41 lines
1.4 KiB
Ruby
41 lines
1.4 KiB
Ruby
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module Register
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# GetByte moves a single byte into a register from memory.
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# indexes are 1 based (as for slots) , which means we sacrifice a byte of every word
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# for our sanity
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class GetByte < Instruction
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# If you had a c array (of int8) 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 GetSlot 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 0 " if 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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def to_s
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"GetByte: #{array}[#{index}] -> #{register}"
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end
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end
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# Produce a GetByte instruction.
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# from and to are translated (from symbol to register if neccessary)
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# but index is left as is.
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def self.get_byte source , array , index , to
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from = resolve_to_register from
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to = resolve_to_register to
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GetByte.new( source , array , index , to)
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end
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end
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