@returns 0–7 to indicate data registers 0 to 7, or 8–15 to indicate address registers 0 to 7 respectively. Provides undefined results if the addressin

@returns The @c Operation performed by this instruction.

@returns The full PC + status bits.

Adds @c half_cycles half cycles to the amount of time that has passed.

! Advances time. This class manages the AY's concept of time to permit updating-on-demand. */

@returns The immediate segment value provided with this instruction, if any. Relevant for far calls and jumps; e.g. `JMP 1234h:5678h` will have a seg

Contractually, this serialises as BSON. */

Sign-extend @c x to 32 bits and return as an unsigned 32-bit int.

! Advances the phase generator a single step, given the current state of the low-frequency oscillator, @c oscillator. */

TODO: verify attenuation scales pervasively below.

@returns The byte size of this sector, according to its address mark.

Expands @c source from b15 ... b0 to 000b15 ... 000b0.

Requests a flush of any pending audio or video output.

! Advances to the next block on the tape, treating it as a header, then consumes, parses, and returns it. Returns @c nullptr if any wave-encoding le

! @returns whether the output is currently retracing. */

@c true if the status register should be updated; @c false otherwise.

Sets the VPA (valid peripheral address) line — @c true for active, @c false for inactive.

Sets the N and Z flags according to the value of @c result.

! Sets the period of this generator, along with its current octave. Yamaha tends to refer to the period as the 'f-number', and used both 'octave'

! Sets the relative volumes of the various sources underlying this compound. The caller should ensure that the number of items supplied matches

! Enables or disables damping on this envelope generator. If damping is enabled then this envelope generator will use the damping phase when neces

Sets the current value of the status register; @returns @c true if the processor finishes in supervisor mode; @c false otherwise.

Updartes the LFSR output. Should be called at the input clock rate.

! @returns the value currently on the high 8 lines of the data bus. */

! @returns How many cycles the [ULA/gate array] would delay the CPU for if it were to recognise that contention needs to be applied in @c offset h

Reset decoding.

@returns The condition code evaluated by this instruction if applicable. If this instruction is not conditional, the result is undefined.

Evaluates @c condition.

Flushes any queued behaviour (which, specifically, means on the AY).

@returns The current value of the DRQ line output.

MARK: - Configuration options.