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1 | /* | |
2 | * This file is part of the libsigrok project. | |
3 | * | |
4 | * Copyright (C) 2014 Bert Vermeulen <bert@biot.com> | |
5 | * | |
6 | * This program is free software: you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation, either version 3 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <string.h> | |
21 | #include "libsigrok.h" | |
22 | #include "libsigrok-internal.h" | |
23 | ||
24 | /* @cond PRIVATE */ | |
25 | #define LOG_PREFIX "soft-trigger" | |
26 | /* @endcond */ | |
27 | ||
28 | SR_PRIV struct soft_trigger_logic *soft_trigger_logic_new( | |
29 | const struct sr_dev_inst *sdi, struct sr_trigger *trigger) | |
30 | { | |
31 | struct soft_trigger_logic *stl; | |
32 | ||
33 | stl = g_malloc0(sizeof(struct soft_trigger_logic)); | |
34 | stl->sdi = sdi; | |
35 | stl->trigger = trigger; | |
36 | stl->unitsize = (g_slist_length(sdi->channels) + 7) / 8; | |
37 | stl->prev_sample = g_malloc0(stl->unitsize); | |
38 | ||
39 | return stl; | |
40 | } | |
41 | ||
42 | SR_PRIV void soft_trigger_logic_free(struct soft_trigger_logic *stl) | |
43 | { | |
44 | g_free(stl->prev_sample); | |
45 | g_free(stl); | |
46 | } | |
47 | ||
48 | static gboolean logic_check_match(struct soft_trigger_logic *stl, | |
49 | uint8_t *sample, struct sr_trigger_match *match) | |
50 | { | |
51 | int bit, prev_bit; | |
52 | gboolean result; | |
53 | ||
54 | stl->count++; | |
55 | result = FALSE; | |
56 | bit = *(sample + match->channel->index / 8) | |
57 | & (1 << (match->channel->index % 8)); | |
58 | if (match->match == SR_TRIGGER_ZERO) | |
59 | result = bit == 0; | |
60 | else if (match->match == SR_TRIGGER_ONE) | |
61 | result = bit != 0; | |
62 | else { | |
63 | /* Edge matches. */ | |
64 | if (stl->count == 1) | |
65 | /* First sample, don't have enough for an edge match yet. */ | |
66 | return FALSE; | |
67 | prev_bit = *(stl->prev_sample + match->channel->index / 8) | |
68 | & (1 << (match->channel->index % 8)); | |
69 | if (match->match == SR_TRIGGER_RISING) | |
70 | result = prev_bit == 0 && bit != 0; | |
71 | else if (match->match == SR_TRIGGER_FALLING) | |
72 | result = prev_bit != 0 && bit == 0; | |
73 | else if (match->match == SR_TRIGGER_EDGE) | |
74 | result = prev_bit != bit; | |
75 | } | |
76 | ||
77 | return result; | |
78 | } | |
79 | ||
80 | /* Returns the offset (in samples) within buf of where the trigger | |
81 | * occurred, or -1 if not triggered. */ | |
82 | SR_PRIV int soft_trigger_logic_check(struct soft_trigger_logic *stl, | |
83 | uint8_t *buf, int len) | |
84 | { | |
85 | struct sr_datafeed_packet packet; | |
86 | struct sr_trigger_stage *stage; | |
87 | struct sr_trigger_match *match; | |
88 | GSList *l, *l_stage; | |
89 | int offset; | |
90 | int i; | |
91 | gboolean match_found; | |
92 | ||
93 | offset = -1; | |
94 | for (i = 0; i < len; i += stl->unitsize) { | |
95 | l_stage = g_slist_nth(stl->trigger->stages, stl->cur_stage); | |
96 | stage = l_stage->data; | |
97 | if (!stage->matches) | |
98 | /* No matches supplied, client error. */ | |
99 | return SR_ERR_ARG; | |
100 | ||
101 | match_found = TRUE; | |
102 | for (l = stage->matches; l; l = l->next) { | |
103 | match = l->data; | |
104 | if (!match->channel->enabled) | |
105 | /* Ignore disabled channels with a trigger. */ | |
106 | continue; | |
107 | if (!logic_check_match(stl, buf + i, match)) { | |
108 | match_found = FALSE; | |
109 | break; | |
110 | } | |
111 | } | |
112 | memcpy(stl->prev_sample, buf + i, stl->unitsize); | |
113 | if (match_found) { | |
114 | /* Matched on the current stage. */ | |
115 | if (l_stage->next) { | |
116 | /* Advance to next stage. */ | |
117 | stl->cur_stage++; | |
118 | } else { | |
119 | /* Matched on last stage, fire trigger. */ | |
120 | offset = i / stl->unitsize; | |
121 | ||
122 | packet.type = SR_DF_TRIGGER; | |
123 | packet.payload = NULL; | |
124 | sr_session_send(stl->sdi, &packet); | |
125 | break; | |
126 | } | |
127 | } else if (stl->cur_stage > 0) { | |
128 | /* | |
129 | * We had a match at an earlier stage, but failed on the | |
130 | * current stage. However, we may have a match on this | |
131 | * stage in the next bit -- trigger on 0001 will fail on | |
132 | * seeing 00001, so we need to go back to stage 0 -- but | |
133 | * at the next sample from the one that matched originally, | |
134 | * which the counter increment at the end of the loop | |
135 | * takes care of. | |
136 | */ | |
137 | i -= stl->cur_stage * stl->unitsize; | |
138 | if (i < -1) | |
139 | i = -1; /* Oops, went back past this buffer. */ | |
140 | /* Reset trigger stage. */ | |
141 | stl->cur_stage = 0; | |
142 | } | |
143 | } | |
144 | ||
145 | return offset; | |
146 | } | |
147 |