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Clockless Computing. Montek Singh Thu, Sep 20, 2007. More on Asynchronous Pipelines (one classic and two latest approaches). Sutherland’s “micropipelines” 1989 Turing Award lecture Sutherland et al.’s “GasP” pipelines 2001 ASYNC Best Paper Award IBM’s “IPCMOS” pipelines
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Clockless Computing Montek Singh Thu, Sep 20, 2007
More on Asynchronous Pipelines(one classic and two latest approaches) • Sutherland’s “micropipelines” • 1989 Turing Award lecture • Sutherland et al.’s “GasP” pipelines • 2001 ASYNC Best Paper Award • IBM’s “IPCMOS” pipelines • 2000; very highly publicized; holds current “record” for speed
Sutherland’s Micropipelines (1989) • Basic FIFO (no logic)
Sutherland’s Micropipelines (1989) • Pipeline with logic • Also: more robust construction
Sutherland’s Micropipelines (1989) • Details of the storage elements: • “capture-pass” latches
GasP PipelinesSutherland & Fairbanks [2001] • A “minimal” control circuit for pipelines • Very highly regarded; “cool” • But… fairly low-level design • Transistor level • Stringent (2-sided) timing requirements
ackin ackout stagecontrol reqin reqout En (latchenable) datainputs dataoutputs latch GasP: A Pipeline Stage
IPCMOS (IBM 2000) • “Interlocked Pipelined CMOS” • Really fast: 3.3GHz in 0.18 • Even faster (4.5GHz) for extreme corner cases • Bragging rights! • But … very low-level design • Transistor-level design • Stringent (2-sided) timing constraints • Not clear if it really should be that fast…! • Technology-independent comparison: unsure if faster than GasP
ackin ackout stagecontrol reqin1 reqinn reqout En (latchenable) datainputs dataoutputs latch IPCMOS: A Pipeline Stage
IPCMOS: Controller Details ackin reqout X En (latchenable) R1 Rn A switch switch ackout reqin1 reqinn “pulse catcher”
En Ri reqini (inputrequest) (conditionedrequest) Y reqout switch(“pulse catcher”) IPCMOS: Pulse Catcher