# -*- coding: binary -*-

module Rex
module Arch

#
# Everything here is mostly stolen from vlad's perl sparc stuff
#
module Sparc

  #
  # Register number constants
  #
  RegisterNumber =
    {
      'g0' =>  0, 'g1' =>  1, 'g2' =>  2, 'g3' =>  3,
      'g4' =>  4, 'g5' =>  5, 'g6' =>  6, 'g7' =>  7,
      'o0' =>  8, 'o1' =>  9, 'o2' => 10, 'o3' => 11,
      'o4' => 12, 'o5' => 13, 'o6' => 14, 'o7' => 15,
      'l0' => 16, 'l1' => 17, 'l2' => 18, 'l3' => 19,
      'l4' => 20, 'l5' => 21, 'l6' => 22, 'l7' => 23,
      'i0' => 24, 'i1' => 25, 'i2' => 26, 'i3' => 27,
      'i4' => 28, 'i5' => 29, 'i6' => 30, 'i7' => 31,
      'sp' => 14, 'fp' => 30,
    } # :nodoc:

  #
  # Encodes a SETHI instruction with the value 'constant' being put into 'dst' register
  #
  def self.sethi(constant, dst)
    [
      (RegisterNumber[dst] << 25) |
      (4 << 22) |
      (constant >> 10)
    ].pack('N')
  end

  #
  # Encodes an OR instruction with the value 'constant' being OR'ed with the 'src' register into the 'dst' register
  #
  def self.ori(src, constant, dst)
    [
      (2 << 30) |
      (RegisterNumber[dst] << 25) |
      (2 << 19) |
      (RegisterNumber[src] << 14) |
      (1 << 13) |
      (constant & 0x1fff)
    ].pack('N')
  end

  #
  # Puts 'constant' into the 'dst' register using as few instructions as possible by checking the size of the value.
  # XXX: signedness support
  #
  def self.set(constant, dst)
    if (constant <= 4095 and constant >= 0)
      ori('g0', constant, dst)
    elsif (constant & 0x3ff != 0)
      set_dword(constant, dst)
    else
      sethi(constant, dst)
    end
  end

  #
  # Puts 'constant' into the 'dst' register using both sethi and ori (necessary to use both uncessarily in some cases with encoders)
  #
  def self.set_dword(constant, dst)
    sethi(constant, dst) + ori(dst, constant & 0x3ff, dst)
  end

end

end end
