Enumerate data structures used during 1-pass of assembler, Computer Engineering

Assignment Help:

Enumerate the data structures used during the first pass of the assembler. Indicate the fields of these data structures and their purpose/usage.

Three main data structures used throughout the first pass of the assembler are given below:

- LOCCTR i.e. Location counter

- OPTAB i.e. operation code table

- SYMTAB i.e. Symbol table

LOCCTR: It is Location Counter that maintains track machine addresses of symbolic tables.

  • Initialized with START.
  • Raised for all instructions
  • Pseudo Instructions are: BYTE, WORD, RESB and RESW.
  • Machine Instructions are: Fixed length (i.e. 3 bytes) for SIC, variable length for SIC/XE (looking up OPTAB).
  • Allocate the value (address) of LOCCTR to consequent symbol table.

OPTAB: In this operation table mnemonic operation code and have its machine language equivalent.

346_OPTAB.png

  OPTAB can be implemented by using hashing function for fast access.

  SYMTAB: in Symbol table symbolic label, operand and their consequent machine are keeps addresses.

656_SYMTAB.png

  • SYMTAB is dynamic, constructed throughout Pass 1:

                   a. For symbolic label, fill in address and symbol (as per to current LOCCTR).

                   b. For symbolic operand, fill into symbol and mark this as undefined. Address field will be challenged later.

  • SYMTAB can be implemented by using hashing function for fast access.

Related Discussions:- Enumerate data structures used during 1-pass of assembler

With respect to security which is the better .net or j2ee, With respect to...

With respect to security, which one is the better choice?.Net or J2EE? Explain? As per majority programmers .NET is the best one which have one vendor compare to, the ease of

State the use of erasable programmable read only memory, Erasable programma...

Erasable programmable read only memory (EPROM) This is a special type of PROM which can be erased by exposing it to ultraviolet (UV) light. Once it has been erased, it can be r

Fuzzy logic - artificial intelligence, Fuzzy Logic: In the logics we a...

Fuzzy Logic: In the logics we are here described above, what we have been concerned with truth: whether propositions and sentences are true. Moreover, with some natural langua

Explain advantage of static storage class, Explain advantage of static stor...

Explain advantage of static storage class The second and more subtle use of 'static' is in connection with external declarations. With external constructs it provides a privacy

What are the logic micro-operations, Q. What are the Logic Micro-operations...

Q. What are the Logic Micro-operations? Logic operations are fundamentally binary operations that are performed on string of bits stored in the registers. For a logic micro-ope

Determine the statement for array, Q. Determine the statement for array? ...

Q. Determine the statement for array? Determine the statement ALIGN A[i] WITH B[i] This statement aligns every A[i] with B[i] as displayed in Figure below. Figure

Draw the logic diagram of 4-bit twisted ring counters, Draw the logic diagr...

Draw the logic diagram of 4-bit Twisted Ring counters and explain its operation with the help of timing diagram. Ans: Twisted ring counter (4 BIT): We ready know that shi

Parallel computer architecture , Parallel Computer Architecture Intr...

Parallel Computer Architecture Introduction We have talked about the classification of parallel computers and their interconnection networks in that order in units 2 and

What are transmission bridges, What are transmission bridges? A usual ...

What are transmission bridges? A usual transmission bridge is demonstrated in figure. The series capacitance and the shunt inductances of the two relays give a high-pass filte

What is an accessor in c++, An accessor is a class operation that does not ...

An accessor is a class operation that does not change the state of an object in C++. The access or functions require to be declared as const operations

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd