Language Support

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

Instructions

Instruction	Support	Updated
ADD, SUB	Supported for operands of the same data type. Wraps on overflow.	Dec. 2023
CAPTURE	Supported. See Waveforms below for details.	Sep. 2020
DECLARE	Supported. See Binary Representation below for details.
DELAY	Full support.	Sep. 2020
DIV, MUL	Supported: for operands of the same data type when the latter operand is a literal power of two, $v: -2^{47} < v < 2^{47}$. 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	Supported for literal values. Unitless Factor $s : -4 ≤ s ≤ 4$ Parametric values estimated to be supported in 2024.	Dec. 2023
MOVE	Supported between regions of the same data type.	Dec. 2023
AND, IOR, NEG, NOT, OR, XOR	Not supported. Estimated to be supported in 2024.
EQ, GE, GT, LE, LT	Not supported. Estimated to be supported in 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