c - GDB single stepping assembly and displaying the next instruction which will be executed. -


this question has answer here:

using gdb debbuger command can execute single step , display next instruction executed? i'm familiar windbg operation pretty straight forward.

so example have following function , step code via si want display next instruction executed without having full disassembly via disassemble. how can accomplish this? 

dump of assembler code function iseven:    0x0000000100000f20 <+0>: push   %rbp    0x0000000100000f21 <+1>: mov    %rsp,%rbp    0x0000000100000f24 <+4>: mov    $0x2,%eax    0x0000000100000f29 <+9>: mov    %edi,-0x4(%rbp) => 0x0000000100000f2c <+12>:    mov    -0x4(%rbp),%edi    0x0000000100000f2f <+15>:    mov    %eax,-0xc(%rbp)    0x0000000100000f32 <+18>:    mov    %edi,%eax    0x0000000100000f34 <+20>:    cltd    0x0000000100000f35 <+21>:    mov    -0xc(%rbp),%edi    0x0000000100000f38 <+24>:    idiv   %edi    0x0000000100000f3a <+26>:    cmp    $0x0,%edx    0x0000000100000f3d <+29>:    jne    0x100000f4f <iseven+47>    0x0000000100000f43 <+35>:    movl   $0x1,-0x8(%rbp)    0x0000000100000f4a <+42>:    jmpq   0x100000f56 <iseven+54>    0x0000000100000f4f <+47>:    movl   $0x0,-0x8(%rbp)    0x0000000100000f56 <+54>:    mov    -0x8(%rbp),%eax    0x0000000100000f59 <+57>:    pop    %rbp    0x0000000100000f5a <+58>:    retq end of assembler dump. (gdb)

i found following sequence of instructions accomplishes objective.

(gdb) show disassemble-next-line debugger's willingness use disassemble-next-line off. (gdb) set disassemble-next-line on (gdb) show disassemble-next-line debugger's willingness use disassemble-next-line on.

thanks olaf!

(gdb) si 0x0000000100000f32  27      if(num % 2 == 0 )    0x0000000100000f2c <iseven+12>:  8b 7d fc    mov    -0x4(%rbp),%edi    0x0000000100000f2f <iseven+15>:  89 45 f4    mov    %eax,-0xc(%rbp) => 0x0000000100000f32 <iseven+18>:  89 f8   mov    %edi,%eax    0x0000000100000f34 <iseven+20>:  99  cltd    0x0000000100000f35 <iseven+21>:  8b 7d f4    mov    -0xc(%rbp),%edi    0x0000000100000f38 <iseven+24>:  f7 ff   idiv   %edi    0x0000000100000f3a <iseven+26>:  83 fa 00    cmp    $0x0,%edx    0x0000000100000f3d <iseven+29>:  0f 85 0c 00 00 00   jne    0x100000f4f <iseven+47>

-

Comments

Post a Comment

Popular posts from this blog

java - SSE Emitter : Manage timeouts and complete() -

i writing web app multiple listeners(evcentsource sse clients js) connected server . want store sse emitter per connected listener : can done in memory or other means assigning id each client able achieve far now question ; how send response/event specific client connected web app ? while doing sseemmiters stored either getting completed or timed out. how prevent ? how keep sseemmiter available open infinite time (till client closes) , send events selectively .
Read more

jquery - uncaught exception: DataTables Editor - remote hosting of code not allowed -

i'm trying implement crud operation using datatableseditor using datatables.but i'm getting error messages: 1)uncaught exception: datatables editor - remote hosting of code not allowed. please see http://editor.datatables.net details on how purchase editor license 2)typeerror: a.editor undefined 3) $.fn.datatable.editor not constructor" what reason? here configuration: <%@ page language="java" contenttype="text/html; charset=iso-8859-1" pageencoding="iso-8859-1"%> <!doctype html public "-//w3c//dtd html 4.01 transitional//en" "http://www.w3.org/tr/html4/loose.dtd"> <html> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1"> <title>insert title here</title> <link rel="stylesheet" type="text/css" href="//cdn.datatables.net/1.10.12/css/jquery.datatables.min.css"> <link re...
Read more

java - How to resolve error - package com.squareup.okhttp3 doesn't exist? -

i trying convert json java object use of gson in maven, following youtube video guidance - https://www.youtube.com/watch?v=vqgghm9pwe0 , theres error occurs when in main class error - package com.squareup.okhttp3 doesn't exist. code below: java package com.codebeasty.json; import com.squareup.okhttp3.okhttpclient; public class main { private static okhttpclient client = new okhttpclient(); public static void main (string [] args) { } } i put in dependency in pom.xml: <dependencies> <dependency> <groupid>com.squareup.okhttp3</groupid> <artifactid>okhttp</artifactid> <version>3.4.2</version> </dependency> <dependency> <groupid>com.google.code.gson</groupid> <artifactid>gson</artifactid> <version>2.8.0</version> </dependency> </dependencies> i dont understand why doesn't recognize com.squareup. there may need download? have downl...
Read more