1ADB(1) General Commands Manual ADB(1)
2
6 adb - debugger
7
9 adb [-w] [ objfil [ corfil ] ]
10
12 Adb is a general purpose debugging program. It may be used to examine
13 files and to provide a controlled environment for the execution of UNIX
14 programs.
15 Objfil is normally an executable program file, preferably containing a
17 symbol table; if not then the symbolic features of adb cannot be used
18 although the file can still be examined. The default for objfil is
19 a.out. Corfil is assumed to be a core image file produced after exe‐
20 cuting objfil; the default for corfil is core.
21 Requests to adb are read from the standard input and responses are to
23 the standard output. If the -w flag is present then both objfil and
24 corfil are created if necessary and opened for reading and writing so
25 that files can be modified using adb. Adb ignores QUIT; INTERRUPT
26 causes return to the next adb command.
27 In general requests to adb are of the form
29 [address] [, count] [command] [;]
31 If address is present then dot is set to address. Initially dot is set
33 to 0. For most commands count specifies how many times the command
34 will be executed. The default count is 1. Address and count are
35 expressions.
36 The interpretation of an address depends on the context it is used in.
38 If a subprocess is being debugged then addresses are interpreted in the
39 usual way in the address space of the subprocess. For further details
40 of address mapping see ADDRESSES.
41
43 . The value of dot.
44 + The value of dot incremented by the current increment.
46 ^ The value of dot decremented by the current increment.
48 " The last address typed.
50 integer
52 An octal number if integer begins with a 0; a hexadecimal number
53 if preceded by #; otherwise a decimal number.
54 integer.fraction
56 A 32 bit floating point number.
57 ´cccc´ The ASCII value of up to 4 characters. \ may be used to escape
59 a ´.
60 < name The value of name, which is either a variable name or a register
62 name. Adb maintains a number of variables (see VARIABLES) named
63 by single letters or digits. If name is a register name then
64 the value of the register is obtained from the system header in
65 corfil. The register names are r0 ... r5 sp pc ps.
66 symbol A symbol is a sequence of upper or lower case letters, under‐
68 scores or digits, not starting with a digit. \f[R] may be used
69 to escape other characters. The value of the symbol is taken
70 from the symbol table in objfil. An initial _ or ~ will be
71 prepended to symbol if needed.
72 _ symbol
74 In C, the `true name' of an external symbol begins with _. It
75 may be necessary to utter this name to disinguish it from inter‐
76 nal or hidden variables of a program.
77 routine.name
79 The address of the variable name in the specified C routine.
80 Both routine and name are symbols. If name is omitted the value
81 is the address of the most recently activated C stack frame cor‐
82 responding to routine.
83 (exp) The value of the expression exp.
85 Monadic operators
87 *exp The contents of the location addressed by exp in corfil.
89 @exp The contents of the location addressed by exp in objfil.
91 -exp Integer negation.
93 ~exp Bitwise complement.
95 Dyadic operators are left associative and are less binding than monadic
97 operators.
98 e1+e2 Integer addition.
100 e1-e2 Integer subtraction.
102 e1*e2 Integer multiplication.
104 e1%e2 Integer division.
106 e1&e2 Bitwise conjunction.
108 e1⎪e2 Bitwise disjunction.
110 e1#e2 E1 rounded up to the next multiple of e2.
112
114 Most commands consist of a verb followed by a modifier or list of modi‐
115 fiers. The following verbs are available. (The commands `?' and `/'
116 may be followed by `*'; see ADDRESSES for further details.)
117 ?f Locations starting at address in objfil are printed according to
119 the format f.
120 /f Locations starting at address in corfil are printed according to
122 the format f.
123 =f The value of address itself is printed in the styles indicated by
125 the format f. (For i format `?' is printed for the parts of the
126 instruction that reference subsequent words.)
127 A format consists of one or more characters that specify a style of
129 printing. Each format character may be preceded by a decimal integer
130 that is a repeat count for the format character. While stepping
131 through a format dot is incremented temporarily by the amount given for
132 each format letter. If no format is given then the last format is
133 used. The format letters available are as follows.
134 o 2 Print 2 bytes in octal. All octal numbers output by adb
136 are preceded by 0.
137 O 4 Print 4 bytes in octal.
138 q 2 Print in signed octal.
139 Q 4 Print long signed octal.
140 d 2 Print in decimal.
141 D 4 Print long decimal.
142 x 2 Print 2 bytes in hexadecimal.
143 X 4 Print 4 bytes in hexadecimal.
144 u 2 Print as an unsigned decimal number.
145 U 4 Print long unsigned decimal.
146 f 4 Print the 32 bit value as a floating point number.
147 F 8 Print double floating point.
148 b 1 Print the addressed byte in octal.
149 c 1 Print the addressed character.
150 C 1 Print the addressed character using the following escape
151 convention. Character values 000 to 040 are printed as @
152 followed by the corresponding character in the range 0100
153 to 0140. The character @ is printed as @@.
154 s n Print the addressed characters until a zero character is
155 reached.
156 S n Print a string using the @ escape convention. n is the
157 length of the string including its zero terminator.
158 Y 4 Print 4 bytes in date format (see ctime(3)).
159 i n Print as PDP11 instructions. n is the number of bytes
160 occupied by the instruction. This style of printing
161 causes variables 1 and 2 to be set to the offset parts of
162 the source and destination respectively.
163 a 0 Print the value of dot in symbolic form. Symbols are
164 checked to ensure that they have an appropriate type as
165 indicated below.
166 / local or global data symbol
168 ? local or global text symbol
169 = local or global absolute symbol
170 p 2 Print the addressed value in symbolic form using the same
172 rules for symbol lookup as a.
173 t 0 When preceded by an integer tabs to the next appropriate
174 tab stop. For example, 8t moves to the next 8-space tab
175 stop.
176 r 0 Print a space.
177 n 0 Print a newline.
178 "..." 0
179 Print the enclosed string.
180 ^ Dot is decremented by the current increment. Nothing is
181 printed.
182 + Dot is incremented by 1. Nothing is printed.
183 - Dot is decremented by 1. Nothing is printed.
184 newline
186 If the previous command temporarily incremented dot, make the
187 increment permanent. Repeat the previous command with a count
188 of 1.
189 [?/]l value mask
191 Words starting at dot are masked with mask and compared with
192 value until a match is found. If L is used then the match is
193 for 4 bytes at a time instead of 2. If no match is found then
194 dot is unchanged; otherwise dot is set to the matched location.
195 If mask is omitted then -1 is used.
196 [?/]w value ...
198 Write the 2-byte value into the addressed location. If the com‐
199 mand is W, write 4 bytes. Odd addresses are not allowed when
200 writing to the subprocess address space.
201 [?/]m b1 e1 f1[?/]
203 New values for (b1, e1, f1) are recorded. If less than three
204 expressions are given then the remaining map parameters are left
205 unchanged. If the `?' or `/' is followed by `*' then the second
206 segment (b2,e2,f2) of the mapping is changed. If the list is
207 terminated by `?' or `/' then the file (objfil or corfil respec‐
208 tively) is used for subsequent requests. (So that, for example,
209 `/m?' will cause `/' to refer to objfil.)
210 >name Dot is assigned to the variable or register named.
212 ! A shell is called to read the rest of the line following `!'.
214 $modifier
216 Miscellaneous commands. The available modifiers are:
217 <f Read commands from the file f and return.
219 >f Send output to the file f, which is created if it does
220 not exist.
221 r Print the general registers and the instruction addressed
222 by pc. Dot is set to pc.
223 f Print the floating registers in single or double length.
224 If the floating point status of ps is set to double (0200
225 bit) then double length is used anyway.
226 b Print all breakpoints and their associated counts and
227 commands.
228 a ALGOL 68 stack backtrace. If address is given then it is
229 taken to be the address of the current frame (instead of
230 r4). If count is given then only the first count frames
231 are printed.
232 c C stack backtrace. If address is given then it is taken
233 as the address of the current frame (instead of r5). If
234 C is used then the names and (16 bit) values of all auto‐
235 matic and static variables are printed for each active
236 function. If count is given then only the first count
237 frames are printed.
238 e The names and values of external variables are printed.
239 w Set the page width for output to address (default 80).
240 s Set the limit for symbol matches to address (default
241 255).
242 o All integers input are regarded as octal.
243 d Reset integer input as described in EXPRESSIONS.
244 q Exit from adb.
245 v Print all non zero variables in octal.
246 m Print the address map.
247 :modifier
249 Manage a subprocess. Available modifiers are:
250 bc Set breakpoint at address. The breakpoint is executed
252 count-1 times before causing a stop. Each time the
253 breakpoint is encountered the command c is executed. If
254 this command sets dot to zero then the breakpoint causes
255 a stop.
256 d Delete breakpoint at address.
258 r Run objfil as a subprocess. If address is given explic‐
260 itly then the program is entered at this point; otherwise
261 the program is entered at its standard entry point.
262 count specifies how many breakpoints are to be ignored
263 before stopping. Arguments to the subprocess may be sup‐
264 plied on the same line as the command. An argument
265 starting with < or > causes the standard input or output
266 to be established for the command. All signals are
267 turned on on entry to the subprocess.
268 cs The subprocess is continued with signal s c s, see sig‐
270 nal(2). If address is given then the subprocess is con‐
271 tinued at this address. If no signal is specified then
272 the signal that caused the subprocess to stop is sent.
273 Breakpoint skipping is the same as for r.
274 ss As for c except that the subprocess is single stepped
276 count times. If there is no current subprocess then obj‐
277 fil is run as a subprocess as for r. In this case no
278 signal can be sent; the remainder of the line is treated
279 as arguments to the subprocess.
280 k The current subprocess, if any, is terminated.
282
284 Adb provides a number of variables. Named variables are set initially
285 by adb but are not used subsequently. Numbered variables are reserved
286 for communication as follows.
287 0 The last value printed.
289 1 The last offset part of an instruction source.
290 2 The previous value of variable 1.
291 On entry the following are set from the system header in the corfil.
293 If corfil does not appear to be a core file then these values are set
294 from objfil.
295 b The base address of the data segment.
297 d The data segment size.
298 e The entry point.
299 m The `magic' number (0405, 0407, 0410 or 0411).
300 s The stack segment size.
301 t The text segment size.
302
304 The address in a file associated with a written address is determined
305 by a mapping associated with that file. Each mapping is represented by
306 two triples (b1, e1, f1) and (b2, e2, f2) and the file address corre‐
307 sponding to a written address is calculated as follows.
308 b1≤address<e1 => file address=address+f1-b1, otherwise,
310 b2≤address<e2 => file address=address+f2-b2,
312 otherwise, the requested address is not legal. In some cases (e.g. for
314 programs with separated I and D space) the two segments for a file may
315 overlap. If a ? or / is followed by an * then only the second triple
316 is used.
317 The initial setting of both mappings is suitable for normal a.out and
319 core files. If either file is not of the kind expected then, for that
320 file, b1 is set to 0, e1 is set to the maximum file size and f1 is set
321 to 0; in this way the whole file can be examined with no address trans‐
322 lation.
323 So that adb may be used on large files all appropriate values are kept
325 as signed 32 bit integers.
326
328 /dev/mem
329 /dev/swap
330 a.out
331 core
332
334 ptrace(2), a.out(5), core(5)
335
337 `Adb' when there is no current command or format. Comments about inac‐
338 cessible files, syntax errors, abnormal termination of commands, etc.
339 Exit status is 0, unless last command failed or returned nonzero sta‐
340 tus.
341
343 A breakpoint set at the entry point is not effective on initial entry
344 to the program.
345 When single stepping, system calls do not count as an executed instruc‐
346 tion.
347 Local variables whose names are the same as an external variable may
348 foul up the accessing of the external.
349 ADB(1)