Wiki source code of EPICS

Last modified by Sebastian Marsching on 2023/02/27 22:56
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1 {{toc/}}
2
3 # EPICS Base
4
5 ## Extracting the upper 32 bits from a 64-bit integer
6
7 Sometimes, it is necessary to extract individual bits from a 64-bit integer (e.g. one that is read from a hardware register through the `int64in` record). This is possible through some calc record magic.
8
9 Please note that this depends on some internal casting behavior, so it might not work on all platforms. It has been tested to work successfully with EPICS Base 7.0.6 running x86_64 Linux, but it seems like it does not work with the same version of EPICS running on ARM Linux.
10
11 record(int64in, "$(P)$(R)MyRegister") {
12 field(FLNK, "$(P)$(R)MyRegister:Low")
13 }
14
15 record(mbbiDirect, "$(P)$(R)MyRegister:Low") {
16 field(DTYP, "stream")
17 field(INP, "$(P)$(R)MyRegister MSI")
18 field(FLNK, "$(P)$(R)MyRegister:CalcHigh")
19 }
20
21 # This looks a bit strange, but it is a reliable way of extracting the upper
22 # 32 bits of the 64 bit register. This works, because the value is implicitly
23 # converted to a double, which preserves the upper 52 bits of the original
24 # value. From this value, we have to substract the unsigned value of the lower
25 # 32 bits (if we didn’t do this, we would get an off-by-one error under certain
26 # circumstances due to rounding), and then we can right-shift by 32 bits (which
27 # we have to do through division for a floating point number). Finally, we cut
28 # off any fractional parts that might be left due to rounding.
29 record(calc, "$(P)$(R)MyRegister:CalcHigh") {
30 field(CALC, "FLOOR((A-(B+((B<0)?(2^32):0)))/(2^32))")
31 field(INPA, "$(P)$(R)MyRegister MSI")
32 field(INPB, "$(P)$(R)MyRegister:Low MSI")
33 field(FLNK, "$(P)$(R)MyRegister:High")
34 }
35
36 record(mbbiDirect, "$(P)$(R)MyRegister:High") {
37 field(DTYP, "stream")
38 field(INP, "$(P)$(R)MyRegister:CalcHigh MSI")
39 }
40
41 # EDM
42
43 In addition to the dependencies for MEDM I had to install the following packages:
44
45 * libgif-dev
46 * libpng-dev
47 * libxtst-dev
48
49 Under Ubuntu 14.04 LTS I had to modify the file `extensions/configure/os/CONFIG_SITE.linux-x86_64.linux-x86_64` in order to make `X11_LIB` and `MOTIF_LIB` to point to `/usr/lib/x86_64-linux-gnu`. In addition to that I had to modify the file `edmMain/Makefile` and add the line `USR_LDFLAGS_Linux += -Wl,--no-as-needed` as described on the [EPICS mailing-list](http://www.aps.anl.gov/epics/tech-talk/2012/msg01723.php).
50
51 # MEDM
52
53 ## Compiling MEDM on Ubuntu 10.04 LTS (lucid lynx)
54
55 If EPICS base is installed in `/my/epics/path/base`, you should extract the [EPICS extensions top directory bundle](http://www.aps.anl.gov/epics/download/extensions/extensionsTop_20070703.tar.gz) to `/my/epics/path`, so that a new directory `/my/epics/path/extensions` is created. The [MEDM source archive](http://www.aps.anl.gov/epics/download/extensions/medm3_1_5.tar.gz) should be extracted to `/my/epics/path/extensions/src`. You should then switch to `/my/epics/path/extensions/src/medm3_1_5` and run `make`.
56
57 In addition to a lot of development packages I had already installed, I had to install the following packages:
58
59 * libmotif-dev
60 * libxmu-dev
61 * libxp-dev
62 * libxt-dev
63 * x11proto-print-dev
64
65 # synApps
66
67 ## Compiling synApps on Ubuntu 10.04 LTS (lucid lynx)
68
69 In order to compile synApps 5.5 on Ubuntu 10.04 LTS, I had to install the following packages (other packages might be needed as well):
70
71 * flex
72 * libusb-dev
73
74 In order to compile synApps 5.6 on Ubuntu 10.04 LTS, I had to install the following packages (other packages might be needed as well):
75
76 * re2c
77 * libbz2-dev
78 * libfreetype6-dev
79 * libpng-dev
80 * libusb-dev
81 * libxext-dev
82 * libxml2-dev
83
84 # StripTool
85
86 In addition to the dependencies listed for EDM and MEDM I had to install the following packages:
87
88 * libxpm-dev
89
90 # Asyn
91
92 ## Codes for Tracing I/O Operations
93
94 ```c
95 /* traceMask definitions*/
96 #define ASYN_TRACE_ERROR 0x0001
97 #define ASYN_TRACEIO_DEVICE 0x0002
98 #define ASYN_TRACEIO_FILTER 0x0004
99 #define ASYN_TRACEIO_DRIVER 0x0008
100 #define ASYN_TRACE_FLOW 0x0010
101
102 /* traceIO mask definitions*/
103 #define ASYN_TRACEIO_NODATA 0x0000
104 #define ASYN_TRACEIO_ASCII 0x0001
105 #define ASYN_TRACEIO_ESCAPE 0x0002
106 #define ASYN_TRACEIO_HEX 0x0004
107 ```