68 lines
1.6 KiB
Ruby
68 lines
1.6 KiB
Ruby
module Risc
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# A branch must branch to a label.
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# Different Branches (derived classes) use different registers, the base
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# just stores the Label
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class Branch < Instruction
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def initialize( source , label )
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super(source)
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@label = label
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end
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attr_reader :label
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def to_s
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case label
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when Label
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str = label.name
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when Parfait::BinaryCode
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str = "Code"
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str += ":#{Position.get(label)}" if Position.set?(label)
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else
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str = "(no label)"
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end
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class_source( str )
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end
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alias :inspect :to_s
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# if branch_to is implemented it must return the label it branches to
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def branch_to
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label
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end
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end
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# dynamic version of an Branch branch that jumps to the contents
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# of a register instead of a hardcoded address
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# As Branches jump to Labels, this is not derived from Branch
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# PS: to conditionally jump to a dynamic adddress we do a normal branch
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# over the dynamic one and then a dynamic one. Save us having all types of branches
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# in two versions
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class DynamicJump < Instruction
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def initialize( source , register )
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super(source)
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@register = register
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end
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attr_reader :register
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end
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# A Dynamic yield is very much like a DynamicJump, especially in it's idea
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#
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# The implentation differes slightly, as we use a chache entry in the DynamicJump
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# but a block in the DynamicYield.
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# Using means that we assume the register to be ready loaded with a Block
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class DynamicYield < DynamicJump
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end
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class IsZero < Branch
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end
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class IsNotZero < Branch
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end
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class IsMinus < Branch
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end
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class IsPlus < Branch
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end
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end
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