96 lines
3.1 KiB
Ruby
96 lines
3.1 KiB
Ruby
|
module Arm
|
||
|
|
class CompareInstruction < Register::Instruction
|
||
|
|
include Constants
|
||
|
|
include Attributed
|
||
|
|
|
||
|
|
def initialize(left , right , attributes)
|
||
|
|
super(nil)
|
||
|
|
@attributes = attributes
|
||
|
|
@left = left
|
||
|
|
@right = right.is_a?(Fixnum) ? IntegerConstant.new(right) : right
|
||
|
|
@attributes[:condition_code] = :al if @attributes[:condition_code] == nil
|
||
|
|
@operand = 0
|
||
|
|
@immediate = 0
|
||
|
|
@attributes[:update_status] = 1
|
||
|
|
@rn = left
|
||
|
|
@rd = :r0
|
||
|
|
end
|
||
|
|
|
||
|
|
def assemble(io)
|
||
|
|
# don't overwrite instance variables, to make assembly repeatable
|
||
|
|
rn = @rn
|
||
|
|
operand = @operand
|
||
|
|
immediate = @immediate
|
||
|
|
|
||
|
|
arg = @right
|
||
|
|
if arg.is_a?(Parfait::Object)
|
||
|
|
# do pc relative addressing with the difference to the instuction
|
||
|
|
# 8 is for the funny pipeline adjustment (ie oc pointing to fetch and not execute)
|
||
|
|
arg = arg.position - self.position - 8
|
||
|
|
rn = :pc
|
||
|
|
end
|
||
|
|
if( arg.is_a? Symbol )
|
||
|
|
arg = Register::RegisterValue.new( arg , :Integer)
|
||
|
|
end
|
||
|
|
if (arg.is_a?(Numeric))
|
||
|
|
if (arg.fits_u8?)
|
||
|
|
# no shifting needed
|
||
|
|
operand = arg
|
||
|
|
immediate = 1
|
||
|
|
elsif (op_with_rot = calculate_u8_with_rr(arg))
|
||
|
|
operand = op_with_rot
|
||
|
|
immediate = 1
|
||
|
|
raise "hmm"
|
||
|
|
else
|
||
|
|
raise "cannot fit numeric literal argument in operand #{arg.inspect}"
|
||
|
|
end
|
||
|
|
elsif (arg.is_a?(Symbol) or arg.is_a?(::Register::RegisterValue))
|
||
|
|
operand = arg
|
||
|
|
immediate = 0
|
||
|
|
elsif (arg.is_a?(Arm::Shift))
|
||
|
|
rm_ref = arg.argument
|
||
|
|
immediate = 0
|
||
|
|
shift_op = {'lsl' => 0b000, 'lsr' => 0b010, 'asr' => 0b100,
|
||
|
|
'ror' => 0b110, 'rrx' => 0b110}[arg.type]
|
||
|
|
if (arg.type == 'ror' and arg.value.nil?)
|
||
|
|
# ror #0 == rrx
|
||
|
|
raise "cannot rotate by zero #{arg} #{inspect}"
|
||
|
|
end
|
||
|
|
|
||
|
|
arg1 = arg.value
|
||
|
|
if (arg1.is_a?(Register::IntegerConstant))
|
||
|
|
if (arg1.value >= 32)
|
||
|
|
raise "cannot shift by more than 31 #{arg1} #{inspect}"
|
||
|
|
end
|
||
|
|
shift_imm = arg1.value
|
||
|
|
elsif (arg1.is_a?(Arm::Register))
|
||
|
|
shift_op val |= 0x1;
|
||
|
|
shift_imm = arg1.number << 1
|
||
|
|
elsif (arg.type == 'rrx')
|
||
|
|
shift_imm = 0
|
||
|
|
end
|
||
|
|
operand = rm_ref | (shift_op << 4) | (shift_imm << 4+3)
|
||
|
|
else
|
||
|
|
raise "invalid operand argument #{arg.inspect} , #{inspect}"
|
||
|
|
end
|
||
|
|
instuction_class = 0b00 # OPC_DATA_PROCESSING
|
||
|
|
val = (operand.is_a?(Symbol) or operand.is_a?(::Register::RegisterValue)) ? reg_code(operand) : operand
|
||
|
|
val = 0 if val == nil
|
||
|
|
val = shift(val , 0)
|
||
|
|
raise inspect unless reg_code(@rd)
|
||
|
|
val |= shift(reg_code(@rd) , 12)
|
||
|
|
val |= shift(reg_code(rn) , 12+4)
|
||
|
|
val |= shift(@attributes[:update_status] , 12+4+4)#20
|
||
|
|
val |= shift(op_bit_code , 12+4+4 +1)
|
||
|
|
val |= shift(immediate , 12+4+4 +1+4)
|
||
|
|
val |= shift(instuction_class , 12+4+4 +1+4+1)
|
||
|
|
val |= shift(cond_bit_code , 12+4+4 +1+4+1+2)
|
||
|
|
io.write_uint32 val
|
||
|
|
end
|
||
|
|
|
||
|
|
def to_s
|
||
|
|
"#{opcode} #{@left} , #{@right} #{super}"
|
||
|
|
end
|
||
|
|
end
|
||
|
|
end
|