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refactor memory instruction (needs better tests)

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This commit is contained in:
Torsten Ruger 2016-12-16 15:40:52 +02:00
parent 190a0ffa47
commit 5cd05f6135
1 changed files with 30 additions and 28 deletions
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58
lib/arm/instructions/memory_instruction.rb
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@ -16,7 +16,6 @@ module Arm
@attributes[:condition_code] = :al if @attributes[:condition_code] == nil
@operand = 0
raise "alert" if right.is_a? Register::Label
@pre_post_index = @attributes[:pre_post_index] ? 0 : 1 #P flag
@add_offset = @attributes[:add_offset] ? 0 : 1 #U flag
@is_load = opcode.to_s[0] == "l" ? 1 : 0 #L (load) flag
end
@ -25,30 +24,19 @@ module Arm
# don't overwrite instance variables, to make assembly repeatable
#TODO better test, this operand integer (register) does not work.
def assemble(io)
rn , operand , add_offset , arg = @rn , @operand , @add_offset , @left
arg = @left
arg = arg.symbol if( arg.is_a? ::Register::RegisterValue )
is_reg = arg.is_a?(::Register::RegisterValue)
if( arg.is_a?(Symbol) and not is_reg)
is_reg = (arg.to_s[0] == "r")
end
is_reg = (arg.to_s[0] == "r") if( arg.is_a?(Symbol) and not is_reg)
raise "invalid operand argument #{arg.inspect} #{inspect}" unless (is_reg )
rn = arg
if @right
operand = @right
operand = operand.symbol if operand.is_a? ::Register::RegisterValue
unless( operand.is_a? Symbol) #TODO test/check/understand
add_offset = (operand < 0) ? 0 : 1
operand *= -1 if (operand < 0)
raise "offset too large (max 4095) #{arg} #{inspect}" if (@operand.abs > 4095)
end
end
operand = get_operand
#not sure about these 2 constants. They produce the correct output for str r0 , r1
# but i can't help thinking that that is because they are not used in that instruction and
# so it doesn't matter. Will see
if (operand.is_a?(Symbol) or operand.is_a?(::Register::RegisterValue))
val = reg_code(operand)
@pre_post_index = 0
i = 1 # not quite sure about this, but it gives the output of as. read read read.
else
i = 0 #I flag (third bit)
@ -57,23 +45,37 @@ module Arm
# testing against gnu as, setting the flag produces correct output
# but gnu as produces same output for auto_inc or not, so that seems broken
# luckily auto_inc is not used and even if it clobbers unused reg in soml, but still
@pre_post_index = 1
op = shift_handling
val = shift(val , 0 ) # for the test
val |= shift(op , 0)
val = shift(val , 0 )
val |= shift(reg_code(arg) , 16)
val |= shift(i , 25)
write_val(val, io)
end
def write_val(val, io)
val |= shift(shift_handling , 0)
val |= shift(reg_code(@result) , 12 )
val |= shift(reg_code(rn) , 12 + 4) #16
val |= shift(@is_load , 12 + 4 + 4)
val |= shift(0 , 12 + 4 + 4 + 1)
val |= shift(byte_access , 12 + 4 + 4 + 1 + 1)
val |= shift(add_offset , 12 + 4 + 4 + 1 + 1 + 1)
val |= shift(@pre_post_index, 12 + 4 + 4 + 1 + 1 + 1 + 1)#24
val |= shift(i , 12 + 4 + 4 + 1 + 1 + 1 + 1 + 1)
val |= shift(@is_load , 20)
val |= shift(byte_access , 22)
val |= shift(add_offset , 23)
val |= shift(0, 21)
val |= shift(1, 24) #pre_post index , not used
val |= instruction_code
val |= condition_code
io.write_uint32 val
end
def get_operand
return @operand unless @right
operand = @right
operand = operand.symbol if operand.is_a? ::Register::RegisterValue
unless( operand.is_a? Symbol)
# TODO test/check/understand: has no effect in current tests
# add_offset = (operand < 0) ? 0 : 1
operand *= -1 if (operand < 0)
raise "offset too large (max 4095) #{arg} #{inspect}" if (@operand.abs > 4095)
end
operand
end
def instuction_class
0b01 # OPC_MEMORY_ACCESS
end