1b05ea8ffe
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12732 a1c6a512-1295-4272-9138-f99709370657
204 lines
9.7 KiB
ArmAsm
204 lines
9.7 KiB
ArmAsm
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2006-2007 Thom Johansen
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*
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* All files in this archive are subject to the GNU General Public License.
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* See the file COPYING in the source tree root for full license agreement.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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/****************************************************************************
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* void apply_crossfeed(int count, int32_t* src[])
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*/
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.section .text
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.global apply_crossfeed
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apply_crossfeed:
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@ unfortunately, we ended up in a bit of a register squeeze here, and need
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@ to keep the count on the stack :/
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stmdb sp!, { r4-r11, lr } @ stack modified regs
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ldmia r1, { r2-r3 } @ r2 = src[0], r3 = src[1]
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ldr r1, =crossfeed_data
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ldmia r1!, { r4-r11 } @ load direct gain and filter data
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add r12, r1, #13*4*2 @ calculate end of delay
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stmdb sp!, { r0, r12 } @ stack count and end of delay adr
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ldr r0, [r1, #13*4*2] @ fetch current delay line address
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/* Register usage in loop:
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* r0 = &delay[index][0], r1 = accumulator high, r2 = src[0], r3 = src[1],
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* r4 = direct gain, r5-r7 = b0, b1, a1 (filter coefs),
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* r8-r11 = filter history, r12 = temp, r14 = accumulator low
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*/
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.cfloop:
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smull r14, r1, r6, r8 @ acc = b1*dr[n - 1]
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smlal r14, r1, r7, r9 @ acc += a1*y_l[n - 1]
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ldr r8, [r0, #4] @ r8 = dr[n]
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smlal r14, r1, r5, r8 @ acc += b0*dr[n]
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mov r9, r1, lsl #1 @ fix format for filter history
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ldr r12, [r2] @ load left input
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smlal r14, r1, r4, r12 @ acc += gain*x_l[n]
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mov r1, r1, lsl #1 @ fix format
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str r1, [r2], #4 @ save result
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smull r14, r1, r6, r10 @ acc = b1*dl[n - 1]
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smlal r14, r1, r7, r11 @ acc += a1*y_r[n - 1]
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ldr r10, [r0] @ r10 = dl[n]
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str r12, [r0], #4 @ save left input to delay line
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smlal r14, r1, r5, r10 @ acc += b0*dl[n]
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mov r11, r1, lsl #1 @ fix format for filter history
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ldr r12, [r3] @ load right input
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smlal r14, r1, r4, r12 @ acc += gain*x_r[n]
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str r12, [r0], #4 @ save right input to delay line
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mov r1, r1, lsl #1 @ fix format
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str r1, [r3], #4 @ save result
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ldr r12, [sp, #4] @ fetch delay line end addr from stack
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cmp r0, r12 @ need to wrap to start of delay?
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subeq r0, r0, #13*4*2 @ wrap back delay line ptr to start
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ldr r1, [sp] @ fetch count from stack
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subs r1, r1, #1 @ are we finished?
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strne r1, [sp] @ nope, save count back to stack
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bne .cfloop
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@ save data back to struct
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ldr r12, =crossfeed_data + 4*4
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stmia r12, { r8-r11 } @ save filter history
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str r0, [r12, #30*4] @ save delay line index
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add sp, sp, #8 @ remove temp variables from stack
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ldmia sp!, { r4-r11, pc }
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.cfend:
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.size apply_crossfeed,.cfend-apply_crossfeed
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/****************************************************************************
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* int dsp_downsample(int count, struct dsp_data *data,
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* in32_t *src[], int32_t *dst[])
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*/
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.section .text
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.global dsp_downsample
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dsp_downsample:
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stmdb sp!, { r4-r11, lr } @ stack modified regs
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ldmib r1, { r5-r6 } @ r5 = num_channels,r6 = resample_data.delta
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sub r5, r5, #1 @ pre-decrement num_channels for use
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add r4, r1, #12 @ r4 = &resample_data.phase
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mov r12, #0xff
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orr r12, r12, #0xff00 @ r12 = 0xffff
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.dschannel_loop:
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ldr r1, [r4] @ r1 = resample_data.phase
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ldr r7, [r2, r5, lsl #2] @ r7 = s = src[ch - 1]
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ldr r8, [r3, r5, lsl #2] @ r8 = d = dst[ch - 1]
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add r9, r4, #4 @ r9 = &last_sample[0]
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ldr r10, [r9, r5, lsl #2] @ r10 = last_sample[ch - 1]
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sub r11, r0, #1
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ldr r14, [r7, r11, lsl #2] @ load last sample in s[] ...
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str r14, [r9, r5, lsl #2] @ and write as next frame's last_sample
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movs r9, r1, lsr #16 @ r9 = pos = phase >> 16
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ldreq r11, [r7] @ if pos = 0, load src[0] and jump into loop
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beq .dsuse_last_start
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cmp r9, r0 @ if pos >= count, we're already done
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bge .dsloop_skip
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@ Register usage in loop:
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@ r0 = count, r1 = phase, r4 = &resample_data.phase, r5 = cur_channel,
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@ r6 = delta, r7 = s, r8 = d, r9 = pos, r10 = s[pos - 1], r11 = s[pos]
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.dsloop:
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add r9, r7, r9, lsl #2 @ r9 = &s[pos]
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ldmda r9, { r10, r11 } @ r10 = s[pos - 1], r11 = s[pos]
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.dsuse_last_start:
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sub r11, r11, r10 @ r11 = diff = s[pos] - s[pos - 1]
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@ keep frac in lower bits to take advantage of multiplier early termination
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and r9, r1, r12 @ frac = phase & 0xffff
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smull r9, r14, r11, r9
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add r10, r10, r14, lsl #16
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add r10, r10, r9, lsr #16 @ r10 = out = s[pos - 1] + frac*diff
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str r10, [r8], #4 @ *d++ = out
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add r1, r1, r6 @ phase += delta
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mov r9, r1, lsr #16 @ pos = phase >> 16
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cmp r9, r0 @ pos < count?
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blt .dsloop @ yup, do more samples
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.dsloop_skip:
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subs r5, r5, #1
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bpl .dschannel_loop @ if (--ch) >= 0, do another channel
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sub r1, r1, r0, lsl #16 @ wrap phase back to start
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str r1, [r4] @ store back
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ldr r1, [r3] @ r1 = &dst[0]
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sub r8, r8, r1 @ dst - &dst[0]
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mov r0, r8, lsr #2 @ convert bytes->samples
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ldmia sp!, { r4-r11, pc } @ ... and we're out
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.dsend:
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.size dsp_downsample,.dsend-dsp_downsample
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/****************************************************************************
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* int dsp_upsample(int count, struct dsp_data *dsp,
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* in32_t *src[], int32_t *dst[])
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*/
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.section .text
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.global dsp_upsample
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dsp_upsample:
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stmdb sp!, { r4-r11, lr } @ stack modified regs
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ldmib r1, { r5-r6 } @ r5 = num_channels,r6 = resample_data.delta
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sub r5, r5, #1 @ pre-decrement num_channels for use
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add r4, r1, #12 @ r4 = &resample_data.phase
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stmdb sp!, { r0, r4 } @ stack count and &resample_data.phase
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.uschannel_loop:
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ldr r12, [r4] @ r12 = resample_data.phase
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mov r1, r12, ror #16 @ swap halfword positions, we'll use carry
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@ to detect pos increments
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ldr r7, [r2, r5, lsl #2] @ r7 = s = src[ch - 1]
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ldr r8, [r3, r5, lsl #2] @ r8 = d = dst[ch - 1]
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add r9, r4, #4 @ r9 = &last_sample[0]
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ldr r10, [r9, r5, lsl #2] @ r10 = last_sample[ch - 1]
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sub r11, r0, #1
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ldr r14, [r7, r11, lsl #2] @ load last sample in s[] ...
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str r14, [r9, r5, lsl #2] @ and write as next frame's last_sample
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add r9, r7, r0, lsl #2 @ r9 = src_end = &src[count]
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movs r14, r12, lsr #16 @ pos = resample_data.phase >> 16
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beq .usstart_0 @ pos = 0
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cmp r14, r0 @ if pos >= count, we're already done
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bge .usloop_skip
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add r7, r7, r14, lsl #2 @ r7 = &s[pos]
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ldr r10, [r7, #-4] @ r11 = s[pos - 1]
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b .usstart_0
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@ Register usage in loop:
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@ r0 = count, r1 = phase, r4 = &resample_data.phase, r5 = cur_channel,
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@ r6 = delta, r7 = s, r8 = d, r9 = src_end, r10 = s[pos - 1], r11 = s[pos]
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.usloop_1:
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mov r10, r11 @ r10 = previous sample
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.usstart_0:
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ldr r11, [r7], #4 @ r11 = next sample
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sub r0, r11, r10 @ r0 = s[pos] - s[pos - 1]
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.usloop_0:
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mov r4, r1, lsr #16 @ r4 = frac = phase >> 16
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smull r12, r14, r4, r0
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add r14, r10, r14, lsl #16
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add r14, r14, r12, lsr #16 @ r14 = out = s[pos - 1] + frac*diff
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str r14, [r8], #4 @ *d++ = out
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adds r1, r1, r6, lsl #16 @ phase += delta << 16
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bcc .usloop_0 @ if carry is set, pos is incremented
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cmp r7, r9 @ if s < src_end, do another sample
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blo .usloop_1
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.usloop_skip:
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subs r5, r5, #1
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ldmia sp, { r0, r4 } @ reload count and &resample_data.phase
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bpl .uschannel_loop @ if (--ch) >= 0, do another channel
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mov r1, r1, ror #16 @ wrap phase back to start of next frame
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str r1, [r4] @ store back
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ldr r1, [r3] @ r1 = &dst[0]
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sub r8, r8, r1 @ dst - &dst[0]
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mov r0, r8, lsr #2 @ convert bytes->samples
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add sp, sp, #8 @ adjust stack for temp variables
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ldmia sp!, { r4-r11, pc } @ ... and we're out
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.usend:
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.size dsp_upsample,.usend-dsp_upsample
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