Class: Instruction::Encoding

Inherits:
Object
  • Object
show all
Defined in:
lib/arch_obj_models/instruction.rb

Overview

represents an instruction encoding

Defined Under Namespace

Classes: Field

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(format, decode_vars) ⇒ Encoding

Returns a new instance of Encoding.

Parameters:

  • format (String) —

    Format of the encoding, as 0’s, 1’s and -‘s (for decode variables)

  • decode_vars (Array<Hash<String,Object>>) —

    List of decode variable defintions from the arch spec



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# File 'lib/arch_obj_models/instruction.rb', line 519

def initialize(format, decode_vars)
  @format = format

  @opcode_fields = []
  field_chars = []
  @format.chars.each_with_index do |c, idx|
    if c == "-"
      next if field_chars.empty?

      field_text = field_chars.join("")
      field_lsb = @format.size - idx
      field_msb = @format.size - idx - 1 + field_text.size
      @opcode_fields << Field.new(field_text, field_lsb..field_msb)

      field_chars.clear
      next
    else
      field_chars << c
    end
  end

  # add the least significant field
  unless field_chars.empty?
    field_text = field_chars.join("")
    @opcode_fields << Field.new(field_text, 0...field_text.size)
  end

  @decode_variables = []
  decode_vars&.each do |var|
    @decode_variables << DecodeVariable.new(self, var)
  end
end

Instance Attribute Details

#decode_variables ⇒ Array<DecodeVariable> (readonly)

Returns List of decode variables.

Returns:



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# File 'lib/arch_obj_models/instruction.rb', line 486

def decode_variables
  @decode_variables
end

#format ⇒ String (readonly)

Returns format, as a string of 0,1 and -,.

Examples:

Format of ‘sd`

sd.format #=> '-----------------011-----0100011'

Returns:

  • (String) —

    format, as a string of 0,1 and -,



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# File 'lib/arch_obj_models/instruction.rb', line 478

def format
  @format
end

#opcode_fields ⇒ Array<Field> (readonly)

Returns List of fields containing opcodes.

Examples:

opcode_fields of ‘sd`

sd.opcode_fields #=> [Field('011', ...), Field('0100011', ...)]

Returns:

  • (Array<Field>) —

    List of fields containing opcodes



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# File 'lib/arch_obj_models/instruction.rb', line 483

def opcode_fields
  @opcode_fields
end

Instance Method Details

#size ⇒ Integer

Returns Size, in bits, of the encoding.

Returns:

  • (Integer) —

    Size, in bits, of the encoding



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# File 'lib/arch_obj_models/instruction.rb', line 553

def size
  @format.size
end