67 lines
1.8 KiB
Ruby
67 lines
1.8 KiB
Ruby
module Arm
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# ADDRESSING MODE 4
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class StackInstruction < Register::Instruction
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include Constants
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include Attributed
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def initialize(first , attributes)
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super(nil)
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@attributes = attributes
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@first = first
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@attributes[:update_status] = 0 if @attributes[:update_status] == nil
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@attributes[:condition_code] = :al if @attributes[:condition_code] == nil
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@attributes[:opcode] = attributes[:opcode]
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@rn = :sp # sp register
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end
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# don't overwrite instance variables, to make assembly repeatable
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def assemble(io)
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operand = 0
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raise "invalid operand argument #{inspect}" unless (@first.is_a?(Array))
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@first.each do |r|
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raise "nil register in push, index #{r}- #{inspect}" if r.nil?
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operand = operand | (1 << reg_code(r))
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end
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val = operand
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val = val | (reg_code(@rn) << 16)
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val = val | (is_pop << 16 + 4) #20
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val = val | (1 << 16 + 4 + 1)
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val = val | (@attributes[:update_status] << 16 + 4 + 1 + 1)
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val = val | (up_down << 16 + 4 + 1 + 1 + 1)
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val = val | (pre_post_index << 16 + 4 + 1 + 1 + 1 + 1)#24
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val = val | instruction_code
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val = val | (cond << 16 + 4 + 1 + 1 + 1 + 1 + 2 + 2)
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io.write_unsigned_int_32 val
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end
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def cond
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if @attributes[:condition_code].is_a?(Symbol)
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COND_CODES[@attributes[:condition_code]]
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else
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@attributes[:condition_code]
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end
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end
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def instuction_class
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0b10 # OPC_STACK
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end
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def up_down
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(opcode == :push) ? 0 : 1
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end
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alias :is_pop :up_down
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def pre_post_index
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(opcode == :push) ? 1 : 0
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end
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def regs
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@first
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end
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def to_s
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"#{opcode} [#{@first.join(',') }] #{super}"
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end
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end
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end
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