Class: GBRb::CPU::Ld

Inherits:
Instruction show all
Defined in:
lib/gbrb/cpu/instruction.rb

Direct Known Subclasses

Ldh

Instance Attribute Summary

Attributes inherited from Instruction

#i, #m, #t

Instance Method Summary collapse

Methods inherited from Instruction

#carry?, #immediate_count

Constructor Details

#initialize(destination, target, m = 1, t = 4, indirect_dest = false, indirect_target = false, immediates = 0, offset = 0x00) ⇒ Ld

Returns a new instance of Ld.



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# File 'lib/gbrb/cpu/instruction.rb', line 123

def initialize destination, target, m=1, t=4, indirect_dest=false, indirect_target=false, immediates=0, offset=0x00
  super m, t, immediates

  @destination = destination
  @target = target
  @indirect_dest = indirect_dest
  @indirect_target = indirect_target
  @offset = offset
end

Instance Method Details

#call(r, mem, v = nil) ⇒ Object 



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# File 'lib/gbrb/cpu/instruction.rb', line 133

def call r, mem, v=nil
  if not v
    v = r.public_send(@target.to_sym).read
  end

  if @indirect_target
    v = mem.read_byte(v + @offset)
    target_reg = r.public_send(@destination.to_sym)
    if @indirect_target == :increment
      target_reg.store target_reg.read + 1
    elsif @indirect_target == :decrement
      target_reg.store target_reg.read - 1
    end
  end


  if @indirect_dest
    if @indirect_dest == :immediate
      if @target.to_s.chars.length == 2
        mem.write_word(v + @offset, r.public_send(@target.to_sym).read)
      else
        mem.write_byte(v + @offset, r.public_send(@target.to_sym).read)
      end
    else
      reg = r.public_send(@destination.to_sym)
      mem.write_byte(reg.read + @offset, v)
      if @indirect_dest == :increment
        reg.store reg.read + 1
      elsif @indirect_dest == :decrement
        reg.store reg.read - 1
      end
    end
  else
    r.public_send(@destination.to_sym).store v
  end
end