Raspberry Pi /RP2350 /SIO /INTERP1_CTRL_LANE0

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Interpret as INTERP1_CTRL_LANE0

31 2827 2423 2019 1615 1211 87 43 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0SHIFT0MASK_LSB0MASK_MSB0 (SIGNED)SIGNED 0 (CROSS_INPUT)CROSS_INPUT 0 (CROSS_RESULT)CROSS_RESULT 0 (ADD_RAW)ADD_RAW 0FORCE_MSB 0 (CLAMP)CLAMP 0 (OVERF0)OVERF0 0 (OVERF1)OVERF1 0 (OVERF)OVERF

Description

Control register for lane 0

Fields

SHIFT

Right-rotate applied to accumulator before masking. By appropriately configuring the masks, left and right shifts can be synthesised.

MASK_LSB

The least-significant bit allowed to pass by the mask (inclusive)

MASK_MSB

The most-significant bit allowed to pass by the mask (inclusive) Setting MSB < LSB may cause chip to turn inside-out

SIGNED

If SIGNED is set, the shifted and masked accumulator value is sign-extended to 32 bits before adding to BASE0, and LANE0 PEEK/POP appear extended to 32 bits when read by processor.

CROSS_INPUT

If 1, feed the opposite lane’s accumulator into this lane’s shift + mask hardware. Takes effect even if ADD_RAW is set (the CROSS_INPUT mux is before the shift+mask bypass)

CROSS_RESULT

If 1, feed the opposite lane’s result into this lane’s accumulator on POP.

ADD_RAW

If 1, mask + shift is bypassed for LANE0 result. This does not affect FULL result.

FORCE_MSB

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.

CLAMP

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

  • LANE0 result is 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
OVERF0

Indicates if any masked-off MSBs in ACCUM0 are set.

OVERF1

Indicates if any masked-off MSBs in ACCUM1 are set.

OVERF

Set if either OVERF0 or OVERF1 is set.

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