86 lines
3.2 KiB
Ruby
86 lines
3.2 KiB
Ruby
module Arm
|
|
class LogicInstruction < Instruction
|
|
include Arm::Constants
|
|
# result = left op right
|
|
#
|
|
# Logic instruction are your basic operator implementation. But unlike the (normal) code we write
|
|
# these Instructions must have "place" to write their results. Ie when you write 4 + 5 in ruby
|
|
# the result is sort of up in the air, but with Instructions the result must be assigned
|
|
def initialize(result , left , right , attributes = {})
|
|
super(attributes)
|
|
@result = result
|
|
@left = left
|
|
@right = right.is_a?(Fixnum) ? Virtual::IntegerConstant.new(right) : right
|
|
@attributes[:update_status] = 0 if @attributes[:update_status] == nil
|
|
@attributes[:condition_code] = :al if @attributes[:condition_code] == nil
|
|
@operand = 0
|
|
|
|
raise "Left arg must be given #{inspect}" unless @left
|
|
@immediate = 0
|
|
end
|
|
|
|
attr_accessor :result , :left , :right
|
|
def assemble(io)
|
|
# don't overwrite instance variables, to make assembly repeatable
|
|
left = @left
|
|
operand = @operand
|
|
immediate = @immediate
|
|
|
|
right = @right
|
|
if @left.is_a?(Virtual::ObjectConstant)
|
|
# do pc relative addressing with the difference to the instuction
|
|
# 8 is for the funny pipeline adjustment (ie pointing to fetch and not execute)
|
|
right = @left.position - self.position - 8
|
|
left = :pc
|
|
end
|
|
# automatic wrapping, for machine internal code and testing
|
|
if( right.is_a? Fixnum )
|
|
right = Virtual::IntegerConstant.new( right )
|
|
end
|
|
if (right.is_a?(Virtual::IntegerConstant))
|
|
if (right.fits_u8?)
|
|
# no shifting needed
|
|
operand = right.integer
|
|
immediate = 1
|
|
elsif (op_with_rot = calculate_u8_with_rr(right))
|
|
operand = op_with_rot
|
|
immediate = 1
|
|
else
|
|
raise "cannot fit numeric literal argument in operand #{right.inspect}"
|
|
end
|
|
elsif (right.is_a?(Symbol) or right.is_a?(::Register::RegisterReference))
|
|
operand = reg_code(right) #integer means the register the integer is in (otherwise constant)
|
|
immediate = 0 # ie not immediate is register
|
|
else
|
|
raise "invalid operand argument #{right.inspect} , #{inspect}"
|
|
end
|
|
op = shift_handling
|
|
instuction_class = 0b00 # OPC_DATA_PROCESSING
|
|
val = shift(operand , 0)
|
|
val |= shift(op , 0) # any barral action, is already shifted
|
|
val |= shift(reg_code(@result) , 12)
|
|
val |= shift(reg_code(left) , 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 shift val , by
|
|
raise "Not integer #{val}:#{val.class} #{inspect}" unless val.is_a? Fixnum
|
|
val << by
|
|
end
|
|
|
|
def uses
|
|
ret = []
|
|
ret << @left.register if @left and not @left.is_a? Constant
|
|
ret << @right.register if @right and not @right.is_a?(Constant)
|
|
ret
|
|
end
|
|
def assigns
|
|
[@result.register]
|
|
end
|
|
end
|
|
end
|