52 lines
1.8 KiB
Ruby
52 lines
1.8 KiB
Ruby
module Register
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# the register machine has at least 8 registers, named r0-r5 , :lr and :pc (for historical reasons)
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# we can load and store their contents and
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# access (get/set) memory at a constant offset from a register
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# while the vm works with objects, the register machine has registers,
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# but we keep the names for better understanding, r4/5 are temporary/scratch
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# there is no direct memory access, only through registers
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# constants can/must be loaded into registers before use
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class Instruction
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def initialize source
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@source = source
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end
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attr_reader :block , :source
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# returns an array of registers (RegisterReferences) that this instruction uses.
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# ie for r1 = r2 + r3
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# which in assembler is add r1 , r2 , r3
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# it would return [r2,r3]
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# for pushes the list may be longer, whereas for a jump empty
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def uses
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raise "abstract called for #{self.class}"
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end
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# returns an array of registers (RegisterReferences) that this instruction assigns to.
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# ie for r1 = r2 + r3
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# which in assembler is add r1 , r2 , r3
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# it would return [r1]
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# for most instruction this is one, but comparisons and jumps 0 , and pop's as long as 16
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def assigns
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raise "abstract called for #{self.class}"
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end
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# wrap symbols into regsiter reference if needed
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def wrap_register reg
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return reg if reg.is_a? RegisterReference
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RegisterReference.new(reg)
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end
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end
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end
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require_relative "instructions/set_slot"
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require_relative "instructions/get_slot"
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require_relative "instructions/load_constant"
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require_relative "instructions/syscall"
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require_relative "instructions/function_call"
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require_relative "instructions/function_return"
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require_relative "instructions/save_return"
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require_relative "instructions/register_transfer"
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require_relative "instructions/branch"
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