Which data structures are used in pass 2
Pass 2 Data Structures
A table, the Machine-operation Table (MOT), that indicates for each instruction, symbolic mnemonic, length (two, four, or six bytes), binary machine opcode and format of instruction. 4.
Which data structures are used by the first pass of assembler
Data Structures. The assembler generates two data structures for later use by the interpreter. The first is the code section which holds the P-code instructions instructions in assembled form and will also be used by the assembler as an extension to the label table for handling forward references.
What are the functions of passes used in two pass assembler
Pass-2 of assembler generates machine code by converting symbolic machine-opcodes into their respective bit configuration(machine understandable form).
Pass-1:
- Define symbols and literals and remember them in symbol table and literal table respectively.
- Keep track of location counter.
- Process pseudo-operations.
What is the main purpose of the first pass of a two pass assembler
This is known as a two-pass assembler. Each pass scans the program, the first pass generates the symbol table and the second pass generates the machine code.
What is the difference between one pass and two pass assembler
Difference between One Pass and Two Pass Assemblers
The one pass assembler prepares an intermediate file, which is used as input by the two pass assembler. A two pass assembler does two passes over the source file (the second pass can be over an intermediate file generated in the first pass of the assembler).
What is the need for Symtab in assembler
The symbol table contains information to locate and relocate symbolic definitions and references. The assembler creates the symbol table section for the object file. It makes an entry in the symbol table for each symbol that is defined or referenced in the input file and is needed during linking.
Why assembler design is two pass design explain with example
The main reason why most assemblers use a 2-pass system is to address the problem of forwarding references — references to variables or subroutines that have not yet been encountered when parsing the source code.
Which data structures of pass I are used in pass II of assembler
Assembler implementation is based on two major data structures: Operation Table (OPTAB) and Symbol Table (SYMTAB).
What is two pass macro processor
A macro processor is a program that copies a stream of text from one place to another, making a systematic set of replacements as it does so. Macro processors are often embedded in other programs, such as assemblers and compilers.
What is Optab in system programming
In pass 1 the OPTAB is used to look up and validate the operation code in the source program and to find the instruction length for incrementing LOCCTR. In pass 2, it is used to translate the operation codes to machine language. (OPTAB is usually organized as a hash table, with mnemonic operation code as the key.
What is an Assembly directive
Assembler directives supply data to the program and control the assembly process. Assembler directives enable you to do the following: Assemble code and data into specified sections. Reserve space in memory for uninitialized variables. Control the appearance of listings.
What is forward reference how it is resolved by assembler
A forward reference occurs when a label is used as an operand, for example as a branch target, earlier in the code than the definition of the label. The assembler cannot know the address of the forward reference label until it reads the definition of the label.
What are the different data structures used in two pass assembler
Assembler implementation is based on two major data structures: Operation Table (OPTAB) and Symbol Table (SYMTAB).
What is the output of first pass of the assembler
Each pass scans the program, the first pass generates the symbol table and the second pass generates the machine code.
What is pass in assembler
During the first pass, the assembler checks to see if the instructions are legal in the current assembly mode. Second pass. During the second pass, the assembler examines the operands for symbolic references to storage locations and resolves these symbolic references using information in the symbol table.
What are the data structures used in design of macro processor
Solution(By Examveda Team) DEFTAB – Stores the macro definition including macro prototype and macro body. NAMTAB – Store macro names, which serves an index to DEFTAB contain pointers to the beginning and end of the definition.
What are the different types of assemblers used
On the basis of a number of phases used to convert to machine code, assemblers have two types:
- One-Pass Assembler. These assemblers perform the whole conversion of assembly code to machine code in one go.
- Multi-Pass/Two-Pass Assembler.
What is 1 pass and 2 pass assembler
The one pass assembler prepares an intermediate file, which is used as input by the two pass assembler. A two pass assembler does two passes over the source file (the second pass can be over an intermediate file generated in the first pass of the assembler).