Class: Gruesome::Z::Instruction

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

Overview

A Z-Machine instruction

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opcode, types, operands, destination, branch_destination, branch_condition, length) ⇒ Instruction

Returns a new instance of Instruction.



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# File 'lib/gruesome/z/instruction.rb', line 16

def initialize(opcode, types, operands, destination, branch_destination, branch_condition, length)
  @opcode = opcode
  @types = types
  @operands = operands
  @destination = destination
  @branch_to = branch_destination
  @branch_on = branch_condition
  @length = length
end

Instance Attribute Details

#branch_on ⇒ Object (readonly)

also… if 0, return true from routine

if 1, return false from routine



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# File 'lib/gruesome/z/instruction.rb', line 13

def branch_on
  @branch_on
end

#branch_to ⇒ Object (readonly)

the address to set the pc when branch is taken



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# File 'lib/gruesome/z/instruction.rb', line 10

def branch_to
  @branch_to
end

#destination ⇒ Object (readonly)

the destination variable to place the result



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# File 'lib/gruesome/z/instruction.rb', line 9

def destination
  @destination
end

#length ⇒ Object (readonly)

instruction size in number of bytes



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# File 'lib/gruesome/z/instruction.rb', line 14

def length
  @length
end

#opcode ⇒ Object (readonly)

the opcode



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# File 'lib/gruesome/z/instruction.rb', line 6

def opcode
  @opcode
end

#operands ⇒ Object (readonly)

the operands given to the instruction



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# File 'lib/gruesome/z/instruction.rb', line 8

def operands
  @operands
end

#types ⇒ Object (readonly)

the types of the operands



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# File 'lib/gruesome/z/instruction.rb', line 7

def types
  @types
end

Instance Method Details

#to_s(version) ⇒ Object 



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# File 'lib/gruesome/z/instruction.rb', line 26

def to_s(version)
  line = Opcode.name(@opcode, version)
  idx = -1
  line = line + @operands.inject("") do |result, element|
    idx += 1
    if @types[idx] == OperandType::VARIABLE
      result + " %" + sprintf("%02x", element)
    else
      result + " " + element.to_s
    end
  end

  if @destination != nil
    line = line + " -> %" + sprintf("%02x", @destination)
  end

  if @branch_to != nil
    line = line + " goto $" + sprintf("%04x", @branch_to) + " on " + @branch_on.to_s
  end

  line
end