Hazard Detection

Concept

Hazard detection is a pipeline-control concern in pipelined microprocessors: it identifies situations where overlapped instruction execution cannot safely proceed under the sequential ISA semantics and triggers handling such as stalling, forwarding, or cancellation. The provided evidence describes data hazards that stall decode, load/use hazards that can be handled by forwarding, and branch mispredictions that cancel in-flight instructions.

First seen 5/25/2026

Last seen 5/25/2026

Evidence 3 chunks

Wiki v1

WIKI

Overview

In a pipelined microprocessor, multiple instructions are overlapped to improve performance, even though the instruction set architecture (ISA) defines behavior as strict sequential execution over architectural state such as registers, the program counter, and memory. To keep pipelined execution faithful to those sequential ISA semantics, implementations use mechanisms such as interlocking and data forwarding. Hazard detection is the pipeline-control role that recognizes hazard conditions in this overlapped execution and initiates the appropriate response, such as stalling or using forwarding. [C1]

Role in pipelined execution

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LINKED ENTITIES

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pipelining REQUIRES Extracted graph relationship

CITATIONS

6 sources

6 citations — click to expand

[1] C1: Pipelined processors overlap instructions, while interlocking and data forwarding help preserve sequential ISA semantics. Formal Verification of Pipelined Y86-64 Microprocessors with UCLID5

[2] C2: Pipeline stalls for hazard conditions and instruction cancellation after branch misprediction can be zero-progress cycles in safety verification. Formal Verification of Pipelined Y86-64 Microprocessors with UCLID5

[3] C3: In the STALL pipeline variant, an instruction stalls in decode for up to three cycles when a downstream instruction imposes a data hazard. Formal Verification of Pipelined Y86-64 Microprocessors with UCLID5

[4] C4: An added forwarding path can resolve some load/use hazards by forwarding rather than stalling. Formal Verification of Pipelined Y86-64 Microprocessors with UCLID5

[5] C5: Branch-prediction variants may cancel up to two instructions after a branch misprediction. Formal Verification of Pipelined Y86-64 Microprocessors with UCLID5

[6] C6: Liveness verification is needed to show that the processor cannot remain forever without forward progress and that the pipeline does not stall indefinitely. Formal Verification of Pipelined Y86-64 Microprocessors with UCLID5