interp_config

Interpolator configuration. More...

Data Structures
struct	interp_config
	Holds the configuration for an interpolator lane. More...

Functions
static void	interp_config_set_shift (interp_config *c, uint shift)
	Set the interpolator shift value.
static void	interp_config_set_mask (interp_config *c, uint mask_lsb, uint mask_msb)
	Set the interpolator mask range.
static void	interp_config_set_cross_input (interp_config *c, bool cross_input)
	Enable cross input.
static void	interp_config_set_cross_result (interp_config *c, bool cross_result)
	Enable cross results.
static void	interp_config_set_signed (interp_config *c, bool _signed)
	Set sign extension.
static void	interp_config_set_add_raw (interp_config *c, bool add_raw)
	Set raw add option.
static void	interp_config_set_blend (interp_config *c, bool blend)
	Set blend mode.
static void	interp_config_set_clamp (interp_config *c, bool clamp)
	Set interpolator clamp mode (Interpolator 1 only).
static void	interp_config_set_force_bits (interp_config *c, uint bits)
	Set interpolator Force bits.
static interp_config	interp_default_config (void)
	Get a default configuration.
static void	interp_set_config (interp_hw_t *interp, uint lane, interp_config *config)
	Send configuration to a lane.

Detailed Description

Interpolator configuration.

Each interpolator needs to be configured, these functions provide handy helpers to set up configuration structures.

Function Documentation

interp_config_set_add_raw()

void interp_config_set_add_raw ( interp_config * c, bool add_raw )

inlinestatic

Set raw add option.

When enabled, mask + shift is bypassed for LANE0 result. This does not affect the FULL result.

Parameters

c	Pointer to interpolation config
add_raw	If true, enable raw add option.

interp_config_set_blend()

void interp_config_set_blend ( interp_config * c, bool blend )

inlinestatic

Set blend mode.

If enabled, LANE1 result is a linear interpolation between BASE0 and BASE1, controlled by the 8 LSBs of lane 1 shift and mask value (a fractional number between 0 and 255/256ths)

LANE0 result does not have BASE0 added (yields only the 8 LSBs of lane 1 shift+mask value)

FULL result does not have lane 1 shift+mask value added (BASE2 + lane 0 shift+mask)

LANE1 SIGNED flag controls whether the interpolation is signed or unsig

Parameters

c	Pointer to interpolation config
blend	Set true to enable blend mode.

interp_config_set_clamp()

void interp_config_set_clamp ( interp_config * c, bool clamp )

inlinestatic

Set interpolator clamp mode (Interpolator 1 only).

Only present on INTERP1 on each core. If CLAMP mode is enabled:

• LANE0 result is a shifted and masked ACCUM0, clamped by a lower bound of BASE0 and an upper bound of BASE1.
• Signedness of these comparisons is determined by LANE0_CTRL_SIGNED

Parameters

c	Pointer to interpolation config
clamp	Set true to enable clamp mode

interp_config_set_cross_input()

void interp_config_set_cross_input ( interp_config * c, bool cross_input )

inlinestatic

Enable cross input.

Allows feeding of the accumulator content from the other lane back in to this lanes shift+mask hardware. This will take effect even if the interp_config_set_add_raw option is set as the cross input mux is before the shift+mask bypass

Parameters

c	Pointer to interpolation config
cross_input	If true, enable the cross input.

interp_config_set_cross_result()

void interp_config_set_cross_result ( interp_config * c, bool cross_result )

inlinestatic

Enable cross results.

Allows feeding of the other lane's result into this lane's accumulator on a POP operation.

Parameters

c	Pointer to interpolation config
cross_result	If true, enables the cross result

interp_config_set_force_bits()

void interp_config_set_force_bits ( interp_config * c, uint bits )

inlinestatic

Set interpolator Force bits.

ORed into bits 29:28 of the lane result presented to the processor on the bus.

No effect on the internal 32-bit datapath. Handy for using a lane to generate sequence of pointers into flash or SRAM

Parameters

c	Pointer to interpolation config
bits	Sets the force bits to that specified. Range 0-3 (two bits)

interp_config_set_mask()

void interp_config_set_mask ( interp_config * c, uint mask_lsb, uint mask_msb )

inlinestatic

Set the interpolator mask range.

Sets the range of bits (least to most) that are allowed to pass through the interpolator

Parameters

c	Pointer to interpolation config
mask_lsb	The least significant bit allowed to pass
mask_msb	The most significant bit allowed to pass

interp_config_set_shift()

void interp_config_set_shift ( interp_config * c, uint shift )

inlinestatic

Set the interpolator shift value.

Sets the number of bits the accumulator is shifted before masking, on each iteration.

Parameters

c	Pointer to an interpolator config
shift	Number of bits

interp_config_set_signed()

void interp_config_set_signed ( interp_config * c, bool _signed )

inlinestatic

Set sign extension.

Enables signed mode, where the shifted and masked accumulator value is sign-extended to 32 bits before adding to BASE1, and LANE1 PEEK/POP results appear extended to 32 bits when read by processor.

Parameters

c	Pointer to interpolation config
_signed	If true, enables sign extension

interp_default_config()

interp_config interp_default_config ( void )

inlinestatic

Get a default configuration.

Returns

A default interpolation configuration

interp_set_config()

void interp_set_config ( interp_hw_t * interp, uint lane, interp_config * config )

inlinestatic

Send configuration to a lane.

If an invalid configuration is specified (ie a lane specific item is set on wrong lane), depending on setup this function can panic.

Parameters

interp	Interpolator instance, interp0 or interp1.
lane	The lane to set
config	Pointer to interpolation config