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fix misunderstood mov usage

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When moving a reference (pointer) to a register
one needs to ADD to the pc
i.e. one needs an add, not mov instruction
This commit is contained in:
Torsten Ruger 2015-06-26 20:00:33 +03:00
parent 32e1903884
commit 37403f1139
2 changed files with 8 additions and 32 deletions
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21
lib/arm/instructions/move_instruction.rb
View File

@ -4,6 +4,9 @@ module Arm
def initialize to , from , options = {}
super(options)
if( from.is_a?(Symbol) and Register::RegisterReference.look_like_reg(from) )
from = Register::RegisterReference.new(from)
end
@from = from
@to = to
raise "move must have from set #{inspect}" unless from
@ -35,14 +38,6 @@ module Arm
operand = @operand
immediate = @immediate
right = @from
if right.is_a?(Parfait::Object)
r_pos = right.position
# do pc relative addressing with the difference to the instuction
# 8 is for the funny pipeline adjustment (ie pc pointing to fetch and not execute)
right = r_pos - self.position - 8
puts "Position #{r_pos} from #{self.position} = #{right}"
rn = :pc
end
if (right.is_a?(Numeric))
if (right.fits_u8?)
# no shifting needed
@ -79,7 +74,7 @@ module Arm
# The way it _should_ be done
# is to check that the first part is doabe with u8_with_rr AND leaves a u8 remainder
end
elsif (right.is_a?(Symbol) or right.is_a?(::Register::RegisterReference))
elsif( right.is_a? Register::RegisterReference)
operand = reg_code(right)
immediate = 0 # ie not immediate is register
else
@ -92,10 +87,10 @@ module Arm
val |= shift(reg_code(@to) , 12)
val |= shift(reg_code(rn) , 12+4)
val |= shift(@attributes[:update_status] , 12+4+4)#20
val |= shift(op_bit_code , 12+4+4 +1)
val |= shift(immediate , 12+4+4 +1+4)
val |= shift(instuction_class , 12+4+4 +1+4+1)
val |= shift(cond_bit_code , 12+4+4 +1+4+1+2)
val |= shift(op_bit_code , 12+4+4 + 1)
val |= shift(immediate , 12+4+4 + 1+4)
val |= shift(instuction_class , 12+4+4 + 1+4+1)
val |= shift(cond_bit_code , 12+4+4 + 1+4+1+2)
io.write_uint32 val
# by now we have the extra add so assemble that
if(@extra)

19
test/arm/test_move.rb
View File

@ -32,23 +32,4 @@ class TestMoves < MiniTest::Test
code = @machine.mvn :r1, 5
assert_code code , :mvn , [0x05,0x10,0xe0,0xe3] #e3 e0 10 05
end
def test_constant_small # like test_mov
const = :harvey
const.set_position( 13 ) # 13 = 5 + 8 , 8 for the arm pipeline offset, gets subtracted
code = @machine.mov :r1 , 5
code.set_position(0)
#TODO check this in decompile
assert_code code , :mov , [0x05,0x10,0xa0,0xe3] #e3 ef 10 05
end
def test_constant_big # like test_mov_big
const = :harvey
const.set_position( 0x222 )
code = @machine.mov :r0 , 0x222
code.set_position(0)
begin # mov 512(0x200) = e3 a0 0c 02 add 34(0x22) = e2 80 00 22
assert_code code , :mov , [ 0x02,0x0c,0xa0,0xe3 , 0x22,0x00,0x80,0xe2]
rescue Register::LinkException
retry
end
end
end