FreeCalypso > hg > gsm-codec-lib
annotate libtwamr/sqrt_l.c @ 365:2a265be82195
libtwamr: integrate g_adapt.c
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Mon, 06 May 2024 03:01:15 +0000 |
parents | 8dfb7cbe6b59 |
children |
rev | line source |
---|---|
308
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
1 /* |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
2 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
3 * |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
4 * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
5 * R99 Version 3.3.0 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
6 * REL-4 Version 4.1.0 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
7 * |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
8 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
9 * |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
10 * File : sqrt_l.c |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
11 * Purpose : Computes sqrt(L_x), where L_x is positive. |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
12 * : If L_var is negative or zero, the result is 0 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
13 * Description : |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
14 * The function sqrt(L_x) is approximated by a table and linear |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
15 * interpolation. The square root is computed using the |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
16 * following steps: |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
17 * 1- Normalization of L_x. |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
18 * 2- If exponent is even then shift right once. |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
19 * 3- exponent = exponent/2 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
20 * 4- i = bit25-b31 of L_x; 16<=i<=63 because of normalization. |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
21 * 5- a = bit10-b24 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
22 * 6- i -=16 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
23 * 7- L_y = table[i]<<16 - (table[i] - table[i+1]) * a * 2 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
24 * 8- return L_y and exponent so caller can do denormalization |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
25 * |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
26 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
27 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
28 /* |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
29 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
30 * MODULE INCLUDE FILE AND VERSION ID |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
31 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
32 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
33 #include "namespace.h" |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
34 #include "sqrt_l.h" |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
35 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
36 /* |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
37 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
38 * INCLUDE FILES |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
39 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
40 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
41 #include "typedef.h" |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
42 #include "basic_op.h" |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
43 #include "no_count.h" |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
44 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
45 /* |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
46 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
47 * LOCAL VARIABLES AND TABLES |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
48 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
49 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
50 #include "sqrt_l.tab" /* Table for sqrt_l_exp() */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
51 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
52 /* |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
53 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
54 * PUBLIC PROGRAM CODE |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
55 ******************************************************************************** |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
56 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
57 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
58 Word32 sqrt_l_exp (/* o : output value, Q31 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
59 Word32 L_x, /* i : input value, Q31 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
60 Word16 *exp /* o : right shift to be applied to result, Q1 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
61 ) |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
62 { |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
63 /* |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
64 y = sqrt(x) |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
65 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
66 x = f * 2^-e, 0.5 <= f < 1 (normalization) |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
67 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
68 y = sqrt(f) * 2^(-e/2) |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
69 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
70 a) e = 2k --> y = sqrt(f) * 2^-k (k = e div 2, |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
71 0.707 <= sqrt(f) < 1) |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
72 b) e = 2k+1 --> y = sqrt(f/2) * 2^-k (k = e div 2, |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
73 0.5 <= sqrt(f/2) < 0.707) |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
74 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
75 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
76 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
77 Word16 e, i, a, tmp; |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
78 Word32 L_y; |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
79 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
80 test (); |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
81 if (L_x <= (Word32) 0) |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
82 { |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
83 *exp = 0; move16 (); |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
84 return (Word32) 0; |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
85 } |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
86 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
87 e = norm_l (L_x) & 0xFFFE; logic16 (); /* get next lower EVEN norm. exp */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
88 L_x = L_shl (L_x, e); /* L_x is normalized to [0.25..1) */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
89 *exp = e; move16 (); /* return 2*exponent (or Q1) */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
90 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
91 L_x = L_shr (L_x, 9); |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
92 i = extract_h (L_x); /* Extract b25-b31, 16 <= i <= 63 because |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
93 of normalization */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
94 L_x = L_shr (L_x, 1); |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
95 a = extract_l (L_x); /* Extract b10-b24 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
96 a = a & (Word16) 0x7fff; logic16 (); |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
97 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
98 i = sub (i, 16); /* 0 <= i <= 47 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
99 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
100 L_y = L_deposit_h (table[i]); /* table[i] << 16 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
101 tmp = sub (table[i], table[i + 1]); /* table[i] - table[i+1]) */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
102 L_y = L_msu (L_y, tmp, a); /* L_y -= tmp*a*2 */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
103 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
104 /* L_y = L_shr (L_y, *exp); */ /* denormalization done by caller */ |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
105 |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
106 return (L_y); |
8dfb7cbe6b59
libtwamr: integrated up to bgnscd.c
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
107 } |