Class: Evoasm::X64::Instruction

Inherits:
FFI::Pointer show all
Defined in:
lib/evoasm/x64/instruction.rb

Overview

Represents an x86-64 instruction

Defined Under Namespace

Classes: Parameter

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods inherited from FFI::Pointer

#to_ptr

Instance Attribute Details

#name ⇒ Symbol (readonly)

Returns the instruction's name

Returns:

  • (Symbol) —

    the instruction's name



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# File 'lib/evoasm/x64/instruction.rb', line 16

def name
  @name
end

Instance Method Details

#basic? ⇒ Bool

Returns whether this instruction is encodable with the basic encoder

Returns:

  • (Bool) 


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# File 'lib/evoasm/x64/instruction.rb', line 63

def basic?
  Libevoasm.x64_inst_is_basic(self)
end

#encode(parameters, buffer = nil, basic: false) ⇒ void

This method returns an undefined value.

Encodes the instruciton with the given parameters

Parameters:

  • parameters (X64::Parameters) —

    parameters

  • buffer (Buffer) (defaults to: nil) —

    the buffer to emit to

  • basic (Bool) —

    whether the basic encoder should be used



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# File 'lib/evoasm/x64/instruction.rb', line 72

def encode(parameters, buffer = nil, basic: false)
  if basic && !basic?
    raise ArgumentError, 'instruction does not support basic mode'
  end

  buf_ref = Libevoasm.buf_ref_alloc

  if buffer
    Libevoasm.buf_to_buf_ref buffer, buf_ref
  else
    data = FFI::MemoryPointer.new :uint8, 32
    len_ptr = FFI::MemoryPointer.new :size_t, 1
    Libevoasm.buf_ref_init buf_ref, data, len_ptr
  end

  parameters = Parameters.for(parameters, basic: basic)

  success =
    if basic
      Libevoasm.x64_inst_enc_basic self, parameters, buf_ref
    else
      Libevoasm.x64_inst_enc self, parameters, buf_ref
    end

  Libevoasm.buf_ref_free buf_ref

  if success
    unless buffer
      len = len_ptr.read_size_t
      data.read_string len
    end
  else
    raise Error.last
  end
end

#mnemonic ⇒ String

Gives the preferred instruction mnemonic

Returns:

  • (String) —

    the mnemonics

See Also:



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# File 'lib/evoasm/x64/instruction.rb', line 33

def mnemonic
  mnemonics.first
end

#mnemonics ⇒ Array<String>

Gives a list of instruction mnemonics

Returns:

  • (Array<String>) —

    mnemonics



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# File 'lib/evoasm/x64/instruction.rb', line 26

def mnemonics
  Libevoasm.x64_inst_get_mnem(self).split('/')
end

#operand(index) ⇒ Operand

Gives the operand at the specified index

Returns:



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# File 'lib/evoasm/x64/instruction.rb', line 39

def operand(index)
  Operand.new Libevoasm.x64_inst_get_operand(self, index), self
end

#operands ⇒ Array<Operand>

Gives the instruction's operands

Returns:

  • (Array<Operand>) —

    the operands



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# File 'lib/evoasm/x64/instruction.rb', line 45

def operands
  n_operands = Libevoasm.x64_inst_get_n_operands self
  Array.new(n_operands) do |index|
    operand index
  end
end

#parameters ⇒ Array<Instruction::Parameter>

Gives this instruction's parameters

Returns:



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# File 'lib/evoasm/x64/instruction.rb', line 54

def parameters
  n_params = Libevoasm.x64_inst_get_n_params self
  Array.new(n_params) do |param_index|
    Parameter.new Libevoasm.x64_inst_get_param(self, param_index)
  end
end