78 lines
1.9 KiB
Ruby
78 lines
1.9 KiB
Ruby
require_relative "values"
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module Vm
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# Think flowcharts: blocks are the boxes. The smallest unit of linear code
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# Blocks must end in control instructions (jump/call/return).
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# And the only valid argument for a jump is a Block
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# Blocks form a linked list
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# There are four ways for a block to get data (to work on)
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# - hard coded constants (embedded in code)
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# - memory move
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# - values passed in (from previous blocks. ie local variables)
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# See Value description on how to create code/instructions
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# Codes then get assembled into bytes (after linking)
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class Block < Code
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def initialize(name)
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super()
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@name = name.to_sym
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@next = nil
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@codes = []
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end
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attr_reader :name , :next , :codes
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def length
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@codes.inject(0) {| sum , item | sum + item.length}
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end
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def add_code(kode)
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raise "alarm #{kode}" if kode.is_a? Word
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raise "alarm #{kode}" unless kode.is_a? Code
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@codes << kode
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self
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end
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def link_at pos , context
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@position = pos
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@codes.each do |code|
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code.link_at(pos , context)
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pos += code.length
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end
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pos
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end
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def assemble(io)
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@codes.each do |obj|
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obj.assemble io
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end
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end
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# set the next executed block after self.
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# why is this useful? if it's unconditional, why not merge them:
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# So the second block can be used as a jump target. You standard loop needs a block to setup
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# and at least one to do the calculation
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def set_next block
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@next = block
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end
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# sugar to create instructions easily. Any method with one arg is sent to the machine and the result
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# (hopefully an instruction) added as code
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def method_missing(meth, *args, &block)
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if args.length == 2
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add_code CMachine.instance.send(meth , *args)
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else
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super
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end
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end
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end
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end |