA3_EXTERNAL
INIT_YMM fma3
UPDATE_LLS
%endif

INIT_XMM sse2
cglobal evaluate_lls, 3,4,2, ctx, var, order, i
    ; This function is often called on the same buffer as update_lls, but with
    ; an offset. They can't both be aligned.
    ; Load halves rather than movu to avoid store-forwarding stalls, since the
    ; input was initialized immediately prior to this function using scalar math.
    %define coefsq ctxq
    mov     id, orderd
    imul    orderd, MAX_VARS
    lea     coefsq, [ctxq + LLSModel.coeff + orderq*8]
    movsd   m0, [varq]
    movhpd  m0, [varq + 8]
    mulpd   m0, [coefsq]
    lea coefsq, [coefsq + iq*8]
    lea   varq, [varq + iq*8]
    neg     iq
    add     iq, 2
.loop:
    movsd   m1, [varq + iq*8]
    movhpd  m1, [varq + iq*8 + 8]
    mulpd   m1, [coefsq + iq*8]
    addpd   m0, m1
    add     iq, 2
    jl .loop
    jg .skip1
    movsd   m1, [varq + iq*8]
    mulsd   m1, [coefsq + iq*8]
    addpd   m0, m1
.skip1:
    movhlps m1, m0
    addsd   m0, m1
%if ARCH_X86_32
    movsd  r0m, m0
    fld   qword r0m
%endif
    RET
