ddnet/src/engine/external/wavpack/arm.S

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ArmAsm
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2007-05-22 15:03:32 +00:00
////////////////////////////////////////////////////////////////////////////
// **** WAVPACK **** //
// Hybrid Lossless Wavefile Compressor //
// Copyright (c) 1998 - 2006 Conifer Software. //
// All Rights Reserved. //
// Distributed under the BSD Software License (see license.txt) //
////////////////////////////////////////////////////////////////////////////
/* This is an assembly optimized version of the following WavPack function:
*
* void decorr_stereo_pass_cont (struct decorr_pass *dpp,
* long *buffer, long sample_count);
*
* It performs a single pass of stereo decorrelation on the provided buffer.
* Note that this version of the function requires that the 8 previous stereo
* samples are visible and correct. In other words, it ignores the "samples_*"
* fields in the decorr_pass structure and gets the history data directly
* from the buffer. It does, however, return the appropriate history samples
* to the decorr_pass structure before returning.
*
* This is written to work on a ARM7TDMI processor. This version only uses the
* 32-bit multiply-accumulate instruction and so will overflow with 24-bit
* WavPack files.
*/
.text
.align
.global decorr_stereo_pass_cont_arm
/*
* on entry:
*
* r0 = struct decorr_pass *dpp
* r1 = long *buffer
* r2 = long sample_count
*/
decorr_stereo_pass_cont_arm:
stmfd sp!, {r4 - r8, r10, r11, lr}
mov r5, r0 @ r5 = dpp
mov r11, #512 @ r11 = 512 for rounding
ldrsh r6, [r0, #2] @ r6 = dpp->delta
ldrsh r4, [r0, #4] @ r4 = dpp->weight_A
ldrsh r0, [r0, #6] @ r0 = dpp->weight_B
cmp r2, #0 @ exit if no samples to process
beq common_exit
add r7, r1, r2, asl #3 @ r7 = buffer ending position
ldrsh r2, [r5, #0] @ r2 = dpp->term
cmp r2, #0
bmi minus_term
ldr lr, [r1, #-16] @ load 2 sample history from buffer
ldr r10, [r1, #-12] @ for terms 2, 17, and 18
ldr r8, [r1, #-8]
ldr r3, [r1, #-4]
cmp r2, #17
beq term_17_loop
cmp r2, #18
beq term_18_loop
cmp r2, #2
beq term_2_loop
b term_default_loop @ else handle default (1-8, except 2)
minus_term:
mov r10, #1024 @ r10 = -1024 for weight clipping
rsb r10, r10, #0 @ (only used for negative terms)
cmn r2, #1
beq term_minus_1
cmn r2, #2
beq term_minus_2
cmn r2, #3
beq term_minus_3
b common_exit
/*
******************************************************************************
* Loop to handle term = 17 condition
*
* r0 = dpp->weight_B r8 = previous left sample
* r1 = bptr r9 =
* r2 = current sample r10 = second previous left sample
* r3 = previous right sample r11 = 512 (for rounding)
* r4 = dpp->weight_A ip = current decorrelation value
* r5 = dpp sp =
* r6 = dpp->delta lr = second previous right sample
* r7 = eptr pc =
*******************************************************************************
*/
term_17_loop:
rsbs ip, lr, r8, asl #1 @ decorr value = (2 * prev) - 2nd prev
mov lr, r8 @ previous becomes 2nd previous
ldr r2, [r1], #4 @ get sample & update pointer
mla r8, ip, r4, r11 @ mult decorr value by weight, round,
add r8, r2, r8, asr #10 @ shift, and add to new sample
strne r8, [r1, #-4] @ if change possible, store sample back
cmpne r2, #0
beq .L325
teq ip, r2 @ update weight based on signs
submi r4, r4, r6
addpl r4, r4, r6
.L325: rsbs ip, r10, r3, asl #1 @ do same thing for right channel
mov r10, r3
ldr r2, [r1], #4
mla r3, ip, r0, r11
add r3, r2, r3, asr #10
strne r3, [r1, #-4]
cmpne r2, #0
beq .L329
teq ip, r2
submi r0, r0, r6
addpl r0, r0, r6
.L329: cmp r7, r1 @ loop back if more samples to do
bhi term_17_loop
b store_1718 @ common exit for terms 17 & 18
/*
******************************************************************************
* Loop to handle term = 18 condition
*
* r0 = dpp->weight_B r8 = previous left sample
* r1 = bptr r9 =
* r2 = current sample r10 = second previous left sample
* r3 = previous right sample r11 = 512 (for rounding)
* r4 = dpp->weight_A ip = decorrelation value
* r5 = dpp sp =
* r6 = dpp->delta lr = second previous right sample
* r7 = eptr pc =
*******************************************************************************
*/
term_18_loop:
sub ip, r8, lr @ decorr value =
mov lr, r8 @ ((3 * prev) - 2nd prev) >> 1
adds ip, r8, ip, asr #1
ldr r2, [r1], #4 @ get sample & update pointer
mla r8, ip, r4, r11 @ mult decorr value by weight, round,
add r8, r2, r8, asr #10 @ shift, and add to new sample
strne r8, [r1, #-4] @ if change possible, store sample back
cmpne r2, #0
beq .L337
teq ip, r2 @ update weight based on signs
submi r4, r4, r6
addpl r4, r4, r6
.L337: sub ip, r3, r10 @ do same thing for right channel
mov r10, r3
adds ip, r3, ip, asr #1
ldr r2, [r1], #4
mla r3, ip, r0, r11
add r3, r2, r3, asr #10
strne r3, [r1, #-4]
cmpne r2, #0
beq .L341
teq ip, r2
submi r0, r0, r6
addpl r0, r0, r6
.L341: cmp r7, r1 @ loop back if more samples to do
bhi term_18_loop
/* common exit for terms 17 & 18 */
store_1718:
str r3, [r5, #40] @ store sample history into struct
str r8, [r5, #8]
str r10, [r5, #44]
str lr, [r5, #12]
b common_exit @ and return
/*
******************************************************************************
* Loop to handle term = 2 condition
* (note that this case can be handled by the default term handler (1-8), but
* this special case is faster because it doesn't have to read memory twice)
*
* r0 = dpp->weight_B r8 = previous left sample
* r1 = bptr r9 =
* r2 = current sample r10 = second previous left sample
* r3 = previous right sample r11 = 512 (for rounding)
* r4 = dpp->weight_A ip = decorrelation value
* r5 = dpp sp =
* r6 = dpp->delta lr = second previous right sample
* r7 = eptr pc =
*******************************************************************************
*/
term_2_loop:
movs ip, lr @ get decorrelation value & test
mov lr, r8 @ previous becomes 2nd previous
ldr r2, [r1], #4 @ get sample & update pointer
mla r8, ip, r4, r11 @ mult decorr value by weight, round,
add r8, r2, r8, asr #10 @ shift, and add to new sample
strne r8, [r1, #-4] @ if change possible, store sample back
cmpne r2, #0
beq .L225
teq ip, r2 @ update weight based on signs
submi r4, r4, r6
addpl r4, r4, r6
.L225: movs ip, r10 @ do same thing for right channel
mov r10, r3
ldr r2, [r1], #4
mla r3, ip, r0, r11
add r3, r2, r3, asr #10
strne r3, [r1, #-4]
cmpne r2, #0
beq .L229
teq ip, r2
submi r0, r0, r6
addpl r0, r0, r6
.L229: cmp r7, r1 @ loop back if more samples to do
bhi term_2_loop
b default_term_exit @ this exit updates all dpp->samples
/*
******************************************************************************
* Loop to handle default term condition
*
* r0 = dpp->weight_B r8 = result accumulator
* r1 = bptr r9 =
* r2 = dpp->term r10 =
* r3 = decorrelation value r11 = 512 (for rounding)
* r4 = dpp->weight_A ip = current sample
* r5 = dpp sp =
* r6 = dpp->delta lr =
* r7 = eptr pc =
*******************************************************************************
*/
term_default_loop:
ldr ip, [r1] @ get original sample
ldr r3, [r1, -r2, asl #3] @ get decorrelation value based on term
mla r8, r3, r4, r11 @ mult decorr value by weight, round,
add r8, ip, r8, asr #10 @ shift and add to new sample
str r8, [r1], #4 @ store update sample
cmp r3, #0
cmpne ip, #0
beq .L350
teq ip, r3 @ update weight based on signs
submi r4, r4, r6
addpl r4, r4, r6
.L350: ldr ip, [r1] @ do the same thing for right channel
ldr r3, [r1, -r2, asl #3]
mla r8, r3, r0, r11
add r8, ip, r8, asr #10
str r8, [r1], #4
cmp r3, #0
cmpne ip, #0
beq .L354
teq ip, r3
submi r0, r0, r6
addpl r0, r0, r6
.L354: cmp r7, r1 @ loop back if more samples to do
bhi term_default_loop
/*
* This exit is used by terms 1-8 to store the previous 8 samples into the decorr
* structure (even if they are not all used for the given term)
*/
default_term_exit:
ldrsh r3, [r5, #0]
sub ip, r3, #1
mov lr, #7
.L358: and r3, ip, #7
add r3, r5, r3, asl #2
ldr r2, [r1, #-4]
str r2, [r3, #40]
ldr r2, [r1, #-8]!
str r2, [r3, #8]
sub ip, ip, #1
sub lr, lr, #1
cmn lr, #1
bne .L358
b common_exit
/*
******************************************************************************
* Loop to handle term = -1 condition
*
* r0 = dpp->weight_B r8 =
* r1 = bptr r9 =
* r2 = intermediate result r10 = -1024 (for clipping)
* r3 = previous right sample r11 = 512 (for rounding)
* r4 = dpp->weight_A ip = current sample
* r5 = dpp sp =
* r6 = dpp->delta lr = updated left sample
* r7 = eptr pc =
*******************************************************************************
*/
term_minus_1:
ldr r3, [r1, #-4]
term_minus_1_loop:
ldr ip, [r1] @ for left channel the decorrelation value
mla r2, r3, r4, r11 @ is the previous right sample (in r3)
add lr, ip, r2, asr #10
str lr, [r1], #8
cmp r3, #0
cmpne ip, #0
beq .L361
teq ip, r3 @ update weight based on signs
submi r4, r4, r6
addpl r4, r4, r6
cmp r4, #1024
movgt r4, #1024
cmp r4, r10
movlt r4, r10
.L361: ldr r2, [r1, #-4] @ for right channel the decorrelation value
mla r3, lr, r0, r11 @ is the just updated right sample (in lr)
add r3, r2, r3, asr #10
str r3, [r1, #-4]
cmp lr, #0
cmpne r2, #0
beq .L369
teq r2, lr
submi r0, r0, r6
addpl r0, r0, r6
cmp r0, #1024 @ then clip weight to +/-1024
movgt r0, #1024
cmp r0, r10
movlt r0, r10
.L369: cmp r7, r1 @ loop back if more samples to do
bhi term_minus_1_loop
str r3, [r5, #8] @ else store right sample and exit
b common_exit
/*
******************************************************************************
* Loop to handle term = -2 condition
* (note that the channels are processed in the reverse order here)
*
* r0 = dpp->weight_B r8 =
* r1 = bptr r9 =
* r2 = intermediate result r10 = -1024 (for clipping)
* r3 = previous left sample r11 = 512 (for rounding)
* r4 = dpp->weight_A ip = current sample
* r5 = dpp sp =
* r6 = dpp->delta lr = updated right sample
* r7 = eptr pc =
*******************************************************************************
*/
term_minus_2:
ldr r3, [r1, #-8]
term_minus_2_loop:
ldr ip, [r1, #4] @ for right channel the decorrelation value
mla r2, r3, r0, r11 @ is the previous left sample (in r3)
add lr, ip, r2, asr #10
str lr, [r1, #4]
cmp r3, #0
cmpne ip, #0
beq .L380
teq ip, r3 @ update weight based on signs
submi r0, r0, r6
addpl r0, r0, r6
cmp r0, #1024 @ then clip weight to +/-1024
movgt r0, #1024
cmp r0, r10
movlt r0, r10
.L380: ldr r2, [r1, #0] @ for left channel the decorrelation value
mla r3, lr, r4, r11 @ is the just updated left sample (in lr)
add r3, r2, r3, asr #10
str r3, [r1], #8
cmp lr, #0
cmpne r2, #0
beq .L388
teq r2, lr
submi r4, r4, r6
addpl r4, r4, r6
cmp r4, #1024
movgt r4, #1024
cmp r4, r10
movlt r4, r10
.L388: cmp r7, r1 @ loop back if more samples to do
bhi term_minus_2_loop
str r3, [r5, #40] @ else store left channel and exit
b common_exit
/*
******************************************************************************
* Loop to handle term = -3 condition
*
* r0 = dpp->weight_B r8 = previous left sample
* r1 = bptr r9 =
* r2 = current left sample r10 = -1024 (for clipping)
* r3 = previous right sample r11 = 512 (for rounding)
* r4 = dpp->weight_A ip = intermediate result
* r5 = dpp sp =
* r6 = dpp->delta lr =
* r7 = eptr pc =
*******************************************************************************
*/
term_minus_3:
ldr r3, [r1, #-4] @ load previous samples
ldr r8, [r1, #-8]
term_minus_3_loop:
ldr ip, [r1]
mla r2, r3, r4, r11
add r2, ip, r2, asr #10
str r2, [r1], #4
cmp r3, #0
cmpne ip, #0
beq .L399
teq ip, r3 @ update weight based on signs
submi r4, r4, r6
addpl r4, r4, r6
cmp r4, #1024 @ then clip weight to +/-1024
movgt r4, #1024
cmp r4, r10
movlt r4, r10
.L399: movs ip, r8 @ ip = previous left we use now
mov r8, r2 @ r8 = current left we use next time
ldr r2, [r1], #4
mla r3, ip, r0, r11
add r3, r2, r3, asr #10
strne r3, [r1, #-4]
cmpne r2, #0
beq .L407
teq ip, r2
submi r0, r0, r6
addpl r0, r0, r6
cmp r0, #1024
movgt r0, #1024
cmp r0, r10
movlt r0, r10
.L407: cmp r7, r1 @ loop back if more samples to do
bhi term_minus_3_loop
str r3, [r5, #8] @ else store previous samples & exit
str r8, [r5, #40]
/*
* Before finally exiting we must store weights back for next time
*/
common_exit:
strh r4, [r5, #4]
strh r0, [r5, #6]
ldmfd sp!, {r4 - r8, r10, r11, pc}