annotate Discovery/Src/crcmodel.c @ 747:df0d43da1614

Added pressure compensation to CO2 detection: A pressure compensation is needed if the ExplorIR shall be used under extended pressure conditions. The procedure recommended by the application note has been integrated. To keep things simple the focus of the CO2 measurement is not the precision, as it is needed for the decompression calculation, but the indication of a critical increase of CO2 in the breathing loop. That's why only a lookup table with 1000ppm steps has been implemented instead of calculating the polynom for every measurement.
author Ideenmodellierer
date Sun, 05 Mar 2023 22:06:47 +0100
parents 5f11787b4f42
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
38
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
1 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
2 /* Start of crcmodel.c */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
3 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
4 /* */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
5 /* Author : Ross Williams (ross@guest.adelaide.edu.au.). */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
6 /* Date : 3 June 1993. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
7 /* Status : Public domain. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
8 /* */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
9 /* Description : This is the implementation (.c) file for the reference */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
10 /* implementation of the Rocksoft^tm Model CRC Algorithm. For more */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
11 /* information on the Rocksoft^tm Model CRC Algorithm, see the document */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
12 /* titled "A Painless Guide to CRC Error Detection Algorithms" by Ross */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
13 /* Williams (ross@guest.adelaide.edu.au.). This document is likely to be in */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
14 /* "ftp.adelaide.edu.au/pub/rocksoft". */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
15 /* */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
16 /* Note: Rocksoft is a trademark of Rocksoft Pty Ltd, Adelaide, Australia. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
17 /* */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
18 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
19 /* */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
20 /* Implementation Notes */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
21 /* -------------------- */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
22 /* To avoid inconsistencies, the specification of each function is not echoed */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
23 /* here. See the header file for a description of these functions. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
24 /* This package is light on checking because I want to keep it short and */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
25 /* simple and portable (i.e. it would be too messy to distribute my entire */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
26 /* C culture (e.g. assertions package) with this package. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
27 /* */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
28 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
29
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
30 #include "crcmodel.h"
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
31
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
32 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
33
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
34 /* The following definitions make the code more readable. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
35
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
36 #define BITMASK(X) (1L << (X))
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
37 #define MASK32 0xFFFFFFFFL
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
38 #define LOCAL static
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
39
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
40 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
41
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
42 LOCAL ulong reflect P_((ulong v,int b));
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
43 LOCAL ulong reflect (ulong v,int b)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
44 /* Returns the value v with the bottom b [0,32] bits reflected. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
45 /* Example: reflect(0x3e23L,3) == 0x3e26 */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
46 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
47 int i;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
48 ulong t = v;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
49 for (i=0; i<b; i++)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
50 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
51 if (t & 1L)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
52 v|= BITMASK((b-1)-i);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
53 else
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
54 v&= ~BITMASK((b-1)-i);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
55 t>>=1;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
56 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
57 return v;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
58 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
59
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
60 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
61
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
62 LOCAL ulong widmask P_((p_cm_t));
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
63 LOCAL ulong widmask (p_cm_t p_cm)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
64 /* Returns a longword whose value is (2^p_cm->cm_width)-1. */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
65 /* The trick is to do this portably (e.g. without doing <<32). */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
66 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
67 return (((1L<<(p_cm->cm_width-1))-1L)<<1)|1L;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
68 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
69
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
70 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
71
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
72 void cm_ini (p_cm_t p_cm)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
73 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
74 p_cm->cm_reg = p_cm->cm_init;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
75 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
76
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
77 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
78
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
79 void cm_nxt (p_cm_t p_cm, int ch)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
80 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
81 int i;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
82 ulong uch = (ulong) ch;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
83 ulong topbit = BITMASK(p_cm->cm_width-1);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
84
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
85 if (p_cm->cm_refin) uch = reflect(uch,8);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
86 p_cm->cm_reg ^= (uch << (p_cm->cm_width-8));
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
87 for (i=0; i<8; i++)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
88 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
89 if (p_cm->cm_reg & topbit)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
90 p_cm->cm_reg = (p_cm->cm_reg << 1) ^ p_cm->cm_poly;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
91 else
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
92 p_cm->cm_reg <<= 1;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
93 p_cm->cm_reg &= widmask(p_cm);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
94 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
95 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
96
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
97 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
98
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
99 void cm_blk (p_cm_t p_cm,p_ubyte_ blk_adr,ulong blk_len)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
100 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
101 while (blk_len--) cm_nxt(p_cm,*blk_adr++);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
102 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
103
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
104 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
105
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
106 ulong cm_crc (p_cm_t p_cm)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
107 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
108 if (p_cm->cm_refot)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
109 return p_cm->cm_xorot ^ reflect(p_cm->cm_reg,p_cm->cm_width);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
110 else
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
111 return p_cm->cm_xorot ^ p_cm->cm_reg;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
112 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
113
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
114 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
115
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
116 ulong cm_tab (p_cm_t p_cm, int index)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
117 {
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
118 int i;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
119 ulong r;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
120 ulong topbit = BITMASK(p_cm->cm_width-1);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
121 ulong inbyte = (ulong) index;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
122
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
123 if (p_cm->cm_refin) inbyte = reflect(inbyte,8);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
124 r = inbyte << (p_cm->cm_width-8);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
125 for (i=0; i<8; i++)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
126 if (r & topbit)
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
127 r = (r << 1) ^ p_cm->cm_poly;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
128 else
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
129 r<<=1;
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
130 if (p_cm->cm_refin) r = reflect(r,p_cm->cm_width);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
131 return r & widmask(p_cm);
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
132 }
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
133
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
134 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
135 /* End of crcmodel.c */
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
136 /******************************************************************************/
5f11787b4f42 include in ostc4 repository
heinrichsweikamp
parents:
diff changeset
137