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| <a name="GDB%2fMI-Data-Manipulation"></a> |
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| <p> |
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| |
| <h3 class="section">27.16 <span class="sc">gdb/mi</span> Data Manipulation</h3> |
| |
| <p><a name="index-data-manipulation_002c-in-_0040sc_007bgdb_002fmi_007d-3046"></a><a name="index-g_t_0040sc_007bgdb_002fmi_007d_002c-data-manipulation-3047"></a>This section describes the <span class="sc">gdb/mi</span> commands that manipulate data: |
| examine memory and registers, evaluate expressions, etc. |
| |
| <p>For details about what an addressable memory unit is, |
| see <a href="addressable-memory-unit.html#addressable-memory-unit">addressable memory unit</a>. |
| |
| <!-- REMOVED FROM THE INTERFACE. --> |
| <!-- @subheading -data-assign --> |
| <!-- Change the value of a program variable. Plenty of side effects. --> |
| <!-- @subsubheading GDB Command --> |
| <!-- set variable --> |
| <!-- @subsubheading Example --> |
| <!-- N.A. --> |
| <h4 class="subheading">The <code>-data-disassemble</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002ddisassemble-3048"></a> |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-disassemble |
| [ -s <var>start-addr</var> -e <var>end-addr</var> ] |
| | [ -a <var>addr</var> ] |
| | [ -f <var>filename</var> -l <var>linenum</var> [ -n <var>lines</var> ] ] |
| -- <var>mode</var> |
| </pre> |
| <p class="noindent">Where: |
| |
| <dl> |
| <dt>‘<samp><var>start-addr</var></samp>’<dd>is the beginning address (or <code>$pc</code>) |
| <br><dt>‘<samp><var>end-addr</var></samp>’<dd>is the end address |
| <br><dt>‘<samp><var>addr</var></samp>’<dd>is an address anywhere within (or the name of) the function to |
| disassemble. If an address is specified, the whole function |
| surrounding that address will be disassembled. If a name is |
| specified, the whole function with that name will be disassembled. |
| <br><dt>‘<samp><var>filename</var></samp>’<dd>is the name of the file to disassemble |
| <br><dt>‘<samp><var>linenum</var></samp>’<dd>is the line number to disassemble around |
| <br><dt>‘<samp><var>lines</var></samp>’<dd>is the number of disassembly lines to be produced. If it is -1, |
| the whole function will be disassembled, in case no <var>end-addr</var> is |
| specified. If <var>end-addr</var> is specified as a non-zero value, and |
| <var>lines</var> is lower than the number of disassembly lines between |
| <var>start-addr</var> and <var>end-addr</var>, only <var>lines</var> lines are |
| displayed; if <var>lines</var> is higher than the number of lines between |
| <var>start-addr</var> and <var>end-addr</var>, only the lines up to <var>end-addr</var> |
| are displayed. |
| <br><dt>‘<samp><var>mode</var></samp>’<dd>is one of: |
| <ul> |
| <li>0 disassembly only |
| <li>1 mixed source and disassembly (deprecated) |
| <li>2 disassembly with raw opcodes |
| <li>3 mixed source and disassembly with raw opcodes (deprecated) |
| <li>4 mixed source and disassembly |
| <li>5 mixed source and disassembly with raw opcodes |
| </ul> |
| |
| <p>Modes 1 and 3 are deprecated. The output is “source centric” |
| which hasn't proved useful in practice. |
| See <a href="Machine-Code.html#Machine-Code">Machine Code</a>, for a discussion of the difference between |
| <code>/m</code> and <code>/s</code> output of the <code>disassemble</code> command. |
| </dl> |
| |
| <h5 class="subsubheading">Result</h5> |
| |
| <p>The result of the <code>-data-disassemble</code> command will be a list named |
| ‘<samp><span class="samp">asm_insns</span></samp>’, the contents of this list depend on the <var>mode</var> |
| used with the <code>-data-disassemble</code> command. |
| |
| <p>For modes 0 and 2 the ‘<samp><span class="samp">asm_insns</span></samp>’ list contains tuples with the |
| following fields: |
| |
| <dl> |
| <dt><code>address</code><dd>The address at which this instruction was disassembled. |
| |
| <br><dt><code>func-name</code><dd>The name of the function this instruction is within. |
| |
| <br><dt><code>offset</code><dd>The decimal offset in bytes from the start of ‘<samp><span class="samp">func-name</span></samp>’. |
| |
| <br><dt><code>inst</code><dd>The text disassembly for this ‘<samp><span class="samp">address</span></samp>’. |
| |
| <br><dt><code>opcodes</code><dd>This field is only present for modes 2, 3 and 5. This contains the raw opcode |
| bytes for the ‘<samp><span class="samp">inst</span></samp>’ field. |
| |
| </dl> |
| |
| <p>For modes 1, 3, 4 and 5 the ‘<samp><span class="samp">asm_insns</span></samp>’ list contains tuples named |
| ‘<samp><span class="samp">src_and_asm_line</span></samp>’, each of which has the following fields: |
| |
| <dl> |
| <dt><code>line</code><dd>The line number within ‘<samp><span class="samp">file</span></samp>’. |
| |
| <br><dt><code>file</code><dd>The file name from the compilation unit. This might be an absolute |
| file name or a relative file name depending on the compile command |
| used. |
| |
| <br><dt><code>fullname</code><dd>Absolute file name of ‘<samp><span class="samp">file</span></samp>’. It is converted to a canonical form |
| using the source file search path |
| (see <a href="Source-Path.html#Source-Path">Specifying Source Directories</a>) |
| and after resolving all the symbolic links. |
| |
| <p>If the source file is not found this field will contain the path as |
| present in the debug information. |
| |
| <br><dt><code>line_asm_insn</code><dd>This is a list of tuples containing the disassembly for ‘<samp><span class="samp">line</span></samp>’ in |
| ‘<samp><span class="samp">file</span></samp>’. The fields of each tuple are the same as for |
| <code>-data-disassemble</code> in <var>mode</var> 0 and 2, so ‘<samp><span class="samp">address</span></samp>’, |
| ‘<samp><span class="samp">func-name</span></samp>’, ‘<samp><span class="samp">offset</span></samp>’, ‘<samp><span class="samp">inst</span></samp>’, and optionally |
| ‘<samp><span class="samp">opcodes</span></samp>’. |
| |
| </dl> |
| |
| <p>Note that whatever included in the ‘<samp><span class="samp">inst</span></samp>’ field, is not |
| manipulated directly by <span class="sc">gdb/mi</span>, i.e., it is not possible to |
| adjust its format. |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p>The corresponding <span class="sc">gdb</span> command is ‘<samp><span class="samp">disassemble</span></samp>’. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <p>Disassemble from the current value of <code>$pc</code> to <code>$pc + 20</code>: |
| |
| <pre class="smallexample"> (gdb) |
| -data-disassemble -s $pc -e "$pc + 20" -- 0 |
| ^done, |
| asm_insns=[ |
| {address="0x000107c0",func-name="main",offset="4", |
| inst="mov 2, %o0"}, |
| {address="0x000107c4",func-name="main",offset="8", |
| inst="sethi %hi(0x11800), %o2"}, |
| {address="0x000107c8",func-name="main",offset="12", |
| inst="or %o2, 0x140, %o1\t! 0x11940 <_lib_version+8>"}, |
| {address="0x000107cc",func-name="main",offset="16", |
| inst="sethi %hi(0x11800), %o2"}, |
| {address="0x000107d0",func-name="main",offset="20", |
| inst="or %o2, 0x168, %o4\t! 0x11968 <_lib_version+48>"}] |
| (gdb) |
| </pre> |
| <p>Disassemble the whole <code>main</code> function. Line 32 is part of |
| <code>main</code>. |
| |
| <pre class="smallexample"> -data-disassemble -f basics.c -l 32 -- 0 |
| ^done,asm_insns=[ |
| {address="0x000107bc",func-name="main",offset="0", |
| inst="save %sp, -112, %sp"}, |
| {address="0x000107c0",func-name="main",offset="4", |
| inst="mov 2, %o0"}, |
| {address="0x000107c4",func-name="main",offset="8", |
| inst="sethi %hi(0x11800), %o2"}, |
| [...] |
| {address="0x0001081c",func-name="main",offset="96",inst="ret "}, |
| {address="0x00010820",func-name="main",offset="100",inst="restore "}] |
| (gdb) |
| </pre> |
| <p>Disassemble 3 instructions from the start of <code>main</code>: |
| |
| <pre class="smallexample"> (gdb) |
| -data-disassemble -f basics.c -l 32 -n 3 -- 0 |
| ^done,asm_insns=[ |
| {address="0x000107bc",func-name="main",offset="0", |
| inst="save %sp, -112, %sp"}, |
| {address="0x000107c0",func-name="main",offset="4", |
| inst="mov 2, %o0"}, |
| {address="0x000107c4",func-name="main",offset="8", |
| inst="sethi %hi(0x11800), %o2"}] |
| (gdb) |
| </pre> |
| <p>Disassemble 3 instructions from the start of <code>main</code> in mixed mode: |
| |
| <pre class="smallexample"> (gdb) |
| -data-disassemble -f basics.c -l 32 -n 3 -- 1 |
| ^done,asm_insns=[ |
| src_and_asm_line={line="31", |
| file="../../../src/gdb/testsuite/gdb.mi/basics.c", |
| fullname="/absolute/path/to/src/gdb/testsuite/gdb.mi/basics.c", |
| line_asm_insn=[{address="0x000107bc", |
| func-name="main",offset="0",inst="save %sp, -112, %sp"}]}, |
| src_and_asm_line={line="32", |
| file="../../../src/gdb/testsuite/gdb.mi/basics.c", |
| fullname="/absolute/path/to/src/gdb/testsuite/gdb.mi/basics.c", |
| line_asm_insn=[{address="0x000107c0", |
| func-name="main",offset="4",inst="mov 2, %o0"}, |
| {address="0x000107c4",func-name="main",offset="8", |
| inst="sethi %hi(0x11800), %o2"}]}] |
| (gdb) |
| </pre> |
| <h4 class="subheading">The <code>-data-evaluate-expression</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002devaluate_002dexpression-3049"></a> |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-evaluate-expression <var>expr</var> |
| </pre> |
| <p>Evaluate <var>expr</var> as an expression. The expression could contain an |
| inferior function call. The function call will execute synchronously. |
| If the expression contains spaces, it must be enclosed in double quotes. |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p>The corresponding <span class="sc">gdb</span> commands are ‘<samp><span class="samp">print</span></samp>’, ‘<samp><span class="samp">output</span></samp>’, and |
| ‘<samp><span class="samp">call</span></samp>’. In <code>gdbtk</code> only, there's a corresponding |
| ‘<samp><span class="samp">gdb_eval</span></samp>’ command. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <p>In the following example, the numbers that precede the commands are the |
| <dfn>tokens</dfn> described in <a href="GDB_002fMI-Command-Syntax.html#GDB_002fMI-Command-Syntax"><span class="sc">gdb/mi</span> Command Syntax</a>. Notice how <span class="sc">gdb/mi</span> returns the same tokens in its |
| output. |
| |
| <pre class="smallexample"> 211-data-evaluate-expression A |
| 211^done,value="1" |
| (gdb) |
| 311-data-evaluate-expression &A |
| 311^done,value="0xefffeb7c" |
| (gdb) |
| 411-data-evaluate-expression A+3 |
| 411^done,value="4" |
| (gdb) |
| 511-data-evaluate-expression "A + 3" |
| 511^done,value="4" |
| (gdb) |
| </pre> |
| <h4 class="subheading">The <code>-data-list-changed-registers</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002dlist_002dchanged_002dregisters-3050"></a> |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-list-changed-registers |
| </pre> |
| <p>Display a list of the registers that have changed. |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p><span class="sc">gdb</span> doesn't have a direct analog for this command; <code>gdbtk</code> |
| has the corresponding command ‘<samp><span class="samp">gdb_changed_register_list</span></samp>’. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <p>On a PPC MBX board: |
| |
| <pre class="smallexample"> (gdb) |
| -exec-continue |
| ^running |
| |
| (gdb) |
| *stopped,reason="breakpoint-hit",disp="keep",bkptno="1",frame={ |
| func="main",args=[],file="try.c",fullname="/home/foo/bar/try.c", |
| line="5",arch="powerpc"} |
| (gdb) |
| -data-list-changed-registers |
| ^done,changed-registers=["0","1","2","4","5","6","7","8","9", |
| "10","11","13","14","15","16","17","18","19","20","21","22","23", |
| "24","25","26","27","28","30","31","64","65","66","67","69"] |
| (gdb) |
| </pre> |
| <h4 class="subheading">The <code>-data-list-register-names</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002dlist_002dregister_002dnames-3051"></a> |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-list-register-names [ ( <var>regno</var> )+ ] |
| </pre> |
| <p>Show a list of register names for the current target. If no arguments |
| are given, it shows a list of the names of all the registers. If |
| integer numbers are given as arguments, it will print a list of the |
| names of the registers corresponding to the arguments. To ensure |
| consistency between a register name and its number, the output list may |
| include empty register names. |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p><span class="sc">gdb</span> does not have a command which corresponds to |
| ‘<samp><span class="samp">-data-list-register-names</span></samp>’. In <code>gdbtk</code> there is a |
| corresponding command ‘<samp><span class="samp">gdb_regnames</span></samp>’. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <p>For the PPC MBX board: |
| <pre class="smallexample"> (gdb) |
| -data-list-register-names |
| ^done,register-names=["r0","r1","r2","r3","r4","r5","r6","r7", |
| "r8","r9","r10","r11","r12","r13","r14","r15","r16","r17","r18", |
| "r19","r20","r21","r22","r23","r24","r25","r26","r27","r28","r29", |
| "r30","r31","f0","f1","f2","f3","f4","f5","f6","f7","f8","f9", |
| "f10","f11","f12","f13","f14","f15","f16","f17","f18","f19","f20", |
| "f21","f22","f23","f24","f25","f26","f27","f28","f29","f30","f31", |
| "", "pc","ps","cr","lr","ctr","xer"] |
| (gdb) |
| -data-list-register-names 1 2 3 |
| ^done,register-names=["r1","r2","r3"] |
| (gdb) |
| </pre> |
| <h4 class="subheading">The <code>-data-list-register-values</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002dlist_002dregister_002dvalues-3052"></a> |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-list-register-values |
| [ <code>--skip-unavailable</code> ] <var>fmt</var> [ ( <var>regno</var> )*] |
| </pre> |
| <p>Display the registers' contents. The format according to which the |
| registers' contents are to be returned is given by <var>fmt</var>, followed |
| by an optional list of numbers specifying the registers to display. A |
| missing list of numbers indicates that the contents of all the |
| registers must be returned. The <code>--skip-unavailable</code> option |
| indicates that only the available registers are to be returned. |
| |
| <p>Allowed formats for <var>fmt</var> are: |
| |
| <dl> |
| <dt><code>x</code><dd>Hexadecimal |
| <br><dt><code>o</code><dd>Octal |
| <br><dt><code>t</code><dd>Binary |
| <br><dt><code>d</code><dd>Decimal |
| <br><dt><code>r</code><dd>Raw |
| <br><dt><code>N</code><dd>Natural |
| </dl> |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p>The corresponding <span class="sc">gdb</span> commands are ‘<samp><span class="samp">info reg</span></samp>’, ‘<samp><span class="samp">info |
| all-reg</span></samp>’, and (in <code>gdbtk</code>) ‘<samp><span class="samp">gdb_fetch_registers</span></samp>’. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <p>For a PPC MBX board (note: line breaks are for readability only, they |
| don't appear in the actual output): |
| |
| <pre class="smallexample"> (gdb) |
| -data-list-register-values r 64 65 |
| ^done,register-values=[{number="64",value="0xfe00a300"}, |
| {number="65",value="0x00029002"}] |
| (gdb) |
| -data-list-register-values x |
| ^done,register-values=[{number="0",value="0xfe0043c8"}, |
| {number="1",value="0x3fff88"},{number="2",value="0xfffffffe"}, |
| {number="3",value="0x0"},{number="4",value="0xa"}, |
| {number="5",value="0x3fff68"},{number="6",value="0x3fff58"}, |
| {number="7",value="0xfe011e98"},{number="8",value="0x2"}, |
| {number="9",value="0xfa202820"},{number="10",value="0xfa202808"}, |
| {number="11",value="0x1"},{number="12",value="0x0"}, |
| {number="13",value="0x4544"},{number="14",value="0xffdfffff"}, |
| {number="15",value="0xffffffff"},{number="16",value="0xfffffeff"}, |
| {number="17",value="0xefffffed"},{number="18",value="0xfffffffe"}, |
| {number="19",value="0xffffffff"},{number="20",value="0xffffffff"}, |
| {number="21",value="0xffffffff"},{number="22",value="0xfffffff7"}, |
| {number="23",value="0xffffffff"},{number="24",value="0xffffffff"}, |
| {number="25",value="0xffffffff"},{number="26",value="0xfffffffb"}, |
| {number="27",value="0xffffffff"},{number="28",value="0xf7bfffff"}, |
| {number="29",value="0x0"},{number="30",value="0xfe010000"}, |
| {number="31",value="0x0"},{number="32",value="0x0"}, |
| {number="33",value="0x0"},{number="34",value="0x0"}, |
| {number="35",value="0x0"},{number="36",value="0x0"}, |
| {number="37",value="0x0"},{number="38",value="0x0"}, |
| {number="39",value="0x0"},{number="40",value="0x0"}, |
| {number="41",value="0x0"},{number="42",value="0x0"}, |
| {number="43",value="0x0"},{number="44",value="0x0"}, |
| {number="45",value="0x0"},{number="46",value="0x0"}, |
| {number="47",value="0x0"},{number="48",value="0x0"}, |
| {number="49",value="0x0"},{number="50",value="0x0"}, |
| {number="51",value="0x0"},{number="52",value="0x0"}, |
| {number="53",value="0x0"},{number="54",value="0x0"}, |
| {number="55",value="0x0"},{number="56",value="0x0"}, |
| {number="57",value="0x0"},{number="58",value="0x0"}, |
| {number="59",value="0x0"},{number="60",value="0x0"}, |
| {number="61",value="0x0"},{number="62",value="0x0"}, |
| {number="63",value="0x0"},{number="64",value="0xfe00a300"}, |
| {number="65",value="0x29002"},{number="66",value="0x202f04b5"}, |
| {number="67",value="0xfe0043b0"},{number="68",value="0xfe00b3e4"}, |
| {number="69",value="0x20002b03"}] |
| (gdb) |
| </pre> |
| <h4 class="subheading">The <code>-data-read-memory</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002dread_002dmemory-3053"></a> |
| This command is deprecated, use <code>-data-read-memory-bytes</code> instead. |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-read-memory [ -o <var>byte-offset</var> ] |
| <var>address</var> <var>word-format</var> <var>word-size</var> |
| <var>nr-rows</var> <var>nr-cols</var> [ <var>aschar</var> ] |
| </pre> |
| <p class="noindent">where: |
| |
| <dl> |
| <dt>‘<samp><var>address</var></samp>’<dd>An expression specifying the address of the first memory word to be |
| read. Complex expressions containing embedded white space should be |
| quoted using the C convention. |
| |
| <br><dt>‘<samp><var>word-format</var></samp>’<dd>The format to be used to print the memory words. The notation is the |
| same as for <span class="sc">gdb</span>'s <code>print</code> command (see <a href="Output-Formats.html#Output-Formats">Output Formats</a>). |
| |
| <br><dt>‘<samp><var>word-size</var></samp>’<dd>The size of each memory word in bytes. |
| |
| <br><dt>‘<samp><var>nr-rows</var></samp>’<dd>The number of rows in the output table. |
| |
| <br><dt>‘<samp><var>nr-cols</var></samp>’<dd>The number of columns in the output table. |
| |
| <br><dt>‘<samp><var>aschar</var></samp>’<dd>If present, indicates that each row should include an <span class="sc">ascii</span> dump. The |
| value of <var>aschar</var> is used as a padding character when a byte is not a |
| member of the printable <span class="sc">ascii</span> character set (printable <span class="sc">ascii</span> |
| characters are those whose code is between 32 and 126, inclusively). |
| |
| <br><dt>‘<samp><var>byte-offset</var></samp>’<dd>An offset to add to the <var>address</var> before fetching memory. |
| </dl> |
| |
| <p>This command displays memory contents as a table of <var>nr-rows</var> by |
| <var>nr-cols</var> words, each word being <var>word-size</var> bytes. In total, |
| <var>nr-rows</var><code> * </code><var>nr-cols</var><code> * </code><var>word-size</var> bytes are read |
| (returned as ‘<samp><span class="samp">total-bytes</span></samp>’). Should less than the requested number |
| of bytes be returned by the target, the missing words are identified |
| using ‘<samp><span class="samp">N/A</span></samp>’. The number of bytes read from the target is returned |
| in ‘<samp><span class="samp">nr-bytes</span></samp>’ and the starting address used to read memory in |
| ‘<samp><span class="samp">addr</span></samp>’. |
| |
| <p>The address of the next/previous row or page is available in |
| ‘<samp><span class="samp">next-row</span></samp>’ and ‘<samp><span class="samp">prev-row</span></samp>’, ‘<samp><span class="samp">next-page</span></samp>’ and |
| ‘<samp><span class="samp">prev-page</span></samp>’. |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p>The corresponding <span class="sc">gdb</span> command is ‘<samp><span class="samp">x</span></samp>’. <code>gdbtk</code> has |
| ‘<samp><span class="samp">gdb_get_mem</span></samp>’ memory read command. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <p>Read six bytes of memory starting at <code>bytes+6</code> but then offset by |
| <code>-6</code> bytes. Format as three rows of two columns. One byte per |
| word. Display each word in hex. |
| |
| <pre class="smallexample"> (gdb) |
| 9-data-read-memory -o -6 -- bytes+6 x 1 3 2 |
| 9^done,addr="0x00001390",nr-bytes="6",total-bytes="6", |
| next-row="0x00001396",prev-row="0x0000138e",next-page="0x00001396", |
| prev-page="0x0000138a",memory=[ |
| {addr="0x00001390",data=["0x00","0x01"]}, |
| {addr="0x00001392",data=["0x02","0x03"]}, |
| {addr="0x00001394",data=["0x04","0x05"]}] |
| (gdb) |
| </pre> |
| <p>Read two bytes of memory starting at address <code>shorts + 64</code> and |
| display as a single word formatted in decimal. |
| |
| <pre class="smallexample"> (gdb) |
| 5-data-read-memory shorts+64 d 2 1 1 |
| 5^done,addr="0x00001510",nr-bytes="2",total-bytes="2", |
| next-row="0x00001512",prev-row="0x0000150e", |
| next-page="0x00001512",prev-page="0x0000150e",memory=[ |
| {addr="0x00001510",data=["128"]}] |
| (gdb) |
| </pre> |
| <p>Read thirty two bytes of memory starting at <code>bytes+16</code> and format |
| as eight rows of four columns. Include a string encoding with ‘<samp><span class="samp">x</span></samp>’ |
| used as the non-printable character. |
| |
| <pre class="smallexample"> (gdb) |
| 4-data-read-memory bytes+16 x 1 8 4 x |
| 4^done,addr="0x000013a0",nr-bytes="32",total-bytes="32", |
| next-row="0x000013c0",prev-row="0x0000139c", |
| next-page="0x000013c0",prev-page="0x00001380",memory=[ |
| {addr="0x000013a0",data=["0x10","0x11","0x12","0x13"],ascii="xxxx"}, |
| {addr="0x000013a4",data=["0x14","0x15","0x16","0x17"],ascii="xxxx"}, |
| {addr="0x000013a8",data=["0x18","0x19","0x1a","0x1b"],ascii="xxxx"}, |
| {addr="0x000013ac",data=["0x1c","0x1d","0x1e","0x1f"],ascii="xxxx"}, |
| {addr="0x000013b0",data=["0x20","0x21","0x22","0x23"],ascii=" !\"#"}, |
| {addr="0x000013b4",data=["0x24","0x25","0x26","0x27"],ascii="$%&'"}, |
| {addr="0x000013b8",data=["0x28","0x29","0x2a","0x2b"],ascii="()*+"}, |
| {addr="0x000013bc",data=["0x2c","0x2d","0x2e","0x2f"],ascii=",-./"}] |
| (gdb) |
| </pre> |
| <h4 class="subheading">The <code>-data-read-memory-bytes</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002dread_002dmemory_002dbytes-3054"></a> |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-read-memory-bytes [ -o <var>offset</var> ] |
| <var>address</var> <var>count</var> |
| </pre> |
| <p class="noindent">where: |
| |
| <dl> |
| <dt>‘<samp><var>address</var></samp>’<dd>An expression specifying the address of the first addressable memory unit |
| to be read. Complex expressions containing embedded white space should be |
| quoted using the C convention. |
| |
| <br><dt>‘<samp><var>count</var></samp>’<dd>The number of addressable memory units to read. This should be an integer |
| literal. |
| |
| <br><dt>‘<samp><var>offset</var></samp>’<dd>The offset relative to <var>address</var> at which to start reading. This |
| should be an integer literal. This option is provided so that a frontend |
| is not required to first evaluate address and then perform address |
| arithmetics itself. |
| |
| </dl> |
| |
| <p>This command attempts to read all accessible memory regions in the |
| specified range. First, all regions marked as unreadable in the memory |
| map (if one is defined) will be skipped. See <a href="Memory-Region-Attributes.html#Memory-Region-Attributes">Memory Region Attributes</a>. Second, <span class="sc">gdb</span> will attempt to read the remaining |
| regions. For each one, if reading full region results in an errors, |
| <span class="sc">gdb</span> will try to read a subset of the region. |
| |
| <p>In general, every single memory unit in the region may be readable or not, |
| and the only way to read every readable unit is to try a read at |
| every address, which is not practical. Therefore, <span class="sc">gdb</span> will |
| attempt to read all accessible memory units at either beginning or the end |
| of the region, using a binary division scheme. This heuristic works |
| well for reading accross a memory map boundary. Note that if a region |
| has a readable range that is neither at the beginning or the end, |
| <span class="sc">gdb</span> will not read it. |
| |
| <p>The result record (see <a href="GDB_002fMI-Result-Records.html#GDB_002fMI-Result-Records">GDB/MI Result Records</a>) that is output of |
| the command includes a field named ‘<samp><span class="samp">memory</span></samp>’ whose content is a |
| list of tuples. Each tuple represent a successfully read memory block |
| and has the following fields: |
| |
| <dl> |
| <dt><code>begin</code><dd>The start address of the memory block, as hexadecimal literal. |
| |
| <br><dt><code>end</code><dd>The end address of the memory block, as hexadecimal literal. |
| |
| <br><dt><code>offset</code><dd>The offset of the memory block, as hexadecimal literal, relative to |
| the start address passed to <code>-data-read-memory-bytes</code>. |
| |
| <br><dt><code>contents</code><dd>The contents of the memory block, in hex. |
| |
| </dl> |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p>The corresponding <span class="sc">gdb</span> command is ‘<samp><span class="samp">x</span></samp>’. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <pre class="smallexample"> (gdb) |
| -data-read-memory-bytes &a 10 |
| ^done,memory=[{begin="0xbffff154",offset="0x00000000", |
| end="0xbffff15e", |
| contents="01000000020000000300"}] |
| (gdb) |
| </pre> |
| <h4 class="subheading">The <code>-data-write-memory-bytes</code> Command</h4> |
| |
| <p><a name="index-g_t_002ddata_002dwrite_002dmemory_002dbytes-3055"></a> |
| |
| <h5 class="subsubheading">Synopsis</h5> |
| |
| <pre class="smallexample"> -data-write-memory-bytes <var>address</var> <var>contents</var> |
| -data-write-memory-bytes <var>address</var> <var>contents</var> <span class="roman">[</span><var>count</var><span class="roman">]</span> |
| </pre> |
| <p class="noindent">where: |
| |
| <dl> |
| <dt>‘<samp><var>address</var></samp>’<dd>An expression specifying the address of the first addressable memory unit |
| to be written. Complex expressions containing embedded white space should |
| be quoted using the C convention. |
| |
| <br><dt>‘<samp><var>contents</var></samp>’<dd>The hex-encoded data to write. It is an error if <var>contents</var> does |
| not represent an integral number of addressable memory units. |
| |
| <br><dt>‘<samp><var>count</var></samp>’<dd>Optional argument indicating the number of addressable memory units to be |
| written. If <var>count</var> is greater than <var>contents</var>' length, |
| <span class="sc">gdb</span> will repeatedly write <var>contents</var> until it fills |
| <var>count</var> memory units. |
| |
| </dl> |
| |
| <h5 class="subsubheading"><span class="sc">gdb</span> Command</h5> |
| |
| <p>There's no corresponding <span class="sc">gdb</span> command. |
| |
| <h5 class="subsubheading">Example</h5> |
| |
| <pre class="smallexample"> (gdb) |
| -data-write-memory-bytes &a "aabbccdd" |
| ^done |
| (gdb) |
| </pre> |
| <pre class="smallexample"> (gdb) |
| -data-write-memory-bytes &a "aabbccdd" 16e |
| ^done |
| (gdb) |
| </pre> |
| <!-- %%%%%%%%%%%%%%%%%%%%%%%%%%%% SECTION %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% --> |
| </body></html> |
| |
