Show current assembly instruction in GDB

Question

I m doing some assembly-level debugging in GDB  Is there a way to get GDB to show me the current assembly instruction in the same way that it shows the current source line  The default output after every command looks like this   0x0001433f      990         Foo  bar p     This gives me the address of the current instruction  but I have to keep referring back to the output of disassemble in order to see which instruction I m currently executing

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GDB Dashboard  https   github com cyrus-and gdb-dashboard  This GDB configuration uses the official GDB Python API to show us whatever we want whenever GDB stops after for example next  much like TUI   However I have found that this implementation is a more robust and configurable alternative to the built-in GDB TUI mode as explained at  gdb split view with code  For example  we can configure GDB Dashboard to show disassembly  source  registers and stack with   dashboard -layout source assembly registers stack   Here is what it looks like if you enable all available views instead     Related questions    Switching to assembly in gdb

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You can do  display i  pc   and every time GDB stops  it will display the disassembly of the next instruction   GDB-7 0 also supports set disassemble-next-line on  which will disassemble the entire next line  and give you more of the disassembly context

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From within gdb press Ctrl x 2 and the screen will split into 3 parts   First part will show you the normal code in high level language   Second will show you the assembly equivalent and corresponding instruction Pointer   Third will present you the normal gdb prompt to enter commands

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You can switch to assembly layout in GDB    gdb  layout asm   See here for more information  The current assembly instruction will be shown in assembler window       ---------------------------------------------------------------------------       0x7ffff740d756  lt   libc start main 214 gt   mov    0x39670b  rip   rax                 0x7ffff740d75d  lt   libc start main 221 gt   mov    0x8  rsp   rsi                      0x7ffff740d762  lt   libc start main 226 gt   mov    0x14  rsp   edi                     0x7ffff740d766  lt   libc start main 230 gt   mov      rax   rdx                         0x7ffff740d769  lt   libc start main 233 gt   callq   0x18  rsp                        gt   0x7ffff740d76d  lt   libc start main 237 gt   mov     eax  edi                           0x7ffff740d76f  lt   libc start main 239 gt   callq  0x7ffff7427970  lt exit gt                0x7ffff740d774  lt   libc start main 244 gt   xor     edx  edx                           0x7ffff740d776  lt   libc start main 246 gt   jmpq   0x7ffff740d6b9  lt   libc start        0x7ffff740d77b  lt   libc start main 251 gt   mov    0x39ca2e  rip   rax                 0x7ffff740d782  lt   libc start main 258 gt   ror     0x11  rax                          0x7ffff740d786  lt   libc start main 262 gt   xor     fs 0x30  rax                       0x7ffff740d78f  lt   libc start main 271 gt   callq    rax                              ---------------------------------------------------------------------------  multi-thre process 3718 In    libc start main     Line       PC  0x7ffff740d76d  3  0x00007ffff7466eb5 in  IO do write    from  lib x86 64-linux-gnu libc so 6  4  0x00007ffff74671ff in  IO file overflow       from  lib x86 64-linux-gnu libc so 6  5  0x0000000000408756 in        6  0x0000000000403980 in        7  0x00007ffff740d76d in   libc start main       from  lib x86 64-linux-gnu libc so 6  gdb

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There is a simple solution that consists in using stepi  which in turns moves forward by 1 asm instruction and shows the surrounding asm code

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If you want the next few instructions to display automatically while stepping through the program you can use the display command as follows -   display  3i  pc  The above will display 3 instructions whenever a breakpoint is hit or when you single step the program   More details at the blog entry here

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The command   x i  pc   can be set to run all the time using the usual configuration mechanism

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Setting the following option   set  disassemble-next-line on show disassemble-next-line   Will give you results that look like this    gdb  stepi 0x000002ce in ResetISR    at startup gcc c 245 245      0x000002cc  lt ResetISR 0 gt   80 b5   push     r7  lr    gt  0x000002ce  lt ResetISR 2 gt   82 b0   sub sp   8    0x000002d0  lt ResetISR 4 gt   00 af   add r7  sp   0  gdb  stepi 0x000002d0  245      0x000002cc  lt ResetISR 0 gt   80 b5   push     r7  lr     0x000002ce  lt ResetISR 2 gt   82 b0   sub sp   8   gt  0x000002d0  lt ResetISR 4 gt   00 af   add r7  sp   0

[assembly] Show current assembly instruction in GDB

Examples related to assembly

Examples related to gdb