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@
@ Copyright (c) 2011 The WebRTC 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.
@
@ Contains a function for the core loop in the normalized lattice AR
@ filter routine for iSAC codec, optimized for ARMv7 platforms.
@
@ Output is bit-exact with the reference C code in lattic_c.c
@
@ Register usage:
@
@ r0: &ar_g_Q0
@ r1: &ar_f_Q0
@ r2: &cth_Q15
@ r3: &sth_Q15
@ r4: out loop counter
@ r5: tmpAR
@ r9: inner loop counter
@ r12: constant #16384
@ r6, r7, r8, r10, r11: scratch
#include "webrtc/system_wrappers/interface/asm_defines.h"
#include "settings.h"
GLOBAL_FUNCTION WebRtcIsacfix_FilterArLoop
.align 2
DEFINE_FUNCTION WebRtcIsacfix_FilterArLoop
push {r4-r11}
add r1, #2 @ &ar_f_Q0[1]
mov r12, #16384
mov r4, #HALF_SUBFRAMELEN
sub r4, #1 @ Outer loop counter = HALF_SUBFRAMELEN - 1
HALF_SUBFRAME_LOOP: @ for (n = 0; n < HALF_SUBFRAMELEN - 1; n++)
ldr r9, [sp, #32] @ Restore the inner loop counter to order_coef
ldrh r5, [r1] @ tmpAR = ar_f_Q0[n+1]
add r0, r9, asl #1 @ Restore r0 to &ar_g_Q0[order_coef]
add r2, r9, asl #1 @ Restore r2 to &cth_Q15[order_coef]
add r3, r9, asl #1 @ Restore r3 to &sth_Q15[order_coef]
ORDER_COEF_LOOP: @ for (k = order_coef; k > 0; k--)
ldrh r7, [r3, #-2]! @ sth_Q15[k - 1]
ldrh r6, [r2, #-2]! @ cth_Q15[k - 1]
ldrh r8, [r0, #-2] @ ar_g_Q0[k - 1]
smlabb r11, r7, r5, r12 @ sth_Q15[k - 1] * tmpAR + 16384
smlabb r10, r6, r5, r12 @ cth_Q15[k - 1] * tmpAR + 16384
smulbb r7, r7, r8 @ sth_Q15[k - 1] * ar_g_Q0[k - 1]
smlabb r11, r6, r8, r11 @ cth_Q15[k - 1] * ar_g_Q0[k - 1] +
@ (sth_Q15[k - 1] * tmpAR + 16384)
sub r10, r10, r7 @ cth_Q15[k - 1] * tmpAR + 16384 -
@ (sth_Q15[k - 1] * ar_g_Q0[k - 1])
ssat r11, #16, r11, asr #15
ssat r5, #16, r10, asr #15
strh r11, [r0], #-2 @ Output: ar_g_Q0[k]
subs r9, #1
bgt ORDER_COEF_LOOP
strh r5, [r0] @ Output: ar_g_Q0[0] = tmpAR;
strh r5, [r1], #2 @ Output: ar_f_Q0[n+1] = tmpAR;
subs r4, #1
bne HALF_SUBFRAME_LOOP
pop {r4-r11}
bx lr
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