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