Current Project: Disassembler

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Current Project Disassembler

• Input 32-bit instruction (binary word)
• Output assembly code based on fields in the
  instruction ( add r1, r2, r3 )
• To do this
• Edit machine.def file for proper output format
  (called OPFORMAT)
• Use example disassembler (simplescalar) to
  generate own code

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Disassembler Code

• Arrays of fields in machine.def
• (name, opform, decode mask, proper decode result)

• Instruction Decoder masks instruction passed in
  with each decode mask, if it matches decode
  result, then this is the proper instruction

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Disassembler Code

• Code to print instruction ( print parts of
  instructions based on characters in OPFORM field )

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Challenges / Other Work

• Need to decode instruction fields within the
  instruction for comparisons (assembler should
  output specific comparison) complete but not
  yet tested
• Plug Disassembler into simplescalar to test full
  functionality