ARM assembler for resampling. Should provide some gains, though not huge ones.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12732 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Thom Johansen
parent
1b3fc39a65
commit
1b05ea8ffe
2 changed files with 129 additions and 6 deletions
128
apps/dsp_arm.S
128
apps/dsp_arm.S
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@ -17,14 +17,14 @@
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*
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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 both the count and the delay line index on the stack :/
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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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@ -77,4 +77,128 @@ apply_crossfeed:
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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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@ -27,13 +27,12 @@
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#if defined(CPU_COLDFIRE) || defined(CPU_ARM)
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#define DSP_HAVE_ASM_CROSSFEED
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void apply_crossfeed(int count, int32_t *buf[]);
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#endif /* defined(CPU_COLDFIRE) || defined(CPU_ARM) */
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#if defined (CPU_COLDFIRE)
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#define DSP_HAVE_ASM_RESAMPLING
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int dsp_downsample(int count, struct dsp_data *data, int32_t *src[], int32_t *dst[]);
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int dsp_upsample(int count, struct dsp_data *data, int32_t *src[], int32_t *dst[]);
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#endif /* defined(CPU_COLDFIRE) || defined(CPU_ARM) */
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#if defined (CPU_COLDFIRE)
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#define DSP_HAVE_ASM_SOUND_CHAN_MONO
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void channels_process_sound_chan_mono(int count, int32_t *buf[]);
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#define DSP_HAVE_ASM_SOUND_CHAN_CUSTOM
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