ref: d68e809bf8310e215c47bc334edb7d9207ed1bc5
dir: /celt/arm/celt_pitch_xcorr_arm.s/
; Copyright (c) 2007-2008 CSIRO
; Copyright (c) 2007-2009 Xiph.Org Foundation
; Copyright (c) 2013 Parrot
; Written by Aurélien Zanelli
;
; Redistribution and use in source and binary forms, with or without
; modification, are permitted provided that the following conditions
; are met:
;
; - Redistributions of source code must retain the above copyright
; notice, this list of conditions and the following disclaimer.
;
; - Redistributions in binary form must reproduce the above copyright
; notice, this list of conditions and the following disclaimer in the
; documentation and/or other materials provided with the distribution.
;
; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
; ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
; A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
; OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
; EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
; PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
; PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
; LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
; NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
; SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
AREA |.text|, CODE, READONLY
GET celt/arm/armopts.s
IF OPUS_ARM_MAY_HAVE_EDSP
EXPORT celt_pitch_xcorr_edsp
ENDIF
IF OPUS_ARM_MAY_HAVE_NEON
EXPORT celt_pitch_xcorr_neon
ENDIF
IF OPUS_ARM_MAY_HAVE_NEON
; Compute sum[k]=sum(x[j]*y[j+k],j=0...len-1), k=0...3
xcorr_kernel_neon PROC
xcorr_kernel_neon_start
; input:
; r3 = int len
; r4 = opus_val16 *x
; r5 = opus_val16 *y
; q0 = opus_val32 sum[4]
; output:
; q0 = opus_val32 sum[4]
; preserved: r0-r3, r6-r11, d2, q4-q7, q9-q15
; internal usage:
; r12 = int j
; d3 = y_3|y_2|y_1|y_0
; q2 = y_B|y_A|y_9|y_8|y_7|y_6|y_5|y_4
; q3 = x_7|x_6|x_5|x_4|x_3|x_2|x_1|x_0
; q8 = scratch
;
; Load y[0...3]
; This requires len>0 to always be valid (which we assert in the C code).
VLD1.16 {d5}, [r5]!
SUBS r12, r3, #8
BLE xcorr_kernel_neon_process4
; Process 8 samples at a time.
; This loop loads one y value more than we actually need. Therefore we have to
; stop as soon as there are 8 or fewer samples left (instead of 7), to avoid
; reading past the end of the array.
xcorr_kernel_neon_process8
; This loop has 19 total instructions (10 cycles to issue, minimum), with
; - 2 cycles of ARM insrtuctions,
; - 10 cycles of load/store/byte permute instructions, and
; - 9 cycles of data processing instructions.
; On a Cortex A8, we dual-issue the maximum amount (9 cycles) between the
; latter two categories, meaning the whole loop should run in 10 cycles per
; iteration, barring cache misses.
;
; Load x[0...7]
VLD1.16 {d6, d7}, [r4]!
; Unlike VMOV, VAND is a data processsing instruction (and doesn't get
; assembled to VMOV, like VORR would), so it dual-issues with the prior VLD1.
VAND d3, d5, d5
SUBS r12, r12, #8
; Load y[4...11]
VLD1.16 {d4, d5}, [r5]!
VMLAL.S16 q0, d3, d6[0]
VEXT.16 d16, d3, d4, #1
VMLAL.S16 q0, d4, d7[0]
VEXT.16 d17, d4, d5, #1
VMLAL.S16 q0, d16, d6[1]
VEXT.16 d16, d3, d4, #2
VMLAL.S16 q0, d17, d7[1]
VEXT.16 d17, d4, d5, #2
VMLAL.S16 q0, d16, d6[2]
VEXT.16 d16, d3, d4, #3
VMLAL.S16 q0, d17, d7[2]
VEXT.16 d17, d4, d5, #3
VMLAL.S16 q0, d16, d6[3]
VMLAL.S16 q0, d17, d7[3]
BGT xcorr_kernel_neon_process8
; Process 4 samples here if we have > 4 left (still reading one extra y value).
xcorr_kernel_neon_process4
ADDS r12, r12, #4
BLE xcorr_kernel_neon_process2
; Load x[0...3]
VLD1.16 d6, [r4]!
; Use VAND since it's a data processing instruction again.
VAND d4, d5, d5
SUB r12, r12, #4
; Load y[4...7]
VLD1.16 d5, [r5]!
VMLAL.S16 q0, d4, d6[0]
VEXT.16 d16, d4, d5, #1
VMLAL.S16 q0, d16, d6[1]
VEXT.16 d16, d4, d5, #2
VMLAL.S16 q0, d16, d6[2]
VEXT.16 d16, d4, d5, #3
VMLAL.S16 q0, d16, d6[3]
; Process 2 samples here if we have > 2 left (still reading one extra y value).
xcorr_kernel_neon_process2
ADDS r12, r12, #2
BLE xcorr_kernel_neon_process1
; Load x[0...1]
VLD2.16 {d6[],d7[]}, [r4]!
; Use VAND since it's a data processing instruction again.
VAND d4, d5, d5
SUB r12, r12, #2
; Load y[4...5]
VLD1.32 {d5[]}, [r5]!
VMLAL.S16 q0, d4, d6
VEXT.16 d16, d4, d5, #1
; Replace bottom copy of {y5,y4} in d5 with {y3,y2} from d4, using VSRI
; instead of VEXT, since it's a data-processing instruction.
VSRI.64 d5, d4, #32
VMLAL.S16 q0, d16, d7
; Process 1 sample using the extra y value we loaded above.
xcorr_kernel_neon_process1
; Load next *x
VLD1.16 {d6[]}, [r4]!
ADDS r12, r12, #1
; y[0...3] are left in d5 from prior iteration(s) (if any)
VMLAL.S16 q0, d5, d6
MOVLE pc, lr
; Now process 1 last sample, not reading ahead.
; Load last *y
VLD1.16 {d4[]}, [r5]!
VSRI.64 d4, d5, #16
; Load last *x
VLD1.16 {d6[]}, [r4]!
VMLAL.S16 q0, d4, d6
MOV pc, lr
ENDP
; opus_val32 celt_pitch_xcorr_neon(opus_val16 *_x, opus_val16 *_y,
; opus_val32 *xcorr, int len, int max_pitch)
celt_pitch_xcorr_neon PROC
; input:
; r0 = opus_val16 *_x
; r1 = opus_val16 *_y
; r2 = opus_val32 *xcorr
; r3 = int len
; output:
; r0 = int maxcorr
; internal usage:
; r4 = opus_val16 *x (for xcorr_kernel_neon())
; r5 = opus_val16 *y (for xcorr_kernel_neon())
; r6 = int max_pitch
; r12 = int j
; q15 = int maxcorr[4] (q15 is not used by xcorr_kernel_neon())
STMFD sp!, {r4-r6, lr}
LDR r6, [sp, #16]
VMOV.S32 q15, #1
; if (max_pitch < 4) goto celt_pitch_xcorr_neon_process4_done
SUBS r6, r6, #4
BLT celt_pitch_xcorr_neon_process4_done
celt_pitch_xcorr_neon_process4
; xcorr_kernel_neon parameters:
; r3 = len, r4 = _x, r5 = _y, q0 = {0, 0, 0, 0}
MOV r4, r0
MOV r5, r1
VEOR q0, q0, q0
; xcorr_kernel_neon only modifies r4, r5, r12, and q0...q3.
; So we don't save/restore any other registers.
BL xcorr_kernel_neon_start
SUBS r6, r6, #4
VST1.32 {q0}, [r2]!
; _y += 4
ADD r1, r1, #8
VMAX.S32 q15, q15, q0
; if (max_pitch < 4) goto celt_pitch_xcorr_neon_process4_done
BGE celt_pitch_xcorr_neon_process4
; We have less than 4 sums left to compute.
celt_pitch_xcorr_neon_process4_done
ADDS r6, r6, #4
; Reduce maxcorr to a single value
VMAX.S32 d30, d30, d31
VPMAX.S32 d30, d30, d30
; if (max_pitch <= 0) goto celt_pitch_xcorr_neon_done
BLE celt_pitch_xcorr_neon_done
; Now compute each remaining sum one at a time.
celt_pitch_xcorr_neon_process_remaining
MOV r4, r0
MOV r5, r1
VMOV.I32 q0, #0
SUBS r12, r3, #8
BLT celt_pitch_xcorr_neon_process_remaining4
; Sum terms 8 at a time.
celt_pitch_xcorr_neon_process_remaining_loop8
; Load x[0...7]
VLD1.16 {q1}, [r4]!
; Load y[0...7]
VLD1.16 {q2}, [r5]!
SUBS r12, r12, #8
VMLAL.S16 q0, d4, d2
VMLAL.S16 q0, d5, d3
BGE celt_pitch_xcorr_neon_process_remaining_loop8
; Sum terms 4 at a time.
celt_pitch_xcorr_neon_process_remaining4
ADDS r12, r12, #4
BLT celt_pitch_xcorr_neon_process_remaining4_done
; Load x[0...3]
VLD1.16 {d2}, [r4]!
; Load y[0...3]
VLD1.16 {d3}, [r5]!
SUB r12, r12, #4
VMLAL.S16 q0, d3, d2
celt_pitch_xcorr_neon_process_remaining4_done
; Reduce the sum to a single value.
VADD.S32 d0, d0, d1
VPADDL.S32 d0, d0
ADDS r12, r12, #4
BLE celt_pitch_xcorr_neon_process_remaining_loop_done
; Sum terms 1 at a time.
celt_pitch_xcorr_neon_process_remaining_loop1
VLD1.16 {d2[]}, [r4]!
VLD1.16 {d3[]}, [r5]!
SUBS r12, r12, #1
VMLAL.S16 q0, d2, d3
BGT celt_pitch_xcorr_neon_process_remaining_loop1
celt_pitch_xcorr_neon_process_remaining_loop_done
VST1.32 {d0[0]}, [r2]!
VMAX.S32 d30, d30, d0
SUBS r6, r6, #1
; _y++
ADD r1, r1, #2
; if (--max_pitch > 0) goto celt_pitch_xcorr_neon_process_remaining
BGT celt_pitch_xcorr_neon_process_remaining
celt_pitch_xcorr_neon_done
VMOV.32 r0, d30[0]
LDMFD sp!, {r4-r6, pc}
ENDP
ENDIF
IF OPUS_ARM_MAY_HAVE_EDSP
; This will get used on ARMv7 devices without NEON, so it has been optimized
; to take advantage of dual-issuing where possible.
xcorr_kernel_edsp PROC
xcorr_kernel_edsp_start
; input:
; r3 = int len
; r4 = opus_val16 *_x (must be 32-bit aligned)
; r5 = opus_val16 *_y (must be 32-bit aligned)
; r6...r9 = opus_val32 sum[4]
; output:
; r6...r9 = opus_val32 sum[4]
; preserved: r0-r5
; internal usage
; r2 = int j
; r12,r14 = opus_val16 x[4]
; r10,r11 = opus_val16 y[4]
STMFD sp!, {r2,r4,r5,lr}
LDR r10, [r5], #4 ; Load y[0...1]
SUBS r2, r3, #4 ; j = len-4
LDR r11, [r5], #4 ; Load y[2...3]
BLE xcorr_kernel_edsp_process4_done
LDR r12, [r4], #4 ; Load x[0...1]
; Stall
xcorr_kernel_edsp_process4
; The multiplies must issue from pipeline 0, and can't dual-issue with each
; other. Every other instruction here dual-issues with a multiply, and is
; thus "free". There should be no stalls in the body of the loop.
SMLABB r6, r12, r10, r6 ; sum[0] = MAC16_16(sum[0],x_0,y_0)
LDR r14, [r4], #4 ; Load x[2...3]
SMLABT r7, r12, r10, r7 ; sum[1] = MAC16_16(sum[1],x_0,y_1)
SUBS r2, r2, #4 ; j-=4
SMLABB r8, r12, r11, r8 ; sum[2] = MAC16_16(sum[2],x_0,y_2)
SMLABT r9, r12, r11, r9 ; sum[3] = MAC16_16(sum[3],x_0,y_3)
SMLATT r6, r12, r10, r6 ; sum[0] = MAC16_16(sum[0],x_1,y_1)
LDR r10, [r5], #4 ; Load y[4...5]
SMLATB r7, r12, r11, r7 ; sum[1] = MAC16_16(sum[1],x_1,y_2)
SMLATT r8, r12, r11, r8 ; sum[2] = MAC16_16(sum[2],x_1,y_3)
SMLATB r9, r12, r10, r9 ; sum[3] = MAC16_16(sum[3],x_1,y_4)
LDRGT r12, [r4], #4 ; Load x[0...1]
SMLABB r6, r14, r11, r6 ; sum[0] = MAC16_16(sum[0],x_2,y_2)
SMLABT r7, r14, r11, r7 ; sum[1] = MAC16_16(sum[1],x_2,y_3)
SMLABB r8, r14, r10, r8 ; sum[2] = MAC16_16(sum[2],x_2,y_4)
SMLABT r9, r14, r10, r9 ; sum[3] = MAC16_16(sum[3],x_2,y_5)
SMLATT r6, r14, r11, r6 ; sum[0] = MAC16_16(sum[0],x_3,y_3)
LDR r11, [r5], #4 ; Load y[6...7]
SMLATB r7, r14, r10, r7 ; sum[1] = MAC16_16(sum[1],x_3,y_4)
SMLATT r8, r14, r10, r8 ; sum[2] = MAC16_16(sum[2],x_3,y_5)
SMLATB r9, r14, r11, r9 ; sum[3] = MAC16_16(sum[3],x_3,y_6)
BGT xcorr_kernel_edsp_process4
xcorr_kernel_edsp_process4_done
ADDS r2, r2, #4
BLE xcorr_kernel_edsp_done
LDRH r12, [r4], #2 ; r12 = *x++
SUBS r2, r2, #1 ; j--
; Stall
SMLABB r6, r12, r10, r6 ; sum[0] = MAC16_16(sum[0],x,y_0)
LDRHGT r14, [r4], #2 ; r14 = *x++
SMLABT r7, r12, r10, r7 ; sum[1] = MAC16_16(sum[1],x,y_1)
SMLABB r8, r12, r11, r8 ; sum[2] = MAC16_16(sum[2],x,y_2)
SMLABT r9, r12, r11, r9 ; sum[3] = MAC16_16(sum[3],x,y_3)
BLE xcorr_kernel_edsp_done
SMLABT r6, r14, r10, r6 ; sum[0] = MAC16_16(sum[0],x,y_1)
SUBS r2, r2, #1 ; j--
SMLABB r7, r14, r11, r7 ; sum[1] = MAC16_16(sum[1],x,y_2)
LDRH r10, [r5], #2 ; r10 = y_4 = *y++
SMLABT r8, r14, r11, r8 ; sum[2] = MAC16_16(sum[2],x,y_3)
LDRHGT r12, [r4], #2 ; r12 = *x++
SMLABB r9, r14, r10, r9 ; sum[3] = MAC16_16(sum[3],x,y_4)
BLE xcorr_kernel_edsp_done
SMLABB r6, r12, r11, r6 ; sum[0] = MAC16_16(sum[0],tmp,y_2)
CMP r2, #1 ; j--
SMLABT r7, r12, r11, r7 ; sum[1] = MAC16_16(sum[1],tmp,y_3)
LDRH r2, [r5], #2 ; r2 = y_5 = *y++
SMLABB r8, r12, r10, r8 ; sum[2] = MAC16_16(sum[2],tmp,y_4)
LDRHGT r14, [r4] ; r14 = *x
SMLABB r9, r12, r2, r9 ; sum[3] = MAC16_16(sum[3],tmp,y_5)
BLE xcorr_kernel_edsp_done
SMLABT r6, r14, r11, r6 ; sum[0] = MAC16_16(sum[0],tmp,y_3)
LDRH r11, [r5] ; r11 = y_6 = *y
SMLABB r7, r14, r10, r7 ; sum[1] = MAC16_16(sum[1],tmp,y_4)
SMLABB r8, r14, r2, r8 ; sum[2] = MAC16_16(sum[2],tmp,y_5)
SMLABB r9, r14, r11, r9 ; sum[3] = MAC16_16(sum[3],tmp,y_6)
xcorr_kernel_edsp_done
LDMFD sp!, {r2,r4,r5,pc}
ENDP
celt_pitch_xcorr_edsp PROC
; input:
; r0 = opus_val16 *_x (must be 32-bit aligned)
; r1 = opus_val16 *_y (only needs to be 16-bit aligned)
; r2 = opus_val32 *xcorr
; r3 = int len
; output:
; r0 = maxcorr
; internal usage
; r4 = opus_val16 *x
; r5 = opus_val16 *y
; r6 = opus_val32 sum0
; r7 = opus_val32 sum1
; r8 = opus_val32 sum2
; r9 = opus_val32 sum3
; r1 = int max_pitch
; r12 = int j
STMFD sp!, {r4-r11, lr}
MOV r5, r1
LDR r1, [sp, #36]
MOV r4, r0
TST r5, #3
; maxcorr = 1
MOV r0, #1
BEQ celt_pitch_xcorr_edsp_process1u_done
; Compute one sum at the start to make y 32-bit aligned.
SUBS r12, r3, #4
; r14 = sum = 0
MOV r14, #0
LDRH r8, [r5], #2
BLE celt_pitch_xcorr_edsp_process1u_loop4_done
LDR r6, [r4], #4
MOV r8, r8, LSL #16
celt_pitch_xcorr_edsp_process1u_loop4
LDR r9, [r5], #4
SMLABT r14, r6, r8, r14 ; sum = MAC16_16(sum, x_0, y_0)
LDR r7, [r4], #4
SMLATB r14, r6, r9, r14 ; sum = MAC16_16(sum, x_1, y_1)
LDR r8, [r5], #4
SMLABT r14, r7, r9, r14 ; sum = MAC16_16(sum, x_2, y_2)
SUBS r12, r12, #4 ; j-=4
SMLATB r14, r7, r8, r14 ; sum = MAC16_16(sum, x_3, y_3)
LDRGT r6, [r4], #4
BGT celt_pitch_xcorr_edsp_process1u_loop4
MOV r8, r8, LSR #16
celt_pitch_xcorr_edsp_process1u_loop4_done
ADDS r12, r12, #4
celt_pitch_xcorr_edsp_process1u_loop1
LDRHGE r6, [r4], #2
; Stall
SMLABBGE r14, r6, r8, r14 ; sum = MAC16_16(sum, *x, *y)
SUBSGE r12, r12, #1
LDRHGT r8, [r5], #2
BGT celt_pitch_xcorr_edsp_process1u_loop1
; Restore _x
SUB r4, r4, r3, LSL #1
; Restore and advance _y
SUB r5, r5, r3, LSL #1
; maxcorr = max(maxcorr, sum)
CMP r0, r14
ADD r5, r5, #2
MOVLT r0, r14
SUBS r1, r1, #1
; xcorr[i] = sum
STR r14, [r2], #4
BLE celt_pitch_xcorr_edsp_done
celt_pitch_xcorr_edsp_process1u_done
; if (max_pitch < 4) goto celt_pitch_xcorr_edsp_process2
SUBS r1, r1, #4
BLT celt_pitch_xcorr_edsp_process2
celt_pitch_xcorr_edsp_process4
; xcorr_kernel_edsp parameters:
; r3 = len, r4 = _x, r5 = _y, r6...r9 = sum[4] = {0, 0, 0, 0}
MOV r6, #0
MOV r7, #0
MOV r8, #0
MOV r9, #0
BL xcorr_kernel_edsp_start ; xcorr_kernel_edsp(_x, _y+i, xcorr+i, len)
; maxcorr = max(maxcorr, sum0, sum1, sum2, sum3)
CMP r0, r6
; _y+=4
ADD r5, r5, #8
MOVLT r0, r6
CMP r0, r7
MOVLT r0, r7
CMP r0, r8
MOVLT r0, r8
CMP r0, r9
MOVLT r0, r9
STMIA r2!, {r6-r9}
SUBS r1, r1, #4
BGE celt_pitch_xcorr_edsp_process4
celt_pitch_xcorr_edsp_process2
ADDS r1, r1, #2
BLT celt_pitch_xcorr_edsp_process1a
SUBS r12, r3, #4
; {r10, r11} = {sum0, sum1} = {0, 0}
MOV r10, #0
MOV r11, #0
LDR r8, [r5], #4
BLE celt_pitch_xcorr_edsp_process2_loop_done
LDR r6, [r4], #4
LDR r9, [r5], #4
celt_pitch_xcorr_edsp_process2_loop4
SMLABB r10, r6, r8, r10 ; sum0 = MAC16_16(sum0, x_0, y_0)
LDR r7, [r4], #4
SMLABT r11, r6, r8, r11 ; sum1 = MAC16_16(sum1, x_0, y_1)
SUBS r12, r12, #4 ; j-=4
SMLATT r10, r6, r8, r10 ; sum0 = MAC16_16(sum0, x_1, y_1)
LDR r8, [r5], #4
SMLATB r11, r6, r9, r11 ; sum1 = MAC16_16(sum1, x_1, y_2)
LDRGT r6, [r4], #4
SMLABB r10, r7, r9, r10 ; sum0 = MAC16_16(sum0, x_2, y_2)
SMLABT r11, r7, r9, r11 ; sum1 = MAC16_16(sum1, x_2, y_3)
SMLATT r10, r7, r9, r10 ; sum0 = MAC16_16(sum0, x_3, y_3)
LDRGT r9, [r5], #4
SMLATB r11, r7, r8, r11 ; sum1 = MAC16_16(sum1, x_3, y_4)
BGT celt_pitch_xcorr_edsp_process2_loop4
celt_pitch_xcorr_edsp_process2_loop_done
ADDS r12, r12, #2
BLE celt_pitch_xcorr_edsp_process2_1
LDR r6, [r4], #4
; Stall
SMLABB r10, r6, r8, r10 ; sum0 = MAC16_16(sum0, x_0, y_0)
LDR r9, [r5], #4
SMLABT r11, r6, r8, r11 ; sum1 = MAC16_16(sum1, x_0, y_1)
SUB r12, r12, #2
SMLATT r10, r6, r8, r10 ; sum0 = MAC16_16(sum0, x_1, y_1)
MOV r8, r9
SMLATB r11, r6, r9, r11 ; sum1 = MAC16_16(sum1, x_1, y_2)
celt_pitch_xcorr_edsp_process2_1
LDRH r6, [r4], #2
ADDS r12, r12, #1
; Stall
SMLABB r10, r6, r8, r10 ; sum0 = MAC16_16(sum0, x_0, y_0)
LDRHGT r7, [r4], #2
SMLABT r11, r6, r8, r11 ; sum1 = MAC16_16(sum1, x_0, y_1)
BLE celt_pitch_xcorr_edsp_process2_done
LDRH r9, [r5], #2
SMLABT r10, r7, r8, r10 ; sum0 = MAC16_16(sum0, x_0, y_1)
SMLABB r11, r7, r9, r11 ; sum1 = MAC16_16(sum1, x_0, y_2)
celt_pitch_xcorr_edsp_process2_done
; Restore _x
SUB r4, r4, r3, LSL #1
; Restore and advance _y
SUB r5, r5, r3, LSL #1
; maxcorr = max(maxcorr, sum0)
CMP r0, r10
ADD r5, r5, #2
MOVLT r0, r10
SUB r1, r1, #2
; maxcorr = max(maxcorr, sum1)
CMP r0, r11
; xcorr[i] = sum
STR r10, [r2], #4
MOVLT r0, r11
STR r11, [r2], #4
celt_pitch_xcorr_edsp_process1a
ADDS r1, r1, #1
BLT celt_pitch_xcorr_edsp_done
SUBS r12, r3, #4
; r14 = sum = 0
MOV r14, #0
BLT celt_pitch_xcorr_edsp_process1a_loop_done
LDR r6, [r4], #4
LDR r8, [r5], #4
LDR r7, [r4], #4
LDR r9, [r5], #4
celt_pitch_xcorr_edsp_process1a_loop4
SMLABB r14, r6, r8, r14 ; sum = MAC16_16(sum, x_0, y_0)
SUBS r12, r12, #4 ; j-=4
SMLATT r14, r6, r8, r14 ; sum = MAC16_16(sum, x_1, y_1)
LDRGE r6, [r4], #4
SMLABB r14, r7, r9, r14 ; sum = MAC16_16(sum, x_2, y_2)
LDRGE r8, [r5], #4
SMLATT r14, r7, r9, r14 ; sum = MAC16_16(sum, x_3, y_3)
LDRGE r7, [r4], #4
LDRGE r9, [r5], #4
BGE celt_pitch_xcorr_edsp_process1a_loop4
celt_pitch_xcorr_edsp_process1a_loop_done
ADDS r12, r12, #2
LDRGE r6, [r4], #4
LDRGE r8, [r5], #4
; Stall
SMLABBGE r14, r6, r8, r14 ; sum = MAC16_16(sum, x_0, y_0)
SUBGE r12, r12, #2
SMLATTGE r14, r6, r8, r14 ; sum = MAC16_16(sum, x_1, y_1)
ADDS r12, r12, #1
LDRHGE r6, [r4], #2
LDRHGE r8, [r5], #2
; Stall
SMLABBGE r14, r6, r8, r14 ; sum = MAC16_16(sum, *x, *y)
; maxcorr = max(maxcorr, sum)
CMP r0, r14
; xcorr[i] = sum
STR r14, [r2], #4
MOVLT r0, r14
celt_pitch_xcorr_edsp_done
LDMFD sp!, {r4-r11, pc}
ENDP
ENDIF
END