46 lines
1.5 KiB
Ruby
46 lines
1.5 KiB
Ruby
module Risc
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# Getter is a base class for get instructions (SlotToReg and ByteToReg , possibly more coming)
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#
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# The instruction that is modelled is loading data from an array into a register
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#
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# Getter has a
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# - an array where the data comes from
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# - an (array) index
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# - Register that the data is moved to
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# Getter and Setter api follow the pattern from -> to
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class Getter < Instruction
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# If you had a c array and index offset
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# the instruction would do register = array[index]
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# The arguments are in the order that makes sense for the Instruction name
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# So SlotToReg means the slot (array and index) moves to the register (last argument)
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def initialize( source , array , index , register )
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super(source)
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@array = array
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@index = index
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@register = register
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raise "index #{index}" if index.is_a?(Numeric) and index < 0
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raise "Not integer or reg #{index}" unless index.is_a?(Numeric) or RegisterValue.look_like_reg(index)
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raise "Not register #{register}" unless RegisterValue.look_like_reg(register)
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raise "Not register #{array}" unless RegisterValue.look_like_reg(array)
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end
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attr_accessor :array , :index , :register
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# return an array of names of registers that is used by the instruction
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def register_names
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names = [array.symbol , register.symbol]
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names << index.symbol if index.is_a?(RegisterValue)
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names
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end
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def to_s
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class_source "#{array}[#{index}] -> #{register}"
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end
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end
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end
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