CRC calculator peripheral-block model for the board emulator. More...

#include <stdint.h>
#include <stdio.h>
#include "board_periph_block.h"
#include "emu_host_io_internal.h"

Include dependency graph for board_periph_crc.c:

Data Structures
struct	crc_state_t
	CRC register state. More...

Enumerations
enum	crc_lit_t : uint32_t { k_u32_all = 0xFFFFFFFFU , k_u16_mask = 0xFFFFU , k_byte_mask = 0xFFU }
	Bit-width masks for the CRC unit model. More...
enum	crc_map_t : uint64_t { k_crc_base = 0x40310000UL , k_crc_span = 0x20UL , k_crc_off_cr0 = 0x00UL , k_crc_off_cr1 = 0x01UL , k_crc_off_dir = 0x04UL , k_crc_off_dor = 0x08UL }
	CRC block geometry (ra8_crc_regs.h). More...
enum	crc_cr0_field_t : uint32_t { k_crc_gps_mask = 0x07U , k_crc_dorclr = 0x80U }
	CRCCR0 fields (ra8_crc_regs.h). More...
enum	crc_gps_t : uint32_t { k_crc_gps_8 = 1U , k_crc_gps_16 = 2U , k_crc_gps_ccitt = 3U , k_crc_gps_32 = 4U , k_crc_gps_32c = 5U }
	GPS polynomial encodings (CRCCR0.GPS). More...
enum	crc_poly_refl_t : uint32_t { k_crc_poly_16_refl = 0x0000A001U , k_crc_poly_32_refl = 0xEDB88320U , k_crc_poly_32c_refl = 0x82F63B78U }
	Reflected (LSB-first) polynomials for the reflected GPS modes. More...
enum	crc_poly_fwd_t : uint32_t { k_crc_poly_8_fwd = 0x00000007U , k_crc_poly_ccitt_fwd = 0x00001021U }
	MSB-first polynomials for the non-reflected GPS modes. More...
enum	crc_order_t : uint32_t { k_crc_block_order = 140U }
	Per-tick order slot for the CRC block (relative order only). More...

Functions
static RA8_INTERNAL uint32_t	internal_crc_step_reflected (uint32_t crc, uint8_t byte, uint32_t poly)
	Fold one byte into a reflected (LSB-first) CRC of any width.
static RA8_INTERNAL uint32_t	internal_crc_step_forward (uint32_t crc, uint8_t byte, uint32_t poly, uint32_t width)
	Fold one byte into an MSB-first CRC of `width` bits.
static RA8_INTERNAL void	internal_crc_fold_byte (uint8_t byte)
	Fold one input byte into CRCDOR using the CRCCR0.GPS polynomial.
static RA8_INTERNAL void	internal_crc_reset (void)
	Reset the CRC unit to power-on state.
static RA8_INTERNAL uint64_t	internal_crc_read (uc_engine *uc, uint64_t addr, unsigned size)
	MMIO read inside the CRC window.
static RA8_INTERNAL void	internal_crc_write (uc_engine *uc, uint64_t addr, unsigned size, uint64_t value)
	MMIO write inside the CRC window.
static RA8_INTERNAL void	internal_crc_report (void)
	End-of-run CRC section: last result + bytes folded.
static RA8_INTERNAL void	internal_crc_block_register (void)
	Register the CRC block before main (host constructor).

Variables
static crc_state_t	s_crc
static const board_periph_block_t	s_k_crc_block
	CRC block descriptor (self-registered with the core).

Detailed Description

CRC calculator peripheral-block model for the board emulator.

Models the RA8D2 CRC unit (ra8_crc_regs.h, ra8_crc.c) at 0x40310000 so crc_demo's hardware CRC matches its software reference (it printed "crc: hw=00000000 ... match=N" against the sparse fallback, which returned a constant 0). The unit is a single running-remainder register CRCDOR fed one byte at a time through CRCDIR; this model reproduces that:

CRCDIR (+0x04, write): each byte of the written value is folded into CRCDOR with the polynomial CRCCR0.GPS selects. A 32-bit access (CRC-32 / CRC-32C) folds four bytes LSB-first – the order ra8_crc's word feed produces – and an 8-bit access (CRC-8 / 16 / CCITT) folds one byte.
CRCDOR (+0x08, read/write): the running remainder. Writable so the driver can pre-seed it (CRC-32 / 32C seed 0xFFFFFFFF and XOR the readback in software; the hardware applies neither). CRCCR0.DORCLR clears it.
CRCCR0 (+0x00): GPS[2:0] polynomial select, LMS bit-order, DORCLR.

Reflection follows the RA8D2 polynomial definitions: CRC-32 / CRC-32C and the reflected CRC-16 fold LSB-first; CRC-8 and CRC-CCITT fold MSB-first. Only the CRC-32 path is exercised by an in-tree example (crc_demo, where it now reads match=Y); the others use their standard parameters.

Copyright: Copyright (c) 2026 Brighton Sikarskie SPDX-License-Identifier: MIT

Since: 0.1.0

Definition in file board_periph_crc.c.

Enumeration Type Documentation

◆ crc_cr0_field_t

enum crc_cr0_field_t : uint32_t

CRCCR0 fields (ra8_crc_regs.h).

Enumerator
k_crc_gps_mask	GPS[2:0] polynomial select.
k_crc_dorclr	DORCLR: clear CRCDOR (bit 7).

Definition at line 55 of file board_periph_crc.c.

◆ crc_gps_t

enum crc_gps_t : uint32_t

GPS polynomial encodings (CRCCR0.GPS).

Enumerator
k_crc_gps_8	CRC-8 (X^8+X^2+X+1).
k_crc_gps_16	CRC-16 (X^16+X^15+X^2+1).
k_crc_gps_ccitt	CRC-CCITT (X^16+X^12+X^5+1).
k_crc_gps_32	CRC-32 (IEEE 802.3).
k_crc_gps_32c	CRC-32C (Castagnoli).

Definition at line 61 of file board_periph_crc.c.

◆ crc_lit_t

enum crc_lit_t : uint32_t

Bit-width masks for the CRC unit model.

Enumerator
k_u32_all	32-bit all-ones.
k_u16_mask	16-bit mask.
k_byte_mask	8-bit mask.

Definition at line 38 of file board_periph_crc.c.

◆ crc_map_t

enum crc_map_t : uint64_t

CRC block geometry (ra8_crc_regs.h).

Enumerator
k_crc_base	CRC base (HUM Ch 48).
k_crc_span	Register window.
k_crc_off_cr0	CRCCR0 (GPS/LMS/DORCLR), 8b.
k_crc_off_cr1	CRCCR1 (snoop), 8b.
k_crc_off_dir	CRCDIR / CRCDIR_BY data in.
k_crc_off_dor	CRCDOR result (32b).

Definition at line 45 of file board_periph_crc.c.

◆ crc_order_t

enum crc_order_t : uint32_t

Per-tick order slot for the CRC block (relative order only).

Enumerator
k_crc_block_order	After the existing blocks; report order.

Definition at line 83 of file board_periph_crc.c.

◆ crc_poly_fwd_t

enum crc_poly_fwd_t : uint32_t

MSB-first polynomials for the non-reflected GPS modes.

Enumerator
k_crc_poly_8_fwd	CRC-8 X^8+X^2+X+1.
k_crc_poly_ccitt_fwd	CRC-CCITT.

Definition at line 77 of file board_periph_crc.c.

◆ crc_poly_refl_t

enum crc_poly_refl_t : uint32_t

Reflected (LSB-first) polynomials for the reflected GPS modes.

Enumerator
k_crc_poly_16_refl	Reflected 0x8005.
k_crc_poly_32_refl	Reflected 0x04C11DB7.
k_crc_poly_32c_refl	Reflected 0x1EDC6F41.

Definition at line 70 of file board_periph_crc.c.

Function Documentation

◆ internal_crc_block_register()

RA8_INTERNAL void internal_crc_block_register ( void )

static

Register the CRC block before main (host constructor).

Definition at line 318 of file board_periph_crc.c.

References board_periph_register_block(), RA8_INTERNAL, and s_k_crc_block.

◆ internal_crc_fold_byte()

RA8_INTERNAL void internal_crc_fold_byte ( uint8_t byte )

static

Fold one input byte into CRCDOR using the CRCCR0.GPS polynomial.

Fold one input byte into crcdor using the crccr0.gps polynomial; this step is contained within the board periph CRC model and uses bounded caller or module-owned storage.

Parameters

[in] byte One data byte received from or sent to the emulated interface.

Precondition: Arguments satisfy the ranges documented for CRC fold byte.; The call executes on the emulator's single owning thread.

Postcondition: State changes remain confined to the board periph CRC model and documented output objects.; Ownership of caller-supplied storage is unchanged.

Note: The operation is synchronous and does not transfer heap ownership.

Since: 0.1.0

Definition at line 158 of file board_periph_crc.c.

References internal_crc_step_forward(), internal_crc_step_reflected(), k_crc_gps_16, k_crc_gps_32, k_crc_gps_32c, k_crc_gps_8, k_crc_gps_ccitt, k_crc_gps_mask, k_crc_poly_16_refl, k_crc_poly_32_refl, k_crc_poly_32c_refl, k_crc_poly_8_fwd, k_crc_poly_ccitt_fwd, RA8_INTERNAL, and s_crc.

Referenced by internal_crc_write().

◆ internal_crc_read()

RA8_INTERNAL uint64_t internal_crc_read	(	uc_engine *	uc,
		uint64_t	addr,
		unsigned	size )

static

MMIO read inside the CRC window.

MMIO read inside the crc window; this step is contained within the board periph CRC model and uses bounded caller or module-owned storage.

Parameters

[in,out]	uc	Unicorn engine whose emulated state is read or updated.
[in]	addr	Guest address involved in the operation.
[in]	size	Size of the requested region or access in bytes.

Returns: The CRC read result produced by the board periph CRC model.

Return values

value The operation-specific CRC read value.

Precondition: Arguments satisfy the ranges documented for CRC read.; The call executes on the emulator's single owning thread.

Postcondition: State changes remain confined to the board periph CRC model and documented output objects.; Ownership of caller-supplied storage is unchanged.

Note: The operation is synchronous and does not transfer heap ownership.

Since: 0.1.0

Definition at line 211 of file board_periph_crc.c.

References k_crc_base, k_crc_off_cr0, k_crc_off_cr1, k_crc_off_dor, RA8_INTERNAL, and s_crc.

◆ internal_crc_report()

RA8_INTERNAL void internal_crc_report ( void )

static

End-of-run CRC section: last result + bytes folded.

End-of-run crc section: last result + bytes folded; this step is contained within the board periph CRC model and uses bounded caller or module-owned storage.

Precondition: Arguments satisfy the ranges documented for CRC report.; The call executes on the emulator's single owning thread.

Postcondition: State changes remain confined to the board periph CRC model and documented output objects.; Ownership of caller-supplied storage is unchanged.

Note: The operation is synchronous and does not transfer heap ownership.

Since: 0.1.0

Definition at line 293 of file board_periph_crc.c.

References k_crc_gps_mask, priv_emu_io_errf(), RA8_INTERNAL, and s_crc.

◆ internal_crc_reset()

RA8_INTERNAL void internal_crc_reset ( void )

static

Reset the CRC unit to power-on state.

Reset the crc unit to power-on state; this step is contained within the board periph CRC model and uses bounded caller or module-owned storage.

Precondition: Arguments satisfy the ranges documented for CRC reset.; The call executes on the emulator's single owning thread.

Postcondition: State changes remain confined to the board periph CRC model and documented output objects.; Ownership of caller-supplied storage is unchanged.

Note: The operation is synchronous and does not transfer heap ownership.

Since: 0.1.0

Definition at line 190 of file board_periph_crc.c.

References RA8_INTERNAL, and s_crc.

◆ internal_crc_step_forward()

RA8_INTERNAL uint32_t internal_crc_step_forward	(	uint32_t	crc,
		uint8_t	byte,
		uint32_t	poly,
		uint32_t	width )

static

Fold one byte into an MSB-first CRC of width bits.

Fold one byte into an msb-first crc of width bits; this step is contained within the board periph CRC model and uses bounded caller or module-owned storage.

Parameters

[in]	crc	Crc input used by the operation.
[in]	byte	One data byte received from or sent to the emulated interface.
[in]	poly	Poly input used by the operation.
[in]	width	Width of the affected region in pixels.

Returns: The CRC step forward result produced by the board periph CRC model.

Return values

value The operation-specific CRC step forward value.

Precondition: Arguments satisfy the ranges documented for CRC step forward.; The call executes on the emulator's single owning thread.

Postcondition: State changes remain confined to the board periph CRC model and documented output objects.; Ownership of caller-supplied storage is unchanged.

Note: The operation is synchronous and does not transfer heap ownership.

Since: 0.1.0

Definition at line 134 of file board_periph_crc.c.

References k_u32_all.

Referenced by internal_crc_fold_byte().

◆ internal_crc_step_reflected()

RA8_INTERNAL uint32_t internal_crc_step_reflected	(	uint32_t	crc,
		uint8_t	byte,
		uint32_t	poly )

static

Fold one byte into a reflected (LSB-first) CRC of any width.

Fold one byte into a reflected (lsb-first) crc of any width; this step is contained within the board periph CRC model and uses bounded caller or module-owned storage.

Parameters

[in]	crc	Crc input used by the operation.
[in]	byte	One data byte received from or sent to the emulated interface.
[in]	poly	Poly input used by the operation.

Returns: The CRC step reflected result produced by the board periph CRC model.

Return values

value The operation-specific CRC step reflected value.

Precondition: Arguments satisfy the ranges documented for CRC step reflected.; The call executes on the emulator's single owning thread.

Postcondition: State changes remain confined to the board periph CRC model and documented output objects.; Ownership of caller-supplied storage is unchanged.

Note: The operation is synchronous and does not transfer heap ownership.

Since: 0.1.0

Definition at line 110 of file board_periph_crc.c.

References RA8_INTERNAL.

Referenced by internal_crc_fold_byte().

◆ internal_crc_write()

RA8_INTERNAL void internal_crc_write	(	uc_engine *	uc,
		uint64_t	addr,
		unsigned	size,
		uint64_t	value )

static

MMIO write inside the CRC window.

MMIO write inside the crc window; this step is contained within the board periph CRC model and uses bounded caller or module-owned storage.

Parameters

[in,out]	uc	Unicorn engine whose emulated state is read or updated.
[in]	addr	Guest address involved in the operation.
[in]	size	Size of the requested region or access in bytes.
[in]	value	Register or payload value involved in the operation.

Precondition: Arguments satisfy the ranges documented for CRC write.; The call executes on the emulator's single owning thread.

Postcondition: State changes remain confined to the board periph CRC model and documented output objects.; Ownership of caller-supplied storage is unchanged.

Note: The operation is synchronous and does not transfer heap ownership.

Since: 0.1.0

Definition at line 243 of file board_periph_crc.c.

References internal_crc_fold_byte(), k_byte_mask, k_crc_base, k_crc_dorclr, k_crc_off_cr0, k_crc_off_cr1, k_crc_off_dir, k_crc_off_dor, k_u16_mask, and s_crc.

Variable Documentation

◆ s_crc

crc_state_t s_crc

static

Definition at line 95 of file board_periph_crc.c.

Referenced by internal_crc_fold_byte(), internal_crc_read(), internal_crc_report(), internal_crc_reset(), and internal_crc_write().

◆ s_k_crc_block

const board_periph_block_t s_k_crc_block

static

Initial value:

                                                = {
  .base   = (uint32_t)k_crc_base,
  .span   = (uint32_t)k_crc_span,
  .order  = (uint32_t)k_crc_block_order,
  .read   = internal_crc_read,
  .write  = internal_crc_write,
  .tick   = nullptr,
  .reset  = internal_crc_reset,
  .report = internal_crc_report,
  .name   = "CRC",
}

CRC block descriptor (self-registered with the core).

Definition at line 305 of file board_periph_crc.c.

Referenced by internal_crc_block_register().

Data Structures

Enumerations

Functions

Variables

Detailed Description

Enumeration Type Documentation

◆ crc_cr0_field_t

◆ crc_gps_t

◆ crc_lit_t

◆ crc_map_t

◆ crc_order_t

◆ crc_poly_fwd_t

◆ crc_poly_refl_t

Function Documentation

◆ internal_crc_block_register()

◆ internal_crc_fold_byte()

◆ internal_crc_read()

◆ internal_crc_report()

◆ internal_crc_reset()

◆ internal_crc_step_forward()

◆ internal_crc_step_reflected()

◆ internal_crc_write()

Variable Documentation

◆ s_crc

◆ s_k_crc_block