Language Support

The following describes which Quil syntax is supported on Ankaa-1 and later QPUs.

Instructions

Instruction
Support
Updated

ADD, SUB

Supported for INTEGERs and REALs. Wraps on overflow. NB: Prior to November 2024, ADD and SUB were also unintentionally supported on BITs. This is not part of the Quil spec; the replacement for both ADD and SUB on BITs is XOR.

Nov. 2024

CAPTURE

Supported.

Sep. 2020

DECLARE

DELAY

Full support.

Sep. 2020

DIV, MUL

Supported:

  • for operands of the same data type

Wraps on overflow.

Dec. 2023

FENCE

Supported.

Sep. 2020

LOAD, STORE

Supported. The dynamic offset value is bounds-checked at runtime to ensure memory safety; if out of bounds, the program terminates with a fixed error code. The region and offset value are not specified in that error code and must be inferred by the program author.

Dec. 2023

RAW-CAPTURE

Supported, with caveats:

  • One per program

  • No CAPTURE may be present in the program

  • Has a maximum duration which may vary based on the current implementation

This adds a delay to the end of the basic block in which it is invoked, in order to allow enough time for the values to be read from the control system. This time is proportional to the duration of the instruction. Some of these limitations are more fundamental than others; contact QCS support if they block you from a useful program. Note that the signal read out in this instruction is not from one qubit alone, but from a group of qubits. The groups depend on the device architecture and can be inferred from the Quil frame definition (for Ankaa and later QPUs). Look for the following attribute: ENABLE-RAW-CAPTURE: "true"

Sep. 2020

SET-FREQUENCY, SHIFT-FREQUENCY

Supported. Unit: Hertz

Sep. 2020

SET-PHASE, SHIFT-PHASE

Supported. Unit: Radians

Sep. 2020

SET-SCALE

Dec. 2023

SWAP-PHASES

Dec. 2023

MOVE

Supported between regions of the same data type.

Dec. 2023

AND, IOR,OR, XOR

Supported for INTEGERs and BITs.

Jul. 2024

EQ, GE, GT, LE, LT

Supported between regions of the same data type.

Sep. 2024

NEG, NOT

Supported for INTEGER and BITs.

Nov. 2024

NOP

Supported, but has no effect on the program.

Dec. 2023

CONVERT

Not supported.

LABEL JUMP, JUMP-WHEN, JUMP-UNLESS HALT

Supported. Diverging from the Quil spec, jump condition operand may be of any Quil datatype, not only BIT. Note that all of these instructions start a new basic block and thus no pulse program timing behavior is guaranteed across one.

Dec. 2023

EXCHANGE

Not supported.

Binary Representation

  • All values are encoded into 48 bits within our control system. The encoding depends on the point of use, irrespective of the Quil datatype:

    • The point of use is the way in which the value is consumed within the program. For example, memory values and literals used as phase values are encoded differently from those used as frequency values.

    • If the value is only used by the Quil program itself - such as a loop index - then it is encoded per its Quil datatype:

      • BIT, OCTET, INTEGER as signed 48-bit

      • REAL as s22.22 fixed-point

PRAGMAs

Unsupported and unrecognized PRAGMAs result in translation errors.

PRAGMA
Support

FILTER-NODE <qubit> "<filter spec>"

Configures the execution post-processing pipeline. Distributed with Quil calibrations and meant for use by QCS. Editing it is "safe" but may cause unexpected readout values to be returned from execution.

LOAD-MEMORY <qubit> <memory region>

Maps a qubit's readout stream to a memory regions to mimic shot-wise memory values. This mapping is returned to the translation client (e.g. pyquil) for use on the client side. Does not affect program execution.

TSUNAMI-ASSEMBLY "<assembly>"

Writes raw control system assembly into the compiled program. Limited to select users; requires special authorization and knowledge for proper use.

Waveforms

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