Detailed Description

Author: Kaspar Schleiser kaspa.nosp@m.r@sc.nosp@m.hleis.nosp@m.er.d.nosp@m.e; Joakim Nohlgård joaki.nosp@m.m.no.nosp@m.hlgar.nosp@m.d@ei.nosp@m.stec..nosp@m.se

Definition in file div.h.

#include <assert.h>
#include <stdint.h>

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#define	DIV_H_INV_15625_32 0x431bde83ul
	Approximation of (2**l)/d for d=15625, l=12, 32 bits.

#define	DIV_H_INV_15625_64 0x431bde82d7b634dbull
	Approximation of (2**l)/d for d=15625, l=12, 64 bits.

#define	DIV_H_INV_15625_SHIFT 12
	Required shifts for division by 15625, l above.

uint64_t	_div_mulhi64 (const uint64_t a, const uint64_t b)

static uint64_t	div_u64_by_15625 (uint64_t val)
	Integer divide val by 15625, 64 bit version.

static uint32_t	div_u64_by_125 (uint64_t val)
	Integer divide val by 125.

static uint64_t	div_u64_by_1000000 (uint64_t val)
	Integer divide val by 1000000.

static uint32_t	div_u32_by_15625div512 (uint32_t val)
	Divide val by (15625/512)

static uint64_t	div_u64_by_15625div512 (uint64_t val)
	Divide val by (15625/512)

static uint32_t	div_u32_by_44488 (uint32_t val)
	Integer divide val by 44488.

static uint32_t	div_u32_mod_44488 (uint32_t val)
	Modulo 44488.

Macro Definition Documentation

◆ DIV_H_INV_15625_32

#define DIV_H_INV_15625_32 0x431bde83ul

Approximation of (2**l)/d for d=15625, l=12, 32 bits.

Definition at line 37 of file div.h.

◆ DIV_H_INV_15625_64

#define DIV_H_INV_15625_64 0x431bde82d7b634dbull

Approximation of (2**l)/d for d=15625, l=12, 64 bits.

Definition at line 42 of file div.h.

◆ DIV_H_INV_15625_SHIFT

#define DIV_H_INV_15625_SHIFT 12

Required shifts for division by 15625, l above.

Definition at line 47 of file div.h.

Function Documentation

◆ div_u32_by_15625div512()

static uint32_t div_u32_by_15625div512 ( uint32_t val )

inlinestatic

Divide val by (15625/512)

This is used to quantize a 1MHz value to the closest 32768Hz value, e.g., for timers.

The algorithm uses the modular multiplicative inverse of 15625 to use only multiplication and bit shifts to perform the division.

The result will be equal to the mathematical expression: floor((val * 512) / 15625)

Parameters

[in] val dividend

Returns: (val / (15625/512))

Definition at line 130 of file div.h.

◆ div_u32_by_44488()

static uint32_t div_u32_by_44488 ( uint32_t val )

inlinestatic

Integer divide val by 44488.

Parameters

[in] val dividend

Returns: (val / 44488)

Definition at line 164 of file div.h.

◆ div_u32_mod_44488()

static uint32_t div_u32_mod_44488 ( uint32_t val )

inlinestatic

Modulo 44488.

Parameters

[in] val dividend

Returns: (val % 44488)

Definition at line 175 of file div.h.

◆ div_u64_by_1000000()

static uint64_t div_u64_by_1000000 ( uint64_t val )

inlinestatic

Integer divide val by 1000000.

Parameters

[in] val dividend

Returns: (val / 1000000)

Definition at line 111 of file div.h.

◆ div_u64_by_125()

static uint32_t div_u64_by_125 ( uint64_t val )

inlinestatic

Integer divide val by 125.

This function can be used to convert uint64_t microsecond times (or intervals) to milliseconds and store them in uint32_t variables, with up to ~50 days worth of milliseconds ((2**32*1000) -1). Use e.g., ms = div_u64_by_125(microseconds >> 3)

Precondition: val <= 536870911999 ((2**32 * 125) -1)

Parameters

[in] val dividend

Returns: (val / 125)

Definition at line 91 of file div.h.

◆ div_u64_by_15625()

static uint64_t div_u64_by_15625 ( uint64_t val )

inlinestatic

Integer divide val by 15625, 64 bit version.

Parameters

[in] val dividend

Returns: (val / 15625)

Definition at line 70 of file div.h.

◆ div_u64_by_15625div512()

static uint64_t div_u64_by_15625div512 ( uint64_t val )

inlinestatic

Divide val by (15625/512)

This is used to quantize a 1MHz value to the closest 32768Hz value, e.g., for timers.

Parameters

[in] val dividend

Returns: (val / (15625/512))

Definition at line 144 of file div.h.