Class: GBRb::InstructionSet::Inc

Inherits:
Instruction show all
Defined in:
lib/gbrb/instruction_set/arithmetic.rb

Instance Attribute Summary

Attributes inherited from Instruction

#i, #m, #t

Instance Method Summary collapse

Methods inherited from Instruction

#carry?, #immediate_count

Constructor Details

#initialize(register, m = 1, t = 4, flags = true, indirect = false) ⇒ Inc

Returns a new instance of Inc.



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# File 'lib/gbrb/instruction_set/arithmetic.rb', line 160

def initialize register, m=1, t=4, flags=true, indirect=false
  super m, t

  @register = register
  @flags = flags
  @op = :+
  @indirect = indirect
end

Instance Method Details

#call(r, mem) ⇒ Object 



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# File 'lib/gbrb/instruction_set/arithmetic.rb', line 169

def call r, mem
  reg = r.public_send(@register.to_sym)
  tmp = reg.read
  if @indirect
    v = mem.read_byte(tmp) + 1
    mem.write_byte(tmp, v)
    tmp = v
    reg = r.h
  else
    reg.store tmp + 1
  end
  if @flags
    r.clear_add_sub_flag
    if @indirect
      (tmp & 0xff == 0x00) ? r.set_zero_flag : r.clear_zero_flag
      if carry? tmp - 1, 0x01, r.h.half_mask
        r.set_half_carry_flag
      else
        r.clear_half_carry_flag
      end
    else
      reg.zero? ? r.set_zero_flag : r.clear_zero_flag
      if carry? tmp, 0x01, reg.half_mask
        r.set_half_carry_flag
      else
        r.clear_half_carry_flag
      end
    end
  end
end