Module: YTLJit::AssemblerUtilIAModrm

Included in:
AssemblerUtilIA
Defined in:
lib/ytljit/instruction_ia.rb

Instance Method Summary collapse

Instance Method Details

#modrm(inst, reg, rm, dst, src, src2 = nil) ⇒ Object 



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# File 'lib/ytljit/instruction_ia.rb', line 531

def modrm(inst, reg, rm, dst, src, src2 = nil)
  case reg
  when Integer
    case rm
    when OpRegistor
      [[0b11000000 | ((reg & 7) << 3) | (rm.reg_no & 7)], "C"]

    when OpIndirect
      modrm_indirect(reg, rm)

    when Integer, OpImmidiate
      [[0b00000000 | ((reg & 7) << 3) | 5], "C"]

    else
      return nosupported_addressing_mode(inst, dst, src, src2)
    end

  when OpRegistor
    case rm
    when OpRegistor
      [[0b11000000 | ((reg.reg_no & 7) << 3) | (rm.reg_no & 7)], "C"]

    when OpIndirect
      modrm_indirect(reg, rm)
    end

  else
    return nosupported_addressing_mode(inst, dst, src, src2)
  end
end

#modrm_indirect(reg, rm) ⇒ Object 



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# File 'lib/ytljit/instruction_ia.rb', line 486

def modrm_indirect(reg, rm)
  regv = nil
  case reg
  when Integer
    regv = reg
    
  else
    regv = reg.value
  end

  rmdisp = rm.disp
  if rmdisp.class == OpImmidiate then
    rmdisp = rmdisp.value
  end

  case rmdisp
  when 0
    if rm.reg.is_a?(OpEBP) or 
        rm.reg.is_a?(OpRBP) or rm.reg.is_a?(OpR13) then
      modrm_indirect_off8(regv, rm.reg, 0)
    else
      fstb = 0b00000000 | ((regv & 7) << 3) | (rm.reg.reg_no & 7)
      if rm.reg.is_a?(OpESP) or 
          rm.reg.is_a?(OpRSP) or rm.reg.is_a?(OpR12) then
        [[fstb, 0x24], "C2"]
      else
        [[fstb], "C"]
      end
    end
    
  when OpImmidiate8
    modrm_indirect_off8(regv, rm.reg, rmdisp.value)
    
  when OpImmidiate32
    modrm_indirect_off32(regv, rm.reg, rmdisp.value)

  when Integer
    if small_integer_8bit?(rmdisp.abs) then
      modrm_indirect_off8(regv, rm.reg, rmdisp)
    else
      modrm_indirect_off32(regv, rm.reg, rmdisp)
    end
  end
end

#modrm_indirect_off32(regv, rm_reg, rm_disp) ⇒ Object 



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# File 'lib/ytljit/instruction_ia.rb', line 466

def modrm_indirect_off32(regv, rm_reg, rm_disp)
  fstb = 0b10000000 | ((regv & 7) << 3) | (rm_reg.reg_no & 7)
  if rm_reg.is_a?(OpESP) or 
      rm_reg.is_a?(OpRSP) or rm_reg.is_a?(OpR12) then
    [[fstb, 0b00100100, rm_disp], "C2L"]
  else
    [[fstb, rm_disp], "CL"]
  end
end

#modrm_indirect_off8(regv, rm_reg, rm_disp) ⇒ Object 



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# File 'lib/ytljit/instruction_ia.rb', line 476

def modrm_indirect_off8(regv, rm_reg, rm_disp)
  fstb = 0b01000000 | ((regv & 7) << 3) | (rm_reg.reg_no & 7)
  if rm_reg.is_a?(OpESP) or 
      rm_reg.is_a?(OpRSP) or rm_reg.is_a?(OpR12) then
    [[fstb, 0b00100100, rm_disp], "C3"]
  else
    [[fstb, rm_disp], "CC"]
  end
end

#small_integer_32bit?(num) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ytljit/instruction_ia.rb', line 461

def small_integer_32bit?(num)
  num = (num & 0x7fff_ffff_ffff_ffff) - (num & 0x8000_0000_0000_0000)
  num.abs < 0x7fff_ffff
end

#small_integer_8bit?(num) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ytljit/instruction_ia.rb', line 456

def small_integer_8bit?(num)
  num = (num & 0x7fff_ffff) - (num & 0x8000_0000)
  num.abs < 0x7f
end