rubyx/lib/arm/translator.rb
Torsten Ruger 9005513368 rename typed_method to callable_method
seems to make the essence clearer
also extracted base class
2018-07-07 09:11:09 +03:00

172 lines
5.1 KiB
Ruby

module Arm
# A translator is cpu specific and translates from risc instructions to a given
# cpu. This one transltes to Arm Instructions.
class Translator
# translator should translate from register instructio set to it's own (arm eg)
# for each instruction we call the translator with translate_XXX
# with XXX being the class name.
# the result is replaced in the stream
def translate( instruction )
class_name = instruction.class.name.split("::").last
self.send( "translate_#{class_name}".to_sym , instruction)
end
def translate_Label( code )
Risc.label( code.source , code.name , code.address)
end
# arm indexes are
# in bytes, so *4
# if an instruction is passed in we get the index with index function
def arm_index( index )
index = index.index if index.is_a?(Risc::Instruction)
raise "index error #{index}" if index < 0
index * 4
end
def translate_Transfer( code )
# Risc machine convention is from => to
# But arm has the receiver/result as the first
ArmMachine.mov( code.to , code.from)
end
def translate_SlotToReg( code )
ArmMachine.ldr( *slot_args_for(code) )
end
def translate_RegToSlot( code )
ArmMachine.str( *slot_args_for(code) )
end
def slot_args_for( code )
if(code.index.is_a? Numeric)
[ code.register , code.array , arm_index(code) ]
else
[ code.register , code.array , code.index , :shift_lsl => 2]
end
end
def byte_args_for( code )
args = slot_args_for( code )
args.pop if(code.index.is_a? Numeric)
args
end
def translate_ByteToReg( code )
ArmMachine.ldrb( *byte_args_for(code) )
end
def translate_RegToByte( code )
ArmMachine.strb( *byte_args_for(code) )
end
def translate_FunctionCall( code )
ArmMachine.b( code.method.binary )
end
def translate_FunctionReturn( code )
ArmMachine.mov( :pc , code.register)
end
def translate_DynamicJump(code)
index = Parfait.object_space.get_class_by_name(:CallableMethod).instance_type.variable_index(:binary)
codes = ArmMachine.ldr( code.register , code.register , arm_index(index) )
codes << ArmMachine.mov( :pc , code.register)
codes
end
def translate_LoadConstant( code )
constant = code.constant
constant = constant.to_cpu(self) if constant.is_a?(Risc::Label)
return ArmMachine.add( code.register , constant )
end
def translate_LoadData( code )
return ArmMachine.mov( code.register , code.constant )
end
def translate_OperatorInstruction( code )
left = code.left
right = code.right
case code.operator.to_s
when "+"
c = ArmMachine.add(left , left , right)
when "-"
c = ArmMachine.sub(left , left , right)
when "&"
c = ArmMachine.and(left , left , right)
when "|"
c = ArmMachine.orr(left , left , right)
when "*"
c = ArmMachine.mul(left , right , left) #arm rule about left not being result, lukily commutative
when ">>"
c = ArmMachine.mov(left , left , :shift_asr => right) #arm rule about left not being result, lukily commutative
when "<<"
c = ArmMachine.mov(left , left , :shift_lsl => right) #arm rule about left not being result, lukily commutative
else
raise "unimplemented '#{code.operator}' #{code}"
end
c
end
# This implements branch logic, which is simply assembler branch
#
# The only target for a call is a Block, so we just need to get the address for the code
# and branch to it.
def translate_Branch( code )
target = code.label.is_a?(Risc::Label) ? code.label.to_cpu(self) : code.label
ArmMachine.b( target )
end
def translate_IsPlus( code )
ArmMachine.bpl( code.label.to_cpu(self) )
end
def translate_IsMinus( code )
ArmMachine.bmi( code.label.to_cpu(self) )
end
def translate_IsZero( code )
ArmMachine.beq( code.label.to_cpu(self) )
end
def translate_IsNotZero( code )
ArmMachine.bne( code.label.to_cpu(self) )
end
def translate_IsOverflow( code )
ArmMachine.bvs( code.label.to_cpu(self))
end
def translate_Syscall( code )
call_codes = { :putstring => 4 , :exit => 1 }
int_code = call_codes[code.name]
raise "Not implemented syscall, #{code.name}" unless int_code
send( code.name , int_code )
end
def putstring( int_code )
codes = ArmMachine.add( :r1 , :r1 , Parfait::Word.type_length*4 ) # adjust for object header
codes.append ArmMachine.mov( :r0 , 1 ) # write to stdout == 1
syscall(int_code , codes )
end
def exit( int_code )
codes = ArmMachine.mov( :r7 , int_code )
codes.append ArmMachine.swi( 0 )
codes
end
private
# syscall is always triggered by swi(0)
# The actual code (ie the index of the kernel function) is in r7
def syscall( int_code , codes)
codes.append ArmMachine.mov( :r7 , int_code )
codes.append ArmMachine.swi( 0 )
codes
end
end
end