How To Print Register Value In Gdb

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info registers shows all the registers; info registers eax shows just the annals eax. The command tin can be abbreviated as i r

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If you're trying to impress a specific annals in GDB, you take to omit the % sign. For instance,

              info registers eip

If your executable is 64 bit, the registers starting time with r. Starting them with e is not valid.

              info registers rip

Those can be abbreviated to:

              i r rip

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At that place is also:

              info all-registers

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

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If only desire check it once, info registers bear witness registers.
If only desire watch ane register, for instance, brandish $esp continue brandish esp registers in gdb control line.
If want sentry all registers, layout regs continue prove registers, with TUI mode.

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Gdb commands:

i r <register_name>: print a single annals, e.thousand i r rax, i r eax
i r <register_name_1> <register_name_2> ...: impress multiple registers, e.thou i r rdi rsi,
i r: print all annals except floating point & vector register (xmm, ymm, zmm).
i r a: print all register, include floating bespeak & vector annals (xmm, ymm, zmm).
i r f: print all FPU floating registers (st0-vii and a few other f*)

Other annals groups besides a (all) and f (float) tin can exist plant with:

              maint print reggroups

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

Tips:

xmm0 ~ xmm15, are 128 bits, almost every modern auto has it, they are released in 1999.
ymm0 ~ ymm15, are 256 bits, new automobile normally have it, they are released in 2011.
zmm0 ~ zmm31, are 512 bits, normal pc probably don't have it (as the year 2016), they are released in 2013, and mainly used in servers so far.
Only ane serial of xmm / ymm / zmm volition be shown, considering they are the same registers in different mode. On my machine ymm is shown.

How To Print Register Value In Gdb,

Source: https://thecodeteacher.com/question/16388/How-to-print-register-values-in-GDB