SSC IMD SA 2017 – Question 154

Which of the following statements is true?

• While dealing with branching code, the assembler replaces the target with its address.
• When dealing with branch code, the assembler does not replace until the test condition is satisfied.
• While dealing with branching code, the assembler finds the branch offset and replaces the branch target with it.
• While dealing with branch code, the assembler replaces the target with the value specified by the DATAWORD directive.

Detailed Explanation:

The correct answer is c) While dealing with branching code, the assembler finds the branch offset and replaces the branch target with it (ब्रांचिंग कोड के साथ काम करते समय, असेम्बलर शाखा ऑफसेट खोजता है और उसके साथ शाखा लक्ष्य को बदल देता है।).

When handling branch instructions (such as conditional jumps BEQ, BNE, or unconditional jumps JMP):

• In modern architectures, most branch instructions use PC-relative addressing rather than absolute addressing.
• The source code specifies a symbolic label as the target of the branch (e.g., BEQ LOOP).
• During assembly, the assembler computes the relative distance or branch offset:$$\text{Offset} = \text{Address}(\text{Target Label}) – \text{Address}(\text{Updated PC})$$
• The assembler replaces the symbolic target label in the machine code format with this computed numerical offset field. This allows position-independent code (PIC) execution.