OpenCores
URL https://opencores.org/ocsvn/openrisc/openrisc/trunk

Subversion Repositories openrisc

[/] [openrisc/] [trunk/] [rtos/] [ecos-2.0/] [doc/] [html/] [cdl-guide/] [ref.flavor.html] - Blame information for rev 174

Details | Compare with Previous | View Log

Line No. Rev Author Line
1 28 unneback
<!-- Copyright (C) 2003 Red Hat, Inc.                                -->
2
<!-- This material may be distributed only subject to the terms      -->
3
<!-- and conditions set forth in the Open Publication License, v1.0  -->
4
<!-- or later (the latest version is presently available at          -->
5
<!-- http://www.opencontent.org/openpub/).                           -->
6
<!-- Distribution of the work or derivative of the work in any       -->
7
<!-- standard (paper) book form is prohibited unless prior           -->
8
<!-- permission is obtained from the copyright holder.               -->
9
<HTML
10
><HEAD
11
><TITLE
12
>flavor</TITLE
13
><meta name="MSSmartTagsPreventParsing" content="TRUE">
14
<META
15
NAME="GENERATOR"
16
CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+
17
"><LINK
18
REL="HOME"
19
TITLE="The eCos Component Writer's Guide"
20
HREF="cdl-guide.html"><LINK
21
REL="UP"
22
TITLE="CDL Language Specification"
23
HREF="reference.html"><LINK
24
REL="PREVIOUS"
25
TITLE="doc"
26
HREF="ref.doc.html"><LINK
27
REL="NEXT"
28
TITLE="hardware"
29
HREF="ref.hardware.html"></HEAD
30
><BODY
31
CLASS="REFENTRY"
32
BGCOLOR="#FFFFFF"
33
TEXT="#000000"
34
LINK="#0000FF"
35
VLINK="#840084"
36
ALINK="#0000FF"
37
><DIV
38
CLASS="NAVHEADER"
39
><TABLE
40
SUMMARY="Header navigation table"
41
WIDTH="100%"
42
BORDER="0"
43
CELLPADDING="0"
44
CELLSPACING="0"
45
><TR
46
><TH
47
COLSPAN="3"
48
ALIGN="center"
49
>The <SPAN
50
CLASS="APPLICATION"
51
>eCos</SPAN
52
> Component Writer's Guide</TH
53
></TR
54
><TR
55
><TD
56
WIDTH="10%"
57
ALIGN="left"
58
VALIGN="bottom"
59
><A
60
HREF="ref.doc.html"
61
ACCESSKEY="P"
62
>Prev</A
63
></TD
64
><TD
65
WIDTH="80%"
66
ALIGN="center"
67
VALIGN="bottom"
68
></TD
69
><TD
70
WIDTH="10%"
71
ALIGN="right"
72
VALIGN="bottom"
73
><A
74
HREF="ref.hardware.html"
75
ACCESSKEY="N"
76
>Next</A
77
></TD
78
></TR
79
></TABLE
80
><HR
81
ALIGN="LEFT"
82
WIDTH="100%"></DIV
83
><H1
84
><A
85
NAME="REF.FLAVOR"><SPAN
86
CLASS="PROPERTY"
87
>flavor</SPAN
88
></H1
89
><DIV
90
CLASS="REFNAMEDIV"
91
><A
92
NAME="AEN4315"
93
></A
94
><H2
95
>Name</H2
96
>Property <SPAN
97
CLASS="PROPERTY"
98
>flavor</SPAN
99
>&nbsp;--&nbsp;Specify the nature of a configuration option.</DIV
100
><DIV
101
CLASS="REFSYNOPSISDIV"
102
><A
103
NAME="AEN4319"><H2
104
>Synopsis</H2
105
><TABLE
106
BORDER="5"
107
BGCOLOR="#E0E0F0"
108
WIDTH="70%"
109
><TR
110
><TD
111
><PRE
112
CLASS="SYNOPSIS"
113
>cdl_option &lt;name&gt; {
114
    flavor &lt;flavor&gt;
115
    &#8230;
116
}</PRE
117
></TD
118
></TR
119
></TABLE
120
></DIV
121
><DIV
122
CLASS="REFSECT1"
123
><A
124
NAME="AEN4321"
125
></A
126
><H2
127
>Description</H2
128
><P
129
>The state of a <SPAN
130
CLASS="APPLICATION"
131
>CDL</SPAN
132
> configuration option is a somewhat complicated
133
concept. This state determines what happens when a build tree is
134
generated: it controls what files get built and what
135
<TT
136
CLASS="LITERAL"
137
>#define's</TT
138
> end up in configuration header files. The
139
state also controls the values used during expression evaluation. The
140
key concepts are:</P
141
><P
142
></P
143
><OL
144
TYPE="1"
145
><LI
146
><P
147
>An option may or may not be loaded into the current configuration.
148
However it is still possible for packages to reference options which
149
are not loaded in a <SPAN
150
CLASS="PROPERTY"
151
>requires</SPAN
152
> constraint or other expression. If an
153
option is not loaded then it will have no direct effect on the build
154
process, and <TT
155
CLASS="LITERAL"
156
>0</TT
157
> will be used for expression
158
evaluation. </P
159
></LI
160
><LI
161
><P
162
>Even if an option is loaded it may still be inactive. Usually this is
163
controlled by the option's location in the configuration hierarchy. If
164
an option's parent is active and enabled then the option will normally
165
be active. If the parent is either inactive or disabled then the
166
option will be inactive. For example, if kernel timeslicing is diabled
167
then the option <TT
168
CLASS="LITERAL"
169
>CYGNUM_KERNEL_SCHED_TIMESLICE_TICKS</TT
170
>
171
is irrelevant and must have no effect. The <SPAN
172
CLASS="PROPERTY"
173
>active_if</SPAN
174
> property can be
175
used to specify additional constraints. If an option is inactive then
176
it will have no direct effect on the build process, in other words it
177
will not cause any files to get built or <TT
178
CLASS="LITERAL"
179
>#define's</TT
180
>
181
to be generated. For the purposes of expression evaluation an inactive
182
option has a value of <TT
183
CLASS="LITERAL"
184
>0</TT
185
>.</P
186
></LI
187
><LI
188
><P
189
>An option may be enabled or disabled. Most options are boolean in
190
nature, for example a particular function may get inlined or it may
191
involve a full procedure call. If an option is disabled then it has no
192
direct effect on the build process, and for the purposes of expression
193
evaluation it has a value of 0.</P
194
></LI
195
><LI
196
><P
197
>An option may also have additional data associated with it, for
198
example a numerical value used to control the size of an array.</P
199
></LI
200
></OL
201
><P
202
>Most options are boolean in nature and do not have any additional
203
associated data. For some options only the data part makes sense and
204
users should be unable to manipulate the enabled/disabled part of the
205
state. For a comparatively small number of options it makes sense to
206
have the ability to disable that option or to enable it and associate
207
data as well. Finally, when constructing an option hierarchy it is
208
occasionally useful to have entities which serve only as placeholders.
209
The <SPAN
210
CLASS="PROPERTY"
211
>flavor</SPAN
212
> property can be used to control all this. There are four
213
possible values. It should be noted that the active or inactive state
214
of an option takes priority over the flavor: if an option is inactive
215
then no <TT
216
CLASS="LITERAL"
217
>#define's</TT
218
> will be generated and any
219
build-related properties such as <SPAN
220
CLASS="PROPERTY"
221
>compile</SPAN
222
> will be ignored.</P
223
><P
224
></P
225
><DIV
226
CLASS="VARIABLELIST"
227
><DL
228
><DT
229
>flavor&nbsp;<TT
230
CLASS="LITERAL"
231
>none</TT
232
></DT
233
><DD
234
><P
235
>The <TT
236
CLASS="LITERAL"
237
>none</TT
238
> is intended primarily for placeholder
239
components in the hierarchy, although it can be used for other
240
purposes. Options with this flavor are always enabled and do not have
241
any additional data associated with them, so there is no way for users
242
to modify the option. For the purposes of expression evaluation an
243
option with flavor <TT
244
CLASS="LITERAL"
245
>none</TT
246
> always has the value
247
<TT
248
CLASS="LITERAL"
249
>1</TT
250
>. Normal <TT
251
CLASS="LITERAL"
252
>#define</TT
253
> processing
254
will take place, so typically a single <TT
255
CLASS="LITERAL"
256
>#define</TT
257
> will
258
be generated using the option name and a value of
259
<TT
260
CLASS="LITERAL"
261
>1</TT
262
>. Similarly build-related properties such as
263
<SPAN
264
CLASS="PROPERTY"
265
>compile</SPAN
266
> will take effect.</P
267
></DD
268
><DT
269
>flavor&nbsp;<TT
270
CLASS="LITERAL"
271
>bool</TT
272
></DT
273
><DD
274
><P
275
>Boolean options can be either enabled or disabled, and there is no
276
additional data associated with them. If a boolean option is disabled
277
then no <TT
278
CLASS="LITERAL"
279
>#define</TT
280
> will be generated and any
281
build-related properties such as <SPAN
282
CLASS="PROPERTY"
283
>compile</SPAN
284
> will be ignored. For the
285
purposes of expression evaluation a disabled option has the value
286
<TT
287
CLASS="LITERAL"
288
>0</TT
289
>. If a boolean option is enabled then normal
290
<TT
291
CLASS="LITERAL"
292
>#define</TT
293
> processing will take place, all
294
build-related properties take effect, and the option's value will be
295
<TT
296
CLASS="LITERAL"
297
>1</TT
298
>.</P
299
></DD
300
><DT
301
>flavor&nbsp;<TT
302
CLASS="LITERAL"
303
>data</TT
304
></DT
305
><DD
306
><P
307
>Options with this flavor are always enabled, and have some additional
308
data associated with them which can be edited by the user. This data
309
can be any sequence of characters, although in practice the
310
<SPAN
311
CLASS="PROPERTY"
312
>legal_values</SPAN
313
> property will often be used to impose constraints. In
314
appropriate contexts such as expressions the configuration tools will
315
attempt to interpret the data as integer or floating point numbers.
316
Since an option with the <TT
317
CLASS="LITERAL"
318
>data</TT
319
> flavor cannot be
320
disabled, normal <TT
321
CLASS="LITERAL"
322
>#define</TT
323
> processing takes place and
324
the data will be used for the value. Similarly all build-related
325
properties take effect, and the option's value for the purposes of
326
expression evaluation is the data.</P
327
></DD
328
><DT
329
>flavor&nbsp;<TT
330
CLASS="LITERAL"
331
>booldata</TT
332
></DT
333
><DD
334
><P
335
>This combines the <TT
336
CLASS="LITERAL"
337
>bool</TT
338
> and <TT
339
CLASS="LITERAL"
340
>data</TT
341
>
342
flavors. The option may be enabled or disabled, and in addition the
343
option has some associated data. If the option is disabled then no
344
<TT
345
CLASS="LITERAL"
346
>#define</TT
347
> will be generated, the build-related
348
properties have no effect, and for the purposes of expression
349
evaluation the option's value is <TT
350
CLASS="LITERAL"
351
>0</TT
352
>. If the option
353
is enabled then a <TT
354
CLASS="LITERAL"
355
>#define</TT
356
> will be generated using
357
the data as the value, all build-related properties take effect, and
358
the option's value for the purposes of expression evaluation is the
359
data. If <TT
360
CLASS="LITERAL"
361
>0</TT
362
> is legal data then it is not possible to
363
distinguish this case from the option being disabled or inactive.</P
364
></DD
365
></DL
366
></DIV
367
><P
368
>Options and components have the <TT
369
CLASS="LITERAL"
370
>bool</TT
371
> flavor by
372
default, but this can be changed as desired. Packages always have the
373
<TT
374
CLASS="LITERAL"
375
>booldata</TT
376
> flavor, and this cannot be changed.
377
Interfaces have the <TT
378
CLASS="LITERAL"
379
>data</TT
380
> flavor by default, since
381
the value of an interface is a count of the number of active and
382
enabled interfaces, but they can be given the <TT
383
CLASS="LITERAL"
384
>bool</TT
385
>
386
or <TT
387
CLASS="LITERAL"
388
>booldata</TT
389
> flavors.</P
390
><DIV
391
CLASS="NOTE"
392
><BLOCKQUOTE
393
CLASS="NOTE"
394
><P
395
><B
396
>Note: </B
397
>The expression syntax needs to be extended to allow the loaded,
398
active, enabled and data aspects of an option's state to be examined
399
individually. This would allow component writers to distinguish
400
between a disabled <TT
401
CLASS="LITERAL"
402
>booldata</TT
403
> option and an enabled
404
one which has a value of <TT
405
CLASS="LITERAL"
406
>0</TT
407
>. Such an enhancement to
408
the expression syntax may also prove useful in other circumstances.</P
409
></BLOCKQUOTE
410
></DIV
411
></DIV
412
><DIV
413
CLASS="REFSECT1"
414
><A
415
NAME="AEN4397"
416
></A
417
><H2
418
>Example</H2
419
><TABLE
420
BORDER="5"
421
BGCOLOR="#E0E0F0"
422
WIDTH="70%"
423
><TR
424
><TD
425
><PRE
426
CLASS="PROGRAMLISTING"
427
>&#13;cdl_component CYGPKG_LIBM_COMPATIBILITY {
428
 
429
    cdl_component CYGNUM_LIBM_COMPATIBILITY {
430
        flavor booldata
431
        &#8230;
432
 
433
        cdl_option CYGNUM_LIBM_COMPAT_DEFAULT {
434
            flavor data
435
            &#8230;
436
        }
437
    }
438
 
439
    &#8230;
440
}
441
 
442
cdl_component CYGPKG_LIBM_TRACE {
443
    flavor        bool
444
    &#8230;
445
}</PRE
446
></TD
447
></TR
448
></TABLE
449
></DIV
450
><DIV
451
CLASS="REFSECT1"
452
><A
453
NAME="AEN4400"
454
></A
455
><H2
456
>See Also</H2
457
><P
458
>Properties <A
459
HREF="ref.calculated.html"
460
><SPAN
461
CLASS="PROPERTY"
462
>calculated</SPAN
463
></A
464
>,
465
<A
466
HREF="ref.default-value.html"
467
><SPAN
468
CLASS="PROPERTY"
469
>default_value</SPAN
470
></A
471
> and
472
<A
473
HREF="ref.legal-values.html"
474
><SPAN
475
CLASS="PROPERTY"
476
>legal_values</SPAN
477
></A
478
>,</P
479
></DIV
480
><DIV
481
CLASS="NAVFOOTER"
482
><HR
483
ALIGN="LEFT"
484
WIDTH="100%"><TABLE
485
SUMMARY="Footer navigation table"
486
WIDTH="100%"
487
BORDER="0"
488
CELLPADDING="0"
489
CELLSPACING="0"
490
><TR
491
><TD
492
WIDTH="33%"
493
ALIGN="left"
494
VALIGN="top"
495
><A
496
HREF="ref.doc.html"
497
ACCESSKEY="P"
498
>Prev</A
499
></TD
500
><TD
501
WIDTH="34%"
502
ALIGN="center"
503
VALIGN="top"
504
><A
505
HREF="cdl-guide.html"
506
ACCESSKEY="H"
507
>Home</A
508
></TD
509
><TD
510
WIDTH="33%"
511
ALIGN="right"
512
VALIGN="top"
513
><A
514
HREF="ref.hardware.html"
515
ACCESSKEY="N"
516
>Next</A
517
></TD
518
></TR
519
><TR
520
><TD
521
WIDTH="33%"
522
ALIGN="left"
523
VALIGN="top"
524
><SPAN
525
CLASS="PROPERTY"
526
>doc</SPAN
527
></TD
528
><TD
529
WIDTH="34%"
530
ALIGN="center"
531
VALIGN="top"
532
><A
533
HREF="reference.html"
534
ACCESSKEY="U"
535
>Up</A
536
></TD
537
><TD
538
WIDTH="33%"
539
ALIGN="right"
540
VALIGN="top"
541
><SPAN
542
CLASS="PROPERTY"
543
>hardware</SPAN
544
></TD
545
></TR
546
></TABLE
547
></DIV
548
></BODY
549
></HTML
550
>

powered by: WebSVN 2.1.0

© copyright 1999-2024 OpenCores.org, equivalent to Oliscience, all rights reserved. OpenCores®, registered trademark.