47 lines
1.6 KiB
Ruby
47 lines
1.6 KiB
Ruby
module Register
|
|
|
|
# SetSlot moves data into memory from a register.
|
|
# GetSlot moves data into a register from memory.
|
|
# Both use a base memory (a register)
|
|
|
|
# While the virtual machine has only one instruction (Set) to move data between slots,
|
|
# the register has two, namely GetSlot and SetSlot
|
|
#
|
|
# This is because that is what cpu's can do. In programming terms this would be accessing
|
|
# an element in an array, in the case of SetSlot setting the register in the array.
|
|
|
|
# btw: to move data between registers, use RegisterTransfer
|
|
|
|
class SetSlot < Instruction
|
|
|
|
# If you had a c array and index offset
|
|
# the instruction would do array[index] = register
|
|
# So SetSlot means the register (first argument) moves to the slot (array and index)
|
|
def initialize source , register , array , index
|
|
super(source)
|
|
@register = register
|
|
@array = array
|
|
@index = index
|
|
raise "not integer #{index}" unless index.is_a? Numeric
|
|
raise "Not register #{register}" unless Register::RegisterValue.look_like_reg(register)
|
|
raise "Not register #{array}" unless Register::RegisterValue.look_like_reg(array)
|
|
end
|
|
attr_accessor :register , :array , :index
|
|
def to_s
|
|
"SetSlot: #{register} -> #{array} [#{index}]"
|
|
end
|
|
|
|
end
|
|
|
|
# Produce a SetSlot instruction.
|
|
# From and to are registers or symbols that can be transformed to a register by resolve_to_register
|
|
# index resolves with resolve_index.
|
|
def self.set_slot source , from , to , index
|
|
from = resolve_to_register from
|
|
index = resolve_index( to , index)
|
|
to = resolve_to_register to
|
|
SetSlot.new( source, from , to , index)
|
|
end
|
|
|
|
end
|