40 lines
1.2 KiB
Ruby
40 lines
1.2 KiB
Ruby
module Arm
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class SyscallImplementation
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CALLS_CODES = { :putstring => 4 , :exit => 1 }
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def run block
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block.codes.dup.each do |code|
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next unless code.is_a? Register::Syscall
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new_codes = []
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int_code = CALLS_CODES[code.name]
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raise "Not implemented syscall, #{code.name}" unless int_code
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send( code.name , int_code , new_codes )
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block.replace(code , new_codes )
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end
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end
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def putstring int_code , codes
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codes << ArmMachine.ldr( :r1 , Register.message_reg, 4 * Register.resolve_index(:message , :receiver))
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codes << ArmMachine.add( :r1 , :r1 , 8 )
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codes << ArmMachine.mov( :r0 , 1 ) # stdout == 1
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codes << ArmMachine.mov( :r2 , 12 ) # String length, obvious TODO
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syscall(int_code , codes )
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end
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def exit int_code , codes
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syscall int_code , codes
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end
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private
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# syscall is always triggered by swi(0)
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# The actual code (ie the index of the kernel function) is in r7
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def syscall int_code , codes
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codes << ArmMachine.mov( :r7 , int_code )
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codes << ArmMachine.swi( 0 )
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end
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end
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Virtual.machine.add_pass "Arm::SyscallImplementation"
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end
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