131 lines
4.3 KiB
Ruby
131 lines
4.3 KiB
Ruby
require "asm/assembly_error"
|
|
require "asm/arm/instruction_tools"
|
|
require "asm/arm/normal_builder"
|
|
require "asm/arm/memory_access_builder"
|
|
require "asm/arm/stack_builder"
|
|
|
|
module Asm
|
|
module Arm
|
|
|
|
class Instruction
|
|
include InstructionTools
|
|
|
|
COND_POSTFIXES = Regexp.union(%w(eq ne cs cc mi pl vs vc hi ls ge lt gt le al)).source
|
|
def initialize(node)
|
|
@node = node
|
|
opcode = node.opcode
|
|
args = node.args
|
|
|
|
opcode = opcode.downcase
|
|
@cond = :al
|
|
if (opcode =~ /(#{COND_POSTFIXES})$/)
|
|
@cond = $1.to_sym
|
|
opcode = opcode[0..-3]
|
|
end unless opcode == 'teq'
|
|
if (opcode =~ /s$/)
|
|
@s = true
|
|
opcode = opcode[0..-2]
|
|
else
|
|
@s = false
|
|
end
|
|
@opcode = opcode.downcase.to_sym
|
|
@args = args
|
|
end
|
|
attr_reader :opcode, :args , :position
|
|
|
|
def affect_status
|
|
@s
|
|
end
|
|
|
|
def at position
|
|
@position = position
|
|
end
|
|
|
|
def length
|
|
4
|
|
end
|
|
|
|
RelocHandler = nil # Asm::Arm.method(:write_resolved_relocation)
|
|
|
|
def assemble(io, as)
|
|
s = @s ? 1 : 0
|
|
case opcode
|
|
when :adc, :add, :and, :bic, :eor, :orr, :rsb, :rsc, :sbc, :sub
|
|
builder = NormalBuilder.new(OPC_DATA_PROCESSING, OPCODES[opcode], s)
|
|
builder.cond = COND_CODES[@cond]
|
|
builder.rd = reg_ref(args[0])
|
|
builder.rn = reg_ref(args[1])
|
|
builder.build_operand args[2] , self.position
|
|
builder.assemble io, as
|
|
when :cmn, :cmp, :teq, :tst
|
|
builder = NormalBuilder.new(OPC_DATA_PROCESSING, OPCODES[opcode], 1)
|
|
builder.cond = COND_CODES[@cond]
|
|
builder.rn = reg_ref(args[0])
|
|
builder.rd = 0
|
|
builder.build_operand args[1]
|
|
builder.assemble io, as
|
|
when :mov, :mvn
|
|
builder = NormalBuilder.new(OPC_DATA_PROCESSING, OPCODES[opcode], s)
|
|
builder.cond = COND_CODES[@cond]
|
|
builder.rn = 0
|
|
builder.rd = reg_ref(args[0])
|
|
builder.build_operand args[1]
|
|
builder.assemble io, as
|
|
when :strb, :str
|
|
builder = MemoryAccessBuilder.new(OPC_MEMORY_ACCESS, (opcode == :strb ? 1 : 0), 0)
|
|
builder.cond = COND_CODES[@cond]
|
|
builder.rd = reg_ref(args[1])
|
|
builder.build_operand args[0]
|
|
builder.assemble io, as, self
|
|
when :ldrb, :ldr
|
|
builder = MemoryAccessBuilder.new(OPC_MEMORY_ACCESS, (opcode == :ldrb ? 1 : 0), 1)
|
|
builder.cond = COND_CODES[@cond]
|
|
builder.rd = reg_ref(args[0])
|
|
builder.build_operand args[1]
|
|
builder.assemble io, as, self
|
|
when :push, :pop
|
|
# downward growing, decrement before memory access
|
|
# official ARM style stack as used by gas
|
|
if (opcode == :push)
|
|
builder = StackBuilder.new(1,0,1,0)
|
|
else
|
|
builder = StackBuilder.new(0,1,1,1)
|
|
end
|
|
builder.cond = COND_CODES[@cond]
|
|
builder.rn = 13 # sp
|
|
builder.build_operand args
|
|
builder.assemble io, as
|
|
when :b, :bl
|
|
arg = args[0]
|
|
if (arg.is_a?(Asm::NumLiteral))
|
|
jmp_val = arg.value >> 2
|
|
packed = [jmp_val].pack('l')
|
|
# signed 32-bit, condense to 24-bit
|
|
# TODO add check that the value fits into 24 bits
|
|
io << packed[0,3]
|
|
elsif (arg.is_a?(Asm::LabelObject) or arg.is_a?(Asm::Label))
|
|
#not yet tested/supported
|
|
# arg = @ast_asm.object_for_label(arg.label, self) if arg.is_a?(Asm::Label)
|
|
# as.add_relocation(io.tell, arg, Asm::Arm::R_ARM_PC24, RelocHandler)
|
|
#write 0 "for now" and let relocation happen
|
|
io << "\x00\x00\x00"
|
|
else
|
|
raise "else not coded #{arg.inspect}"
|
|
end
|
|
io.write_uint8 OPCODES[opcode] | (COND_CODES[@cond] << 4)
|
|
when :swi
|
|
arg = args[0]
|
|
if (arg.is_a?(Asm::NumLiteral))
|
|
packed = [arg.value].pack('L')[0,3]
|
|
io << packed
|
|
io.write_uint8 0b1111 | (COND_CODES[@cond] << 4)
|
|
else
|
|
raise Asm::AssemblyError.new(Asm::ERRSTR_INVALID_ARG, arg)
|
|
end
|
|
else
|
|
raise Asm::AssemblyError.new("unknown instruction #{opcode}", @node)
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end |