For an ordinary near JMP in 8086/x86, which of the following flags are set by…
2012
For an ordinary near JMP in 8086/x86, which of the following flags are set by executing the instruction?
Answer: D. No flag is set — ConceptProcessor status flags record conditions produced by data-processing operations, such as a sign, carry, or auxiliary carry. Instruction side effects…
- A.
SF and CF
- B.
AF and CF
- C.
All flags
- D.
No flag is set
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Show answer & explanation
Correct answer: D
Concept
Processor status flags record conditions produced by data-processing operations, such as a sign, carry, or auxiliary carry. Instruction side effects are defined by the ISA; for the ordinary 8086/x86 JMP form assessed here, an unconditional control transfer changes the next instruction address without producing an arithmetic or logical result.
Application
Under the ordinary 8086/x86 JMP form, the processor loads the jump target into the instruction pointer and continues fetching from that address.
The flags register is left unchanged: JMP neither forces SF, AF, or CF to 1 nor clears them; any values already present remain intact.
Contrast
SF and CF are status flags associated with the sign of a result and an unsigned carry or borrow.
AF and CF are carry-related status flags for the low-nibble boundary and the most-significant-bit boundary.
All flags includes both status and control flags, which are affected only by their relevant instruction classes.
No flag is set describes an instruction that redirects control flow while preserving the existing flags register.
Result
Therefore, executing JMP sets no flag; the accepted value is “No flag is set.”