Routines for managing unsigned 128 bit integers. More...

#include <sc.h>

Include dependency graph for sc_uint128.h:

Data Structures
struct	sc_uint128
	An unsigned 128 bit integer represented as two uint64_t. More...

Typedefs
typedef struct sc_uint128	sc_uint128_t
	An unsigned 128 bit integer represented as two uint64_t.

Functions
int	sc_uint128_compare (const void a, const void b)
	Compare the sc_uint128_t a and the sc_uint128_t b. More...

int	sc_uint128_is_equal (const sc_uint128_t a, const sc_uint128_t b)
	Checks if the sc_uint128_t a and the sc_uint128_t b are equal. More...

void	sc_uint128_init (sc_uint128_t *a, uint64_t high, uint64_t low)
	Initializes an unsigned 128 bit integer to a given value. More...

int	sc_uint128_chk_bit (const sc_uint128_t *input, int exponent)
	Returns the bit_number-th bit of input. More...

void	sc_uint128_set_bit (sc_uint128_t *a, int exponent)
	Sets the exponent-th bit of a to one and keep all other bits. More...

void	sc_uint128_copy (const sc_uint128_t input, sc_uint128_t output)
	Copies an initialized sc_uint128_t to a sc_uint128_t. More...

void	sc_uint128_add (const sc_uint128_t a, const sc_uint128_t b, sc_uint128_t *result)
	Adds the uint128_t b to the uint128_t a. More...

void	sc_uint128_sub (const sc_uint128_t a, const sc_uint128_t b, sc_uint128_t *result)
	Subtracts the uint128_t b from the uint128_t a. More...

void	sc_uint128_bitwise_neg (const sc_uint128_t a, sc_uint128_t result)
	Calculates the bitwise negation of the uint128_t a. More...

void	sc_uint128_bitwise_or (const sc_uint128_t a, const sc_uint128_t b, sc_uint128_t *result)
	Calculates the bitwise or of the uint128_t a and b. More...

void	sc_uint128_bitwise_and (const sc_uint128_t a, const sc_uint128_t b, sc_uint128_t *result)
	Calculates the bitwise and of the uint128_t a and the uint128_t b. More...

void	sc_uint128_shift_right (const sc_uint128_t input, int shift_count, sc_uint128_t result)
	Calculates the bit right shift of uint128_t input by shift_count bits. More...

void	sc_uint128_shift_left (const sc_uint128_t input, int shift_count, sc_uint128_t result)
	Calculates the bit left shift of uint128_t input by shift_count bits. More...

void	sc_uint128_add_inplace (sc_uint128_t a, const sc_uint128_t b)
	Adds the uint128 b to the uint128_t a. More...

void	sc_uint128_sub_inplace (sc_uint128_t a, const sc_uint128_t b)
	Subtracts the uint128_t b from the uint128_t a. More...

void	sc_uint128_bitwise_or_inplace (sc_uint128_t a, const sc_uint128_t b)
	Calculates the bitwise or of the uint128_t a and the uint128_t b. More...

void	sc_uint128_bitwise_and_inplace (sc_uint128_t a, const sc_uint128_t b)
	Calculates the bitwise and of the uint128_t a and the uint128_t b. More...

Detailed Description

Routines for managing unsigned 128 bit integers.

We do this to have a portable way on systems that have no native support.

Function Documentation

◆ sc_uint128_add()

void sc_uint128_add	(	const sc_uint128_t *	a,
		const sc_uint128_t *	b,
		sc_uint128_t *	result
	)

Adds the uint128_t b to the uint128_t a.

result == a or result == b is not allowed. a == b is allowed.

Parameters

[in]	a	A pointer to a sc_uint128_t.
[in]	b	A pointer to a sc_uint128_t.
[out]	result	A pointer to a sc_uint128_t. The sum a + b will be saved in result.

◆ sc_uint128_add_inplace()

void sc_uint128_add_inplace	(	sc_uint128_t *	a,
		const sc_uint128_t *	b
	)

Adds the uint128 b to the uint128_t a.

The result is saved in a. a == b is allowed.

Parameters

[in,out]	a	A pointer to a sc_uint128_t. a will be overwritten by a + b.
[in]	b	A pointer to a sc_uint128_t.

◆ sc_uint128_bitwise_and()

void sc_uint128_bitwise_and	(	const sc_uint128_t *	a,
		const sc_uint128_t *	b,
		sc_uint128_t *	result
	)

Calculates the bitwise and of the uint128_t a and the uint128_t b.

a == result is allowed. Furthermore, a == result and/or b == result is allowed.

Parameters

[in]	a	A pointer to a sc_uint128_t.
[in]	b	A pointer to a sc_uint128_t.
[out]	result	A pointer to a sc_uint128_t. The bitwise and of a and b will be saved. in result.

◆ sc_uint128_bitwise_and_inplace()

void sc_uint128_bitwise_and_inplace	(	sc_uint128_t *	a,
		const sc_uint128_t *	b
	)

Calculates the bitwise and of the uint128_t a and the uint128_t b.

a == b is allowed.

Parameters

[in,out]	a	A pointer to a sc_uint128_t. The bitwise and will be saved in a.
[in]	b	A pointer to a sc_uint128_t.

◆ sc_uint128_bitwise_neg()

void sc_uint128_bitwise_neg	(	const sc_uint128_t *	a,
		sc_uint128_t *	result
	)

Calculates the bitwise negation of the uint128_t a.

a == result is allowed.

Parameters

[in]	a	A pointer to a sc_uint128_t.
[out]	result	A pointer to a sc_uint128_t. The bitwise negation of a will be saved in result.

◆ sc_uint128_bitwise_or()

void sc_uint128_bitwise_or	(	const sc_uint128_t *	a,
		const sc_uint128_t *	b,
		sc_uint128_t *	result
	)

Calculates the bitwise or of the uint128_t a and b.

a == result is allowed. Furthermore, a == result and/or b == result is allowed.

Parameters

[in]	a	A pointer to a sc_uint128_t.
[in]	b	A pointer to a sc_uint128_t.
[out]	result	A pointer to a sc_uint128_t. The bitwise or of a and b will be saved in result.

◆ sc_uint128_bitwise_or_inplace()

void sc_uint128_bitwise_or_inplace	(	sc_uint128_t *	a,
		const sc_uint128_t *	b
	)

Calculates the bitwise or of the uint128_t a and the uint128_t b.

a == b is allowed.

Parameters

[in,out]	a	A pointer to a sc_uint128_t. The bitwise or will be saved in a.
[in]	b	A pointer to a sc_uint128_t.

◆ sc_uint128_chk_bit()

int sc_uint128_chk_bit	(	const sc_uint128_t *	input,
		int	exponent
	)

Returns the bit_number-th bit of input.

This function checks a bit of an existing, initialized value.

Parameters

[in]	input	A pointer to a sc_uint128_t.
[in]	exponent	The bit (counted from the right hand side) that is checked by logical and. Require 0 <= bit_number < 128.

Returns: True if the checked bit is set, false if not.

◆ sc_uint128_compare()

int sc_uint128_compare	(	const void *	a,
		const void *	b
	)

Compare the sc_uint128_t a and the sc_uint128_t b.

Parameters

[in]	a	A pointer to a sc_uint128_t.
[in]	b	A pointer to a sc_uint128_t.

Returns: Returns -1 if a < b, 1 if a > b and 0 if a == b.

◆ sc_uint128_copy()

void sc_uint128_copy	(	const sc_uint128_t *	input,
		sc_uint128_t *	output
	)

Copies an initialized sc_uint128_t to a sc_uint128_t.

Parameters

[in]	input	A pointer to the sc_uint128 that is copied.
[in,out]	output	A pointer to a sc_uint128_t. The high and low bits of output will be set to the high and low bits of input, respectively.

◆ sc_uint128_init()

void sc_uint128_init	(	sc_uint128_t *	a,
		uint64_t	high,
		uint64_t	low
	)

Initializes an unsigned 128 bit integer to a given value.

Parameters

[in,out]	a	A pointer to the sc_uint128_t that will be initialized.
[in]	high	The given high bits to initialize a.
[in]	low	The given low bits to initialize a.

◆ sc_uint128_is_equal()

int sc_uint128_is_equal	(	const sc_uint128_t *	a,
		const sc_uint128_t *	b
	)

Checks if the sc_uint128_t a and the sc_uint128_t b are equal.

Parameters

[in]	a	A pointer to a sc_uint128_t.
[in]	b	A pointer to a sc_uint128_t.

Returns: Returns a true value if a and b are equal, false otherwise.

◆ sc_uint128_set_bit()

void sc_uint128_set_bit	(	sc_uint128_t *	a,
		int	exponent
	)

Sets the exponent-th bit of a to one and keep all other bits.

This function modifies an existing, initialized value.

Parameters

[in,out]	a	A pointer to a sc_uint128_t.
[in]	exponent	The bit (0-based from the rightmost bit) that is set to one by logical or. 0 <= exponent < 128.

◆ sc_uint128_shift_left()

void sc_uint128_shift_left	(	const sc_uint128_t *	input,
		int	shift_count,
		sc_uint128_t *	result
	)

Calculates the bit left shift of uint128_t input by shift_count bits.

We shift in zeros from the right. If shift_count >= 128, result is 0. All bits left from the 127th bit (counted zero based from the right hand side) drop out. input == result is allowed.

Parameters

[in]	input	A pointer to a sc_uint128_t.
[in]	shift_count	Bits to shift. shift_count >= 0.
[in,out]	result	A pointer to a sc_uint128_t. The left shifted number will be saved in result.

◆ sc_uint128_shift_right()

void sc_uint128_shift_right	(	const sc_uint128_t *	input,
		int	shift_count,
		sc_uint128_t *	result
	)

Calculates the bit right shift of uint128_t input by shift_count bits.

We shift in zeros from the left. If shift_count >= 128, result is 0. All bits right from the zeroth bit (counted from the right hand side) drop out. input == result is allowed.

Parameters

[in]	input	A pointer to a sc_uint128_t.
[in]	shift_count	Bits to shift. shift_count >= 0.
[in,out]	result	A pointer to a sc_uint128_t. The right shifted number will be saved in result.

◆ sc_uint128_sub()

void sc_uint128_sub	(	const sc_uint128_t *	a,
		const sc_uint128_t *	b,
		sc_uint128_t *	result
	)

Subtracts the uint128_t b from the uint128_t a.

This function assumes that the result is >= 0. result == a or result == b is not allowed. a == b is allowed.

Parameters

[in]	a	A pointer to a sc_uint128_t.
[in]	b	A pointer to a sc_uint128_t.
[out]	result	A pointer to a sc_uint128_t. The difference a - b will be saved in result.

◆ sc_uint128_sub_inplace()

void sc_uint128_sub_inplace	(	sc_uint128_t *	a,
		const sc_uint128_t *	b
	)

Subtracts the uint128_t b from the uint128_t a.

The result is saved in a. a == b is allowed. This function assumes that the result is >= 0.

Parameters

[in,out]	a	A pointer to a sc_uint128_t. a will be overwritten by a - b.
[in]	b	A pointer to a sc_uint128_t.

Data Structures

Typedefs

Functions

Detailed Description

Function Documentation

◆ sc_uint128_add()

◆ sc_uint128_add_inplace()

◆ sc_uint128_bitwise_and()

◆ sc_uint128_bitwise_and_inplace()

◆ sc_uint128_bitwise_neg()

◆ sc_uint128_bitwise_or()

◆ sc_uint128_bitwise_or_inplace()

◆ sc_uint128_chk_bit()

◆ sc_uint128_compare()

◆ sc_uint128_copy()

◆ sc_uint128_init()

◆ sc_uint128_is_equal()

◆ sc_uint128_set_bit()

◆ sc_uint128_shift_left()

◆ sc_uint128_shift_right()

◆ sc_uint128_sub()

◆ sc_uint128_sub_inplace()