rubyx/lib/arm/arm_machine.rb
2014-05-21 19:43:46 +03:00

100 lines
3.1 KiB
Ruby

require "vm/register_machine"
require_relative "stack_instruction"
require_relative "logic_instruction"
require_relative "move_instruction"
require_relative "compare_instruction"
require_relative "memory_instruction"
require_relative "call_instruction"
require_relative "constants"
module Arm
class ArmMachine < Vm::RegisterMachine
def integer_less_or_equal block , left , right
block << cmp( left , right )
Vm::Bool.new
end
def integer_plus block , result , left , right
block << add( result , left , right )
result
end
def integer_minus block , result , left , right
block << sub( result , left , right )
result
end
def integer_load block , to , from
block << mov( to , from )
to
end
def integer_move block , to , from
block << mov( to , from )
to
end
def function_call into , call
raise "Not CallSite #{call.inspect}" unless call.is_a? Vm::CallSite
raise "Not linked #{call.inspect}" unless call.function
into << call( call.function )
raise "No return type for #{call.function.name}" unless call.function.return_type
call.function.return_type
end
def main_start entry
entry << mov( :fp , 0 )
end
def main_exit exit
syscall(exit , 1)
exit
end
def function_entry block, f_name
block << push( [:lr] )
end
def function_exit entry , f_name
entry << pop( [:pc] )
end
# assumes string in r0 and r1 and moves them along for the syscall
def write_stdout block
block.instance_eval do
mov( :r2 , :r1 )
mov( :r1 , :r0 )
mov( :r0 , 1 ) # 1 == stdout
end
syscall( block , 4 )
end
# the number (a Vm::integer) is (itself) divided by 10, ie overwritten by the result
# and the remainder is overwritten (ie an out argument)
# not really a function, more a macro,
def div10 block, number , remainder
# Note about division: devision is MUCH more expensive than one would have thought
# And coding it is a bit of a mind leap: it's all about finding a a result that gets the
# remainder smaller than an int. i'll post some links sometime. This is from the arm manual
block.instance_eval do
sub( remainder , number , 10 )
sub( number , number , number , shift_lsr: 2)
add( number , number , number , shift_lsr: 4)
add( number , number , number , shift_lsr: 8)
add( number , number , number , shift_lsr: 16)
mov( number , number , shift_lsr: 3)
tmp = function.new_local
add( tmp , number , number , shift_lsl: 2)
sub( remainder , remainder , tmp , shift_lsl: 1 , update_status: 1)
add( number , number, 1 , condition_code: :pl )
add( remainder , remainder , 10 , condition_code: :mi )
end
end
def syscall block , num
block << mov( :r7 , num )
block << swi( 0 )
Vm::Integer.new(0) #small todo, is this actually correct for all (that they return int)
end
end
end