aosp12/external/libhevc/common/arm64/ihevc_sao_edge_offset_class1.s

365 lines
20 KiB
ArmAsm

///*****************************************************************************
//*
//* Copyright (C) 2012 Ittiam Systems Pvt Ltd, Bangalore
//*
//* Licensed under the Apache License, Version 2.0 (the "License");
//* you may not use this file except in compliance with the License.
//* You may obtain a copy of the License at:
//*
//* http://www.apache.org/licenses/LICENSE-2.0
//*
//* Unless required by applicable law or agreed to in writing, software
//* distributed under the License is distributed on an "AS IS" BASIS,
//* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//* See the License for the specific language governing permissions and
//* limitations under the License.
//*
//*****************************************************************************/
///**
//*******************************************************************************
//* ,:file
//* ihevc_sao_edge_offset_class1.s
//*
//* ,:brief
//* Contains function definitions for inter prediction interpolation.
//* Functions are coded using NEON intrinsics and can be compiled using@ ARM
//* RVCT
//*
//* ,:author
//* Parthiban V
//*
//* ,:par List of Functions:
//*
//*
//* ,:remarks
//* None
//*
//*******************************************************************************
//*/
//void ihevc_sao_edge_offset_class1(UWORD8 *pu1_src,
// WORD32 src_strd,
// UWORD8 *pu1_src_left,
// UWORD8 *pu1_src_top,
// UWORD8 *pu1_src_top_left,
// UWORD8 *pu1_src_top_right,
// UWORD8 *pu1_src_bot_left,
// UWORD8 *pu1_avail,
// WORD8 *pi1_sao_offset,
// WORD32 wd,
// WORD32 ht)
//**************Variables Vs Registers*****************************************
//x0 => *pu1_src
//x1 => src_strd
//x2 => *pu1_src_left
//x3 => *pu1_src_top
//x4 => *pu1_src_top_left
//x5 => *pu1_avail
//x6 => *pi1_sao_offset
//x7 => wd
//x8 => ht
.text
.p2align 2
.include "ihevc_neon_macros.s"
.globl gi1_table_edge_idx
.globl ihevc_sao_edge_offset_class1_av8
ihevc_sao_edge_offset_class1_av8:
// STMFD sp!, {x4-x12, x14} //stack stores the values of the arguments
MOV x5,x7 //Loads pu1_avail
LDR x6,[sp] //Loads pi1_sao_offset
LDR w7,[sp,#8] //Loads wd
LDR w8,[sp,#16] //Loads ht
stp x19, x20,[sp,#-16]!
SUB x9,x7,#1 //wd - 1
LDRB w10,[x3,x9] //pu1_src_top[wd - 1]
STRB w10,[x4] //*pu1_src_top_left = pu1_src_top[wd - 1]
ADD x10,x0,x9 //pu1_src[row * src_strd + wd - 1]
MOV x11,x2 //Move pu1_src_left pointer to x11
MOV x12,x8 //Move ht to x12 for loop count
SRC_LEFT_LOOP:
LDRB w14,[x10] //Load pu1_src[row * src_strd + wd - 1]
ADD x10,x10,x1
STRB w14,[x11],#1 //pu1_src_left[row]
SUBS x12, x12,#1 //Decrement the loop count
BNE SRC_LEFT_LOOP //If not equal to 0 jump to the src_left_loop
SUB x12,x8,#1 //ht - 1
mul x12, x12, x1 //(ht - 1) * src_strd
ADD x12,x12,x0 //pu1_src[(ht - 1) * src_strd]
LDRB w4,[x5,#2] //pu1_avail[2]
CMP x4,#0 //0 == pu1_avail[2]
ADD x20,x0,x1 //pu1_src += src_strd
csel x0, x20, x0,EQ
SUB x20,x8,#1 //ht--
csel x8, x20, x8,EQ
LDRB w4,[x5,#3] //pu1_avail[3]
CMP x4,#0 //0 == pu1_avail[3]
SUB x20,x8,#1 //ht--
csel x8, x20, x8,EQ
movi v0.16b, #2 //const_2 = vdupq_n_s8(2)
movi v2.8h, #0 //const_min_clip = vdupq_n_s16(0)
movi v4.8h, #255 //const_max_clip = vdupq_n_u16((1 << bit_depth) - 1)
ADRP x14, :got:gi1_table_edge_idx //table pointer
LDR x14, [x14, #:got_lo12:gi1_table_edge_idx]
LD1 {v6.8b},[x14] //edge_idx_tbl = vld1_s8(gi1_table_edge_idx)
LD1 {v7.8b},[x6] //offset_tbl = vld1_s8(pi1_sao_offset)
CMP x7,#16 //Compare wd with 16
BLT WIDTH_RESIDUE //If not jump to WIDTH_RESIDUE where loop is unrolled for 8 case
WIDTH_LOOP_16:
LDRB w4,[x5,#2] //pu1_avail[2]
CMP x4,#0 //0 == pu1_avail[2]
SUB x20,x0,x1 //pu1_src -= src_strd
csel x9, x20, x9,EQ
csel x9, x3, x9,NE //*pu1_src_top
MOV x10,x0 //*pu1_src
LD1 {v1.16b},[x9],#16 //pu1_top_row = vld1q_u8(pu1_src_top_cpy || pu1_src - src_strd)
LD1 {v3.16b},[x0],#16 //pu1_cur_row = vld1q_u8(pu1_src)
LD1 {v30.16b},[x12],#16 //vld1q_u8(pu1_src[(ht - 1) * src_strd])
cmhi v5.16b, v3.16b , v1.16b //vcgtq_u8(pu1_cur_row, pu1_top_row)
ST1 { v30.16b},[x3],#16 //vst1q_u8(pu1_src_top[col])
cmhi v17.16b, v1.16b , v3.16b //vcltq_u8(pu1_cur_row, pu1_top_row)
SUB v16.16b, v17.16b , v5.16b //sign_up = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
MOV x11,x8 //move ht to x11 for loop count
PU1_SRC_LOOP:
ADD x10,x10,x1 //*pu1_src + src_strd
LD1 {v18.16b},[x10] //pu1_next_row = vld1q_u8(pu1_src_cpy + src_strd)
ADD x6,x10,x1 //II Iteration *pu1_src + src_strd
cmhi v5.16b, v3.16b , v18.16b //vcgtq_u8(pu1_cur_row, pu1_top_row)
LD1 {v30.16b},[x6] //II pu1_next_row = vld1q_u8(pu1_src_cpy + src_strd)
cmhi v17.16b, v18.16b , v3.16b //vcltq_u8(pu1_cur_row, pu1_top_row)
SUB x10,x10,x1
SUB v20.16b, v17.16b , v5.16b //sign_down = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
Uxtl v26.8h, v18.8b //II pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(pu1_cur_row)))
ADD v5.16b, v0.16b , v16.16b //edge_idx = vaddq_s8(const_2, sign_up)
Uxtl2 v28.8h, v18.16b //II pi2_tmp_cur_row.val[1] = vreinterpretq_s16_u16(vmovl_u8(vget_high_u8(pu1_cur_row)))
ADD v5.16b, v5.16b , v20.16b //edge_idx = vaddq_s8(edge_idx, sign_down)
cmhi v22.16b, v18.16b , v30.16b //II vcgtq_u8(pu1_cur_row, pu1_top_row)
NEG v16.16b, v20.16b //sign_up = vnegq_s8(sign_down)
TBL v5.16b, {v6.16b},v5.16b //vtbl1_s8(edge_idx_tbl, vget_low_s8(edge_idx))
cmhi v24.16b, v30.16b , v18.16b //II vcltq_u8(pu1_cur_row, pu1_top_row)
SUB v1.16b, v24.16b , v22.16b //II sign_down = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
// TBL v13.8b, {v6.16b},v13.8b //vtbl1_s8(edge_idx_tbl, vget_high_s8(edge_idx))
ADD v22.16b, v0.16b , v16.16b //II edge_idx = vaddq_s8(const_2, sign_up)
NEG v16.16b, v1.16b //II sign_up = vnegq_s8(sign_down)
TBL v5.16b, {v7.16b},v5.16b //offset = vtbl1_s8(offset_tbl, vget_low_s8(edge_idx))
ADD v22.16b, v22.16b , v1.16b //II edge_idx = vaddq_s8(edge_idx, sign_down)
Uxtl v20.8h, v3.8b //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(pu1_cur_row)))
TBL v22.16b, {v6.16b},v22.16b //II vtbl1_s8(edge_idx_tbl, vget_low_s8(edge_idx))
SADDW v20.8h, v20.8h , v5.8b //pi2_tmp_cur_row.val[0] = vaddw_s8(pi2_tmp_cur_row.val[0], offset)
SMAX v20.8h, v20.8h , v2.8h //pi2_tmp_cur_row.val[0] = vmaxq_s16(pi2_tmp_cur_row.val[0], const_min_clip)
// TBL v23.8b, {v6.16b},v23.8b //II vtbl1_s8(edge_idx_tbl, vget_high_s8(edge_idx))
UMIN v20.8h, v20.8h , v4.8h //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[0]), const_max_clip))
Uxtl2 v1.8h, v3.16b //pi2_tmp_cur_row.val[1] = vreinterpretq_s16_u16(vmovl_u8(vget_high_u8(pu1_cur_row)))
// TBL v13.8b, {v7.16b},v13.8b //offset = vtbl1_s8(offset_tbl, vget_high_s8(edge_idx))
mov v3.16b, v30.16b //II pu1_cur_row = pu1_next_row
SADDW2 v1.8h, v1.8h , v5.16b //pi2_tmp_cur_row.val[1] = vaddw_s8(pi2_tmp_cur_row.val[1], offset)
TBL v24.16b, {v7.16b},v22.16b //II offset = vtbl1_s8(offset_tbl, vget_low_s8(edge_idx))
SMAX v1.8h, v1.8h , v2.8h //pi2_tmp_cur_row.val[1] = vmaxq_s16(pi2_tmp_cur_row.val[1], const_min_clip)
UMIN v1.8h, v1.8h , v4.8h //pi2_tmp_cur_row.val[1] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[1]), const_max_clip))
// TBL v25.8b, {v7.16b},v23.8b //II offset = vtbl1_s8(offset_tbl, vget_high_s8(edge_idx))
xtn v20.8b, v20.8h //vmovn_s16(pi2_tmp_cur_row.val[0])
SADDW v26.8h, v26.8h , v24.8b //II pi2_tmp_cur_row.val[0] = vaddw_s8(pi2_tmp_cur_row.val[0], offset)
xtn2 v20.16b, v1.8h //vmovn_s16(pi2_tmp_cur_row.val[1])
SADDW2 v28.8h, v28.8h , v24.16b //II pi2_tmp_cur_row.val[1] = vaddw_s8(pi2_tmp_cur_row.val[1], offset)
SMAX v26.8h, v26.8h , v2.8h //II pi2_tmp_cur_row.val[0] = vmaxq_s16(pi2_tmp_cur_row.val[0], const_min_clip)
UMIN v26.8h, v26.8h , v4.8h //II pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[0]), const_max_clip))
SMAX v28.8h, v28.8h , v2.8h //II pi2_tmp_cur_row.val[1] = vmaxq_s16(pi2_tmp_cur_row.val[1], const_min_clip)
UMIN v28.8h, v28.8h , v4.8h //II pi2_tmp_cur_row.val[1] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[1]), const_max_clip))
ST1 { v20.16b},[x10],x1 //vst1q_u8(pu1_src_cpy, pu1_cur_row)
xtn v30.8b, v26.8h //II vmovn_s16(pi2_tmp_cur_row.val[0])
SUBS x11,x11,#2 //II Decrement the ht loop count by 1
xtn2 v30.16b, v28.8h //II vmovn_s16(pi2_tmp_cur_row.val[1])
ST1 { v30.16b},[x10],x1 //II vst1q_u8(pu1_src_cpy, pu1_cur_row)
BEQ PU1_SRC_LOOP_END //if 0 == pu1_avail[3] || 0 == pu1_avail[2] ht = ht--
CMP x11,#1 //checking any residue remains
BGT PU1_SRC_LOOP //If not equal jump to PU1_SRC_LOOP
ADD x10,x10,x1 //*pu1_src + src_strd
LD1 {v18.16b},[x10] //pu1_next_row = vld1q_u8(pu1_src_cpy + src_strd)
cmhi v5.16b, v3.16b , v18.16b //vcgtq_u8(pu1_cur_row, pu1_top_row)
cmhi v17.16b, v18.16b , v3.16b //vcltq_u8(pu1_cur_row, pu1_top_row)
SUB v20.16b, v17.16b , v5.16b //sign_down = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
SUB x10,x10,x1
ADD v22.16b, v0.16b , v16.16b //edge_idx = vaddq_s8(const_2, sign_up)
ADD v22.16b, v22.16b , v20.16b //edge_idx = vaddq_s8(edge_idx, sign_down)
TBL v22.16b, {v6.16b},v22.16b //vtbl1_s8(edge_idx_tbl, vget_low_s8(edge_idx))
// TBL v23.8b, {v6.16b},v23.8b //vtbl1_s8(edge_idx_tbl, vget_high_s8(edge_idx))
TBL v24.16b, {v7.16b},v22.16b //offset = vtbl1_s8(offset_tbl, vget_low_s8(edge_idx))
Uxtl v26.8h, v3.8b //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(pu1_cur_row)))
SADDW v26.8h, v26.8h , v24.8b //pi2_tmp_cur_row.val[0] = vaddw_s8(pi2_tmp_cur_row.val[0], offset)
SMAX v26.8h, v26.8h , v2.8h //pi2_tmp_cur_row.val[0] = vmaxq_s16(pi2_tmp_cur_row.val[0], const_min_clip)
UMIN v26.8h, v26.8h , v4.8h //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[0]), const_max_clip))
// TBL v25.8b, {v7.16b},v23.8b //offset = vtbl1_s8(offset_tbl, vget_high_s8(edge_idx))
Uxtl2 v28.8h, v3.16b //pi2_tmp_cur_row.val[1] = vreinterpretq_s16_u16(vmovl_u8(vget_high_u8(pu1_cur_row)))
SADDW2 v28.8h, v28.8h , v24.16b //pi2_tmp_cur_row.val[1] = vaddw_s8(pi2_tmp_cur_row.val[1], offset)
SMAX v28.8h, v28.8h , v2.8h //pi2_tmp_cur_row.val[1] = vmaxq_s16(pi2_tmp_cur_row.val[1], const_min_clip)
UMIN v28.8h, v28.8h , v4.8h //pi2_tmp_cur_row.val[1] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[1]), const_max_clip))
xtn v30.8b, v26.8h //vmovn_s16(pi2_tmp_cur_row.val[0])
xtn2 v30.16b, v28.8h //vmovn_s16(pi2_tmp_cur_row.val[1])
ST1 { v30.16b},[x10],x1 //vst1q_u8(pu1_src_cpy, pu1_cur_row)
PU1_SRC_LOOP_END:
mov v3.16b, v18.16b //pu1_cur_row = pu1_next_row
SUBS x7,x7,#16 //Decrement the wd loop count by 16
CMP x7,#8 //Check whether residue remains
BEQ WIDTH_RESIDUE //If residue remains jump to residue loop
BGT WIDTH_LOOP_16 //If not equal jump to width_loop
BLT END_LOOPS //Jump to end function
WIDTH_RESIDUE:
LDRB w4,[x5,#2] //pu1_avail[2]
CMP x4,#0 //0 == pu1_avail[2]
SUB x20,x0,x1 //pu1_src -= src_strd
csel x9, x20, x9,EQ
csel x9, x3, x9,NE //*pu1_src_top
MOV x10,x0
LD1 {v1.16b},[x9],#16 //pu1_top_row = vld1q_u8(pu1_src_top_cpy || pu1_src - src_strd)
LD1 {v3.16b},[x0],#16 //pu1_cur_row = vld1q_u8(pu1_src)
LD1 {v30.8b},[x12] //vld1_u8(pu1_src[(ht - 1) * src_strd])
ST1 {v30.8b},[x3] //vst1_u8(pu1_src_top[col])
cmhi v5.16b, v3.16b , v1.16b //vcgtq_u8(pu1_cur_row, pu1_top_row)
cmhi v17.16b, v1.16b , v3.16b //vcltq_u8(pu1_cur_row, pu1_top_row)
SUB v16.16b, v17.16b , v5.16b //sign_up = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
MOV x11,x8 //move ht to x11 for loop count
PU1_SRC_LOOP_RESIDUE:
ADD x10,x10,x1 //*pu1_src + src_strd
LD1 {v18.16b},[x10] //pu1_next_row = vld1q_u8(pu1_src_cpy + src_strd)
ADD x6,x10,x1 //II Iteration *pu1_src + src_strd
cmhi v5.16b, v3.16b , v18.16b //vcgtq_u8(pu1_cur_row, pu1_next_row)
LD1 {v30.16b},[x6] //II pu1_next_row = vld1q_u8(pu1_src_cpy + src_strd)
cmhi v17.16b, v18.16b , v3.16b //vcltq_u8(pu1_cur_row, pu1_next_row)
SUB x10,x10,x1
SUB v20.16b, v17.16b , v5.16b //sign_down = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
Uxtl v26.8h, v18.8b //II pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(pu1_cur_row)))
ADD v5.16b, v0.16b , v16.16b //edge_idx = vaddq_s8(const_2, sign_up)
cmhi v22.16b, v18.16b , v30.16b //II vcgtq_u8(pu1_cur_row, pu1_next_row)
ADD v5.16b, v5.16b , v20.16b //edge_idx = vaddq_s8(edge_idx, sign_down)
cmhi v24.16b, v30.16b , v18.16b //II vcltq_u8(pu1_cur_row, pu1_next_row)
NEG v16.16b, v20.16b //sign_up = vnegq_s8(sign_down)
TBL v5.8b, {v6.16b},v5.8b //vtbl1_s8(edge_idx_tbl, vget_low_s8(edge_idx))
SUB v20.16b, v24.16b , v22.16b //II sign_down = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
ADD v22.16b, v0.16b , v16.16b //II edge_idx = vaddq_s8(const_2, sign_up)
TBL v5.8b, {v7.16b},v5.8b //offset = vtbl1_s8(offset_tbl, vget_low_s8(edge_idx))
NEG v16.16b, v20.16b //II sign_up = vnegq_s8(sign_down)
ADD v22.16b, v22.16b , v20.16b //II edge_idx = vaddq_s8(edge_idx, sign_down)
Uxtl v20.8h, v3.8b //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(pu1_cur_row)))
SADDW v20.8h, v20.8h , v5.8b //pi2_tmp_cur_row.val[0] = vaddw_s8(pi2_tmp_cur_row.val[0], offset)
TBL v22.8b, {v6.16b},v22.8b //II vtbl1_s8(edge_idx_tbl, vget_low_s8(edge_idx))
SMAX v20.8h, v20.8h , v2.8h //pi2_tmp_cur_row.val[0] = vmaxq_s16(pi2_tmp_cur_row.val[0], const_min_clip)
UMIN v20.8h, v20.8h , v4.8h //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[0]), const_max_clip))
TBL v24.8b, {v7.16b},v22.8b //II offset = vtbl1_s8(offset_tbl, vget_low_s8(edge_idx))
xtn v20.8b, v20.8h //vmovn_s16(pi2_tmp_cur_row.val[0])
SADDW v26.8h, v26.8h , v24.8b //II pi2_tmp_cur_row.val[0] = vaddw_s8(pi2_tmp_cur_row.val[0], offset)
SMAX v26.8h, v26.8h , v2.8h //II pi2_tmp_cur_row.val[0] = vmaxq_s16(pi2_tmp_cur_row.val[0], const_min_clip)
UMIN v26.8h, v26.8h , v4.8h //II pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[0]), const_max_clip))
mov v3.16b, v30.16b //II pu1_cur_row = pu1_next_row
ST1 {v20.8b},[x10],x1 //vst1q_u8(pu1_src_cpy, pu1_cur_row)
xtn v30.8b, v26.8h //II vmovn_s16(pi2_tmp_cur_row.val[0])
SUBS x11,x11,#2 //Decrement the ht loop count by 1
ST1 {v30.8b},[x10],x1 //II vst1q_u8(pu1_src_cpy, pu1_cur_row)
BEQ END_LOOPS
CMP x11,#1
BGT PU1_SRC_LOOP_RESIDUE //If not equal jump to PU1_SRC_LOOP
ADD x10,x10,x1 //*pu1_src + src_strd
LD1 {v18.16b},[x10] //pu1_next_row = vld1q_u8(pu1_src_cpy + src_strd)
cmhi v5.16b, v3.16b , v18.16b //vcgtq_u8(pu1_cur_row, pu1_next_row)
cmhi v17.16b, v18.16b , v3.16b //vcltq_u8(pu1_cur_row, pu1_next_row)
SUB v20.16b, v17.16b , v5.16b //sign_down = vreinterpretq_s8_u8(vsubq_u8(cmp_lt, cmp_gt))
SUB x10,x10,x1
ADD v22.16b, v0.16b , v16.16b //edge_idx = vaddq_s8(const_2, sign_up)
ADD v22.16b, v22.16b , v20.16b //edge_idx = vaddq_s8(edge_idx, sign_down)
TBL v22.8b, {v6.16b},v22.8b //vtbl1_s8(edge_idx_tbl, vget_low_s8(edge_idx))
TBL v24.8b, {v7.16b},v22.8b //offset = vtbl1_s8(offset_tbl, vget_low_s8(edge_idx))
Uxtl v26.8h, v3.8b //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vmovl_u8(vget_low_u8(pu1_cur_row)))
SADDW v26.8h, v26.8h , v24.8b //pi2_tmp_cur_row.val[0] = vaddw_s8(pi2_tmp_cur_row.val[0], offset)
SMAX v26.8h, v26.8h , v2.8h //pi2_tmp_cur_row.val[0] = vmaxq_s16(pi2_tmp_cur_row.val[0], const_min_clip)
UMIN v26.8h, v26.8h , v4.8h //pi2_tmp_cur_row.val[0] = vreinterpretq_s16_u16(vminq_u16(vreinterpretq_u16_s16(pi2_tmp_cur_row.val[0]), const_max_clip))
xtn v30.8b, v26.8h //vmovn_s16(pi2_tmp_cur_row.val[0])
ST1 {v30.8b},[x10],x1 //vst1q_u8(pu1_src_cpy, pu1_cur_row)
END_LOOPS:
// LDMFD sp!,{x4-x12,x15} //Reload the registers from SP
ldp x19, x20,[sp], #16
ret