Describe Data structures used during passes of assembler and their use.
During passes of assembler, the Data structures define as:
Pass 1 data base
- Input source program
- A location counters (LC)
- A machine-operation table (i.e. MOT), which indicates the symbolic mnemonic for each instruction and instruction's length.
- Pseudo- operation table
- Symbol table
- Literal table
- Copy of the input to be used later through pass 2
Pass 2
- Coping of source program input to pass 1
- Location counter (LC)
- MOT
- POT
- ST
- Base table which indicates that registers are currently identified as base register.
- A work space, INST, which used to hold instruction as its different parts are being assembled together
- Punch line, utilized to produce a printed listing.
- Punch card used for converting assembled instructions in the format required by the loader.