How To Print The Address Of A Register In Gdb

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info registers shows all the registers; info registers eax shows just the register eax. The command can be abbreviated equally i r

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If you're trying to print a specific register in GDB, y'all have to omit the % sign. For instance,

              info registers eip

If your executable is 64 bit, the registers start with r. Starting them with east is not valid.

              info registers rip

Those can be abbreviated to:

              i r rip

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In that location is too:

              info all-registers

Then you tin can get the register proper noun you are interested in -- very useful for finding platform-specific registers (like NEON Q... on ARM).

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If simply want check it once, info registers show registers.
If simply want watch 1 register, for example, brandish $esp continue display esp registers in gdb command line.
If want sentinel all registers, layout regs continue show registers, with TUI fashion.

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Gdb commands:

i r <register_name>: print a unmarried register, due east.yard i r rax, i r eax
i r <register_name_1> <register_name_2> ...: print multiple registers, e.g i r rdi rsi,
i r: impress all register except floating bespeak & vector register (xmm, ymm, zmm).
i r a: impress all register, include floating point & vector register (xmm, ymm, zmm).
i r f: impress all FPU floating registers (st0-7 and a few other f*)

Other register groups besides a (all) and f (float) tin can exist constitute with:

              maint print reggroups

as documented at: https://sourceware.org/gdb/electric current/onlinedocs/gdb/Registers.html#Registers

Tips:

xmm0 ~ xmm15, are 128 bits, near every modern motorcar has it, they are released in 1999.
ymm0 ~ ymm15, are 256 bits, new machine normally accept it, they are released in 2011.
zmm0 ~ zmm31, are 512 bits, normal pc probably don't have it (as the yr 2016), they are released in 2013, and mainly used in servers then far.
Merely one serial of xmm / ymm / zmm will be shown, because they are the same registers in different style. On my machine ymm is shown.