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-rw-r--r--apps/dsp_arm.S91
1 files changed, 46 insertions, 45 deletions
diff --git a/apps/dsp_arm.S b/apps/dsp_arm.S
index 1abfd34983..27669203f1 100644
--- a/apps/dsp_arm.S
+++ b/apps/dsp_arm.S
@@ -7,7 +7,7 @@
7 * \/ \/ \/ \/ \/ 7 * \/ \/ \/ \/ \/
8 * $Id$ 8 * $Id$
9 * 9 *
10 * Copyright (C) 2006 Thom Johansen 10 * Copyright (C) 2006-2007 Thom Johansen
11 * 11 *
12 * All files in this archive are subject to the GNU General Public License. 12 * All files in this archive are subject to the GNU General Public License.
13 * See the file COPYING in the source tree root for full license agreement. 13 * See the file COPYING in the source tree root for full license agreement.
@@ -17,63 +17,64 @@
17 * 17 *
18 ****************************************************************************/ 18 ****************************************************************************/
19 19
20/*
21 * void apply_crossfeed(int count, int32_t* src[])
22 */
20 .section .text 23 .section .text
21 .global apply_crossfeed 24 .global apply_crossfeed
22apply_crossfeed: 25apply_crossfeed:
23 @ unfortunately, we ended up in a bit of a register squeeze here, and need 26 @ unfortunately, we ended up in a bit of a register squeeze here, and need
24 @ to keep both the count and the delay line index on the stack :/ 27 @ to keep both the count and the delay line index on the stack :/
25 stmdb sp!, { r4-r11, lr } @ stack modified regs 28 stmdb sp!, { r4-r11, lr } @ stack modified regs
26 ldmia r0, { r2-r3 } @ r2 = src[0], r3 = src[1] 29 ldmia r1, { r2-r3 } @ r2 = src[0], r3 = src[1]
27 30
28 ldr r0, =crossfeed_data 31 ldr r1, =crossfeed_data
29 ldmia r0!, { r4-r11 } @ load direct gain and filter data 32 ldmia r1!, { r4-r11 } @ load direct gain and filter data
30 ldr r12, [r0, #13*4*2] @ fetch delay line index 33 add r12, r1, #13*4*2 @ calculate end of delay
31 add r0, r0, r12, lsl #3 @ r0 = &delay[index][0] 34 stmdb sp!, { r0, r12 } @ stack count and end of delay adr
32 stmdb sp!, { r1, r12 } @ stack count and delay line index 35 ldr r0, [r1, #13*4*2] @ fetch current delay line address
36
33 /* Register usage in loop: 37 /* Register usage in loop:
34 * r0 = &delay[index][0], r1 = accumulator high, r2 = src[0], r3 = src[1], 38 * r0 = &delay[index][0], r1 = accumulator high, r2 = src[0], r3 = src[1],
35 * r4 = direct gain, r5-r7 = b0, b1, a1 (filter coefs), 39 * r4 = direct gain, r5-r7 = b0, b1, a1 (filter coefs),
36 * r8-r11 = filter history, r12 = temp, r14 = accumulator low 40 * r8-r11 = filter history, r12 = temp, r14 = accumulator low
37 */ 41 */
38.cfloop: 42.cfloop:
39 smull r14, r1, r6, r8 @ acc = b1*dr[n - 1] 43 smull r14, r1, r6, r8 @ acc = b1*dr[n - 1]
40 smlal r14, r1, r7, r9 @ acc += a1*y_l[n - 1] 44 smlal r14, r1, r7, r9 @ acc += a1*y_l[n - 1]
41 ldr r8, [r0, #4] @ r8 = dr[n] 45 ldr r8, [r0, #4] @ r8 = dr[n]
42 smlal r14, r1, r5, r8 @ acc += b0*dr[n] 46 smlal r14, r1, r5, r8 @ acc += b0*dr[n]
43 mov r9, r1, lsl #1 @ fix format for filter history 47 mov r9, r1, lsl #1 @ fix format for filter history
44 ldr r12, [r2] @ load left input 48 ldr r12, [r2] @ load left input
45 smlal r14, r1, r4, r12 @ acc += gain*x_l[n] 49 smlal r14, r1, r4, r12 @ acc += gain*x_l[n]
46 mov r1, r1, lsl #1 @ fix format 50 mov r1, r1, lsl #1 @ fix format
47 str r1, [r2], #4 @ save result 51 str r1, [r2], #4 @ save result
48
49 smull r14, r1, r6, r10 @ acc = b1*dl[n - 1]
50 smlal r14, r1, r7, r11 @ acc += a1*y_r[n - 1]
51 ldr r10, [r0] @ r10 = dl[n]
52 str r12, [r0], #4 @ save left input to delay line
53 smlal r14, r1, r5, r10 @ acc += b0*dl[n]
54 mov r11, r1, lsl #1 @ fix format for filter history
55 ldr r12, [r3] @ load right input
56 smlal r14, r1, r4, r12 @ acc += gain*x_r[n]
57 str r12, [r0], #4 @ save right input to delay line
58 mov r1, r1, lsl #1 @ fix format
59 str r1, [r3], #4 @ save result
60 52
61 ldr r12, [sp, #4] @ fetch delay line index from stack 53 smull r14, r1, r6, r10 @ acc = b1*dl[n - 1]
62 add r12, r12, #1 @ increment index 54 smlal r14, r1, r7, r11 @ acc += a1*y_r[n - 1]
63 cmp r12, #13 @ do we need to wrap to start of delay? 55 ldr r10, [r0] @ r10 = dl[n]
64 moveq r12, #0 @ yes, wrap index to 0 56 str r12, [r0], #4 @ save left input to delay line
65 subeq r0, r0, #13*4*2 @ also wrap back delay line ptr to start 57 smlal r14, r1, r5, r10 @ acc += b0*dl[n]
66 str r12, [sp, #4] @ stack delay line index again 58 mov r11, r1, lsl #1 @ fix format for filter history
67 59 ldr r12, [r3] @ load right input
68 ldr r1, [sp] @ fetch count from stack 60 smlal r14, r1, r4, r12 @ acc += gain*x_r[n]
69 subs r1, r1, #1 @ are we finished? 61 str r12, [r0], #4 @ save right input to delay line
70 strne r1, [sp] @ nope, save count back to stack 62 mov r1, r1, lsl #1 @ fix format
71 bne .cfloop 63 str r1, [r3], #4 @ save result
64
65 ldr r12, [sp, #4] @ fetch delay line end addr from stack
66 cmp r0, r12 @ need to wrap to start of delay?
67 subeq r0, r0, #13*4*2 @ wrap back delay line ptr to start
68
69 ldr r1, [sp] @ fetch count from stack
70 subs r1, r1, #1 @ are we finished?
71 strne r1, [sp] @ nope, save count back to stack
72 bne .cfloop
72 73
73 @ save data back to struct 74 @ save data back to struct
74 ldr r0, =crossfeed_data + 4*4 75 ldr r12, =crossfeed_data + 4*4
75 stmia r0, { r8-r11 } @ save filter history 76 stmia r12, { r8-r11 } @ save filter history
76 str r12, [r0, #30*4] @ save delay line index 77 str r0, [r12, #30*4] @ save delay line index
77 add sp, sp, #8 @ remove temp variables from stack 78 add sp, sp, #8 @ remove temp variables from stack
78 ldmia sp!, { r4-r11, pc } 79 ldmia sp!, { r4-r11, pc }
79 80
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