libvpx: Add VP9 decoder.

source/libvpx/vp9/encoder/ppc/vp9_encodemb_altivec.asm

+;
+;  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
+;
+;  Use of this source code is governed by a BSD-style license
+;  that can be found in the LICENSE file in the root of the source
+;  tree. An additional intellectual property rights grant can be found
+;  in the file PATENTS.  All contributing project authors may
+;  be found in the AUTHORS file in the root of the source tree.
+;
+
+
+    .globl vp8_subtract_mbuv_ppc
+    .globl vp8_subtract_mby_ppc
+
+;# r3 short *diff
+;# r4 unsigned char *usrc
+;# r5 unsigned char *vsrc
+;# r6 unsigned char *pred
+;# r7 int stride
+vp8_subtract_mbuv_ppc:
+    mfspr   r11, 256            ;# get old VRSAVE
+    oris    r12, r11, 0xf000
+    mtspr   256, r12            ;# set VRSAVE
+
+    li      r9, 256
+    add     r3, r3, r9
+    add     r3, r3, r9
+    add     r6, r6, r9
+
+    li      r10, 16
+    li      r9,  4
+    mtctr   r9
+
+    vspltisw v0, 0
+
+mbu_loop:
+    lvsl    v5, 0, r4           ;# permutate value for alignment
+    lvx     v1, 0, r4           ;# src
+    lvx     v2, 0, r6           ;# pred
+
+    add     r4, r4, r7
+    addi    r6, r6, 16
+
+    vperm   v1, v1, v0, v5
+
+    vmrghb  v3, v0, v1          ;# unpack high src  to short
+    vmrghb  v4, v0, v2          ;# unpack high pred to short
+
+    lvsl    v5, 0, r4           ;# permutate value for alignment
+    lvx     v1, 0, r4           ;# src
+
+    add     r4, r4, r7
+
+    vsubshs v3, v3, v4
+
+    stvx    v3, 0, r3           ;# store out diff
+
+    vperm   v1, v1, v0, v5
+
+    vmrghb  v3, v0, v1          ;# unpack high src  to short
+    vmrglb  v4, v0, v2          ;# unpack high pred to short
+
+    vsubshs v3, v3, v4
+
+    stvx    v3, r10, r3         ;# store out diff
+
+    addi    r3, r3, 32
+
+    bdnz    mbu_loop
+
+    mtctr   r9
+
+mbv_loop:
+    lvsl    v5, 0, r5           ;# permutate value for alignment
+    lvx     v1, 0, r5           ;# src
+    lvx     v2, 0, r6           ;# pred
+
+    add     r5, r5, r7
+    addi    r6, r6, 16
+
+    vperm   v1, v1, v0, v5
+
+    vmrghb  v3, v0, v1          ;# unpack high src  to short
+    vmrghb  v4, v0, v2          ;# unpack high pred to short
+
+    lvsl    v5, 0, r5           ;# permutate value for alignment
+    lvx     v1, 0, r5           ;# src
+
+    add     r5, r5, r7
+
+    vsubshs v3, v3, v4
+
+    stvx    v3, 0, r3           ;# store out diff
+
+    vperm   v1, v1, v0, v5
+
+    vmrghb  v3, v0, v1          ;# unpack high src  to short
+    vmrglb  v4, v0, v2          ;# unpack high pred to short
+
+    vsubshs v3, v3, v4
+
+    stvx    v3, r10, r3         ;# store out diff
+
+    addi    r3, r3, 32
+
+    bdnz    mbv_loop
+
+    mtspr   256, r11            ;# reset old VRSAVE
+
+    blr
+
+;# r3 short *diff
+;# r4 unsigned char *src
+;# r5 unsigned char *pred
+;# r6 int stride
+vp8_subtract_mby_ppc:
+    mfspr   r11, 256            ;# get old VRSAVE
+    oris    r12, r11, 0xf800
+    mtspr   256, r12            ;# set VRSAVE
+
+    li      r10, 16
+    mtctr   r10
+
+    vspltisw v0, 0
+
+mby_loop:
+    lvx     v1, 0, r4           ;# src
+    lvx     v2, 0, r5           ;# pred
+
+    add     r4, r4, r6
+    addi    r5, r5, 16
+
+    vmrghb  v3, v0, v1          ;# unpack high src  to short
+    vmrghb  v4, v0, v2          ;# unpack high pred to short
+
+    vsubshs v3, v3, v4
+
+    stvx    v3, 0, r3           ;# store out diff
+
+    vmrglb  v3, v0, v1          ;# unpack low src  to short
+    vmrglb  v4, v0, v2          ;# unpack low pred to short
+
+    vsubshs v3, v3, v4
+
+    stvx    v3, r10, r3         ;# store out diff
+
+    addi    r3, r3, 32
+
+    bdnz    mby_loop
+
+    mtspr   256, r11            ;# reset old VRSAVE
+
+    blr