MMDVSQ: Memory-Mapped Divide and Square Root

Overview

The MCUXpresso SDK provides driver for the Memory-Mapped Divide and Square Root (MMDVSQ) module of MCUXpresso SDK devices.

ARM processor cores in the Cortex-M family implementing the ARMv6-M instruction set architecture do not include hardware support for integer division operations. However, in certain deeply-embedded application spaces, hardware support for this class of arithmetic operations along with an unsigned square root function is important to maximize the system performance and minimize the device power dissipation. Accordingly, the MMDVSQ module is included to serve as a memory-mapped co-processor located in a special address space within the system memory map accessible only to the processor core. The MMDVSQ module supports execution of the integer division operations defined in the ARMv7-M instruction set architecture plus an unsigned integer square root operation. The supported integer division operations include 32/32 signed (SDIV) and unsigned (UDIV) calculations.

Function groups

MMDVSQ functional Operation

This group implements the MMDVSQ functional API.

MMDVSQ status Operation

This group implements the MMDVSQ status API.

Typical use case and example

Example: Refer to the driver examples codes located at <SDK_ROOT>/boards/<BOARD>/driver_examples/mmdvsq

Typedefs
typedef enum _mmdvsq_execution_status	mmdvsq_execution_status_t
	MMDVSQ execution status.
typedef enum _mmdvsq_fast_start_select	mmdvsq_fast_start_select_t
	MMDVSQ divide fast start select.

Enumerations
enum	_mmdvsq_execution_status {   kMMDVSQ_IdleSquareRoot = 0x01U,   kMMDVSQ_IdleDivide = 0x02U,   kMMDVSQ_BusySquareRoot = 0x05U,   kMMDVSQ_BusyDivide = 0x06U }
	MMDVSQ execution status. More...
enum	_mmdvsq_fast_start_select {   kMMDVSQ_EnableFastStart = 0U,   kMMDVSQ_DisableFastStart }
	MMDVSQ divide fast start select. More...

Driver version
#define	FSL_MMSVSQ_DRIVER_VERSION   (MAKE_VERSION(2, 0, 3))
	Version 2.0.3. More...

MMDVSQ functional Operation
int32_t	MMDVSQ_GetDivideRemainder (MMDVSQ_Type *base, int32_t dividend, int32_t divisor, bool isUnsigned)
	Performs the MMDVSQ division operation and returns the remainder. More...
int32_t	MMDVSQ_GetDivideQuotient (MMDVSQ_Type *base, int32_t dividend, int32_t divisor, bool isUnsigned)
	Performs the MMDVSQ division operation and returns the quotient. More...
uint16_t	MMDVSQ_Sqrt (MMDVSQ_Type *base, uint32_t radicand)
	Performs the MMDVSQ square root operation. More...

MMDVSQ status Operation
static mmdvsq_execution_status_t	MMDVSQ_GetExecutionStatus (MMDVSQ_Type *base)
	Gets the MMDVSQ execution status. More...
static void	MMDVSQ_SetFastStartConfig (MMDVSQ_Type *base, mmdvsq_fast_start_select_t mode)
	Configures MMDVSQ fast start mode. More...
static void	MMDVSQ_SetDivideByZeroConfig (MMDVSQ_Type *base, bool isDivByZero)
	Configures the MMDVSQ divide-by-zero mode. More...

Macro Definition Documentation

#define FSL_MMSVSQ_DRIVER_VERSION   (MAKE_VERSION(2, 0, 3))

Enumeration Type Documentation

enum _mmdvsq_execution_status

Enumerator
kMMDVSQ_IdleSquareRoot	MMDVSQ is idle; the last calculation was a square root.
kMMDVSQ_IdleDivide	MMDVSQ is idle; the last calculation was division.
kMMDVSQ_BusySquareRoot	MMDVSQ is busy processing a square root calculation.
kMMDVSQ_BusyDivide	MMDVSQ is busy processing a division calculation.

enum _mmdvsq_fast_start_select

Enumerator
kMMDVSQ_EnableFastStart	Division operation is initiated by a write to the DSOR register.
kMMDVSQ_DisableFastStart	Division operation is initiated by a write to CSR[SRT] = 1; normal start instead fast start.

Function Documentation

int32_t MMDVSQ_GetDivideRemainder	(	MMDVSQ_Type *	base,
		int32_t	dividend,
		int32_t	divisor,
		bool	isUnsigned
	)

Parameters

base	MMDVSQ peripheral address
dividend	Dividend value
divisor	Divisor value
isUnsigned	Mode of unsigned divide true unsigned divide false signed divide

int32_t MMDVSQ_GetDivideQuotient	(	MMDVSQ_Type *	base,
		int32_t	dividend,
		int32_t	divisor,
		bool	isUnsigned
	)

Parameters

base	MMDVSQ peripheral address
dividend	Dividend value
divisor	Divisor value
isUnsigned	Mode of unsigned divide true unsigned divide false signed divide

uint16_t MMDVSQ_Sqrt	(	MMDVSQ_Type *	base,
		uint32_t	radicand
	)

This function performs the MMDVSQ square root operation and returns the square root result of a given radicand value.

Parameters

base	MMDVSQ peripheral address
radicand	Radicand value

static mmdvsq_execution_status_t MMDVSQ_GetExecutionStatus ( MMDVSQ_Type *  base )

inlinestatic

This function checks the current MMDVSQ execution status of the combined CSR[BUSY, DIV, SQRT] indicators.

Parameters

base	MMDVSQ peripheral address

Returns

Current MMDVSQ execution status

static void MMDVSQ_SetFastStartConfig ( MMDVSQ_Type *  base, mmdvsq_fast_start_select_t  mode  )

inlinestatic

This function sets the MMDVSQ division fast start. The MMDVSQ supports two mechanisms for initiating a division operation. The default mechanism is a “fast start” where a write to the DSOR register begins the division. Alternatively, the start mechanism can begin after a write to the CSR register with CSR[SRT] set.

Parameters

base	MMDVSQ peripheral address
mode	Mode of Divide-Fast-Start kMmdvsqDivideFastStart = 0 kMmdvsqDivideNormalStart = 1

static void MMDVSQ_SetDivideByZeroConfig ( MMDVSQ_Type *  base, bool  isDivByZero  )

inlinestatic

This function configures the MMDVSQ response to divide-by-zero calculations. If both CSR[DZ] and CSR[DZE] are set, then a subsequent read of the RES register is error-terminated to signal the processor of the attempted divide-by-zero. Otherwise, the register contents are returned.

Parameters

base	MMDVSQ peripheral address
isDivByZero	Mode of Divide-By-Zero kMmdvsqDivideByZeroDis = 0 kMmdvsqDivideByZeroEn = 1