hardware_interp

Modules

 interp_config
 Interpolator configuration.
 

Functions

void interp_claim_lane (interp_hw_t *interp, uint lane)
 Claim the interpolator lane specified. More...
 
void interp_claim_lane_mask (interp_hw_t *interp, uint lane_mask)
 Claim the interpolator lanes specified in the mask. More...
 
void interp_unclaim_lane (interp_hw_t *interp, uint lane)
 Release a previously claimed interpolator lane. More...
 
bool interp_lane_is_claimed (interp_hw_t *interp, uint lane)
 Determine if an interpolator lane is claimed. More...
 
void interp_unclaim_lane_mask (interp_hw_t *interp, uint lane_mask)
 Release previously claimed interpolator lanes. More...
 
static void interp_set_force_bits (interp_hw_t *interp, uint lane, uint bits)
 Directly set the force bits on a specified lane. More...
 
void interp_save (interp_hw_t *interp, interp_hw_save_t *saver)
 Save the specified interpolator state. More...
 
void interp_restore (interp_hw_t *interp, interp_hw_save_t *saver)
 Restore an interpolator state. More...
 
static void interp_set_base (interp_hw_t *interp, uint lane, uint32_t val)
 Sets the interpolator base register by lane. More...
 
static uint32_t interp_get_base (interp_hw_t *interp, uint lane)
 Gets the content of interpolator base register by lane. More...
 
static void interp_set_base_both (interp_hw_t *interp, uint32_t val)
 Sets the interpolator base registers simultaneously. More...
 
static void interp_set_accumulator (interp_hw_t *interp, uint lane, uint32_t val)
 Sets the interpolator accumulator register by lane. More...
 
static uint32_t interp_get_accumulator (interp_hw_t *interp, uint lane)
 Gets the content of the interpolator accumulator register by lane. More...
 
static uint32_t interp_pop_lane_result (interp_hw_t *interp, uint lane)
 Read lane result, and write lane results to both accumulators to update the interpolator. More...
 
static uint32_t interp_peek_lane_result (interp_hw_t *interp, uint lane)
 Read lane result. More...
 
static uint32_t interp_pop_full_result (interp_hw_t *interp)
 Read lane result, and write lane results to both accumulators to update the interpolator. More...
 
static uint32_t interp_peek_full_result (interp_hw_t *interp)
 Read lane result. More...
 
static void interp_add_accumulater (interp_hw_t *interp, uint lane, uint32_t val)
 Add to accumulator. More...
 
static uint32_t interp_get_raw (interp_hw_t *interp, uint lane)
 Get raw lane value. More...
 

Detailed Description

Hardware Interpolator API

Each core is equipped with two interpolators (INTERP0 and INTERP1) which can be used to accelerate tasks by combining certain pre-configured simple operations into a single processor cycle. Intended for cases where the pre-configured operation is repeated a large number of times, this results in code which uses both fewer CPU cycles and fewer CPU registers in the time critical sections of the code.

The interpolators are used heavily to accelerate audio operations within the SDK, but their flexible configuration make it possible to optimise many other tasks such as quantization and dithering, table lookup address generation, affine texture mapping, decompression and linear feedback.

Please refer to the RP2040 datasheet for more information on the HW interpolators and how they work.

Function Documentation

◆ interp_add_accumulater()

static void interp_add_accumulater ( interp_hw_t interp,
uint  lane,
uint32_t  val 
)
inlinestatic

Add to accumulator.

Atomically add the specified value to the accumulator on the specified lane

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1
valValue to add
Returns
The content of the FULL register

◆ interp_claim_lane()

void interp_claim_lane ( interp_hw_t interp,
uint  lane 
)

Claim the interpolator lane specified.

Use this function to claim exclusive access to the specified interpolator lane.

This function will panic if the lane is already claimed.

Parameters
interpInterpolator on which to claim a lane. interp0 or interp1
laneThe lane number, 0 or 1.

◆ interp_claim_lane_mask()

void interp_claim_lane_mask ( interp_hw_t interp,
uint  lane_mask 
)

Claim the interpolator lanes specified in the mask.

Parameters
interpInterpolator on which to claim lanes. interp0 or interp1
lane_maskBit pattern of lanes to claim (only bits 0 and 1 are valid)

◆ interp_get_accumulator()

static uint32_t interp_get_accumulator ( interp_hw_t interp,
uint  lane 
)
inlinestatic

Gets the content of the interpolator accumulator register by lane.

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1
Returns
The current content of the register

◆ interp_get_base()

static uint32_t interp_get_base ( interp_hw_t interp,
uint  lane 
)
inlinestatic

Gets the content of interpolator base register by lane.

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1 or 2
Returns
The current content of the lane base register

◆ interp_get_raw()

static uint32_t interp_get_raw ( interp_hw_t interp,
uint  lane 
)
inlinestatic

Get raw lane value.

Returns the raw shift and mask value from the specified lane, BASE0 is NOT added

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1
Returns
The raw shift/mask value

◆ interp_lane_is_claimed()

bool interp_lane_is_claimed ( interp_hw_t interp,
uint  lane 
)

Determine if an interpolator lane is claimed.

Parameters
interpInterpolator whose lane to check
laneThe lane number, 0 or 1
Returns
true if claimed, false otherwise
See also
interp_claim_lane
interp_claim_lane_mask

◆ interp_peek_full_result()

static uint32_t interp_peek_full_result ( interp_hw_t interp)
inlinestatic

Read lane result.

Parameters
interpInterpolator instance, interp0 or interp1.
Returns
The content of the FULL register

◆ interp_peek_lane_result()

static uint32_t interp_peek_lane_result ( interp_hw_t interp,
uint  lane 
)
inlinestatic

Read lane result.

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1
Returns
The content of the lane result register

◆ interp_pop_full_result()

static uint32_t interp_pop_full_result ( interp_hw_t interp)
inlinestatic

Read lane result, and write lane results to both accumulators to update the interpolator.

Parameters
interpInterpolator instance, interp0 or interp1.
Returns
The content of the FULL register

◆ interp_pop_lane_result()

static uint32_t interp_pop_lane_result ( interp_hw_t interp,
uint  lane 
)
inlinestatic

Read lane result, and write lane results to both accumulators to update the interpolator.

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1
Returns
The content of the lane result register

◆ interp_restore()

void interp_restore ( interp_hw_t interp,
interp_hw_save_t saver 
)

Restore an interpolator state.

Parameters
interpInterpolator instance, interp0 or interp1.
saverPointer to save structure to reapply to the specified interpolator

◆ interp_save()

void interp_save ( interp_hw_t interp,
interp_hw_save_t saver 
)

Save the specified interpolator state.

Can be used to save state if you need an interpolator for another purpose, state can then be recovered afterwards and continue from that point

Parameters
interpInterpolator instance, interp0 or interp1.
saverPointer to the save structure to fill in

◆ interp_set_accumulator()

static void interp_set_accumulator ( interp_hw_t interp,
uint  lane,
uint32_t  val 
)
inlinestatic

Sets the interpolator accumulator register by lane.

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1
valThe value to apply to the register

◆ interp_set_base()

static void interp_set_base ( interp_hw_t interp,
uint  lane,
uint32_t  val 
)
inlinestatic

Sets the interpolator base register by lane.

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane number, 0 or 1 or 2
valThe value to apply to the register

◆ interp_set_base_both()

static void interp_set_base_both ( interp_hw_t interp,
uint32_t  val 
)
inlinestatic

Sets the interpolator base registers simultaneously.

The lower 16 bits go to BASE0, upper bits to BASE1 simultaneously. Each half is sign-extended to 32 bits if that lane’s SIGNED flag is set.

Parameters
interpInterpolator instance, interp0 or interp1.
valThe value to apply to the register

◆ interp_set_force_bits()

static void interp_set_force_bits ( interp_hw_t interp,
uint  lane,
uint  bits 
)
inlinestatic

Directly set the force bits on a specified lane.

These bits are ORed into bits 29:28 of the lane result presented to the processor on the bus. There is no effect on the internal 32-bit datapath.

Useful for using a lane to generate sequence of pointers into flash or SRAM, saving a subsequent OR or add operation.

Parameters
interpInterpolator instance, interp0 or interp1.
laneThe lane to set
bitsThe bits to set (bits 0 and 1, value range 0-3)

◆ interp_unclaim_lane()

void interp_unclaim_lane ( interp_hw_t interp,
uint  lane 
)

Release a previously claimed interpolator lane.

Parameters
interpInterpolator on which to release a lane. interp0 or interp1
laneThe lane number, 0 or 1

◆ interp_unclaim_lane_mask()

void interp_unclaim_lane_mask ( interp_hw_t interp,
uint  lane_mask 
)

Release previously claimed interpolator lanes.

See also
interp_claim_lane_mask
Parameters
interpInterpolator on which to release lanes. interp0 or interp1
lane_maskBit pattern of lanes to unclaim (only bits 0 and 1 are valid)