#ifndef _BITS_BIGINT_H
#define _BITS_BIGINT_H
/** @file
*
* Big integer support
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <string.h>
#include <strings.h>
/** Element of a big integer */
typedef uint64_t bigint_element_t;
/**
* Initialise big integer
*
* @v value0 Element 0 of big integer to initialise
* @v size Number of elements
* @v data Raw data
* @v len Length of raw data
*/
static inline __attribute__ (( always_inline )) void
bigint_init_raw ( uint64_t *value0, unsigned int size,
const void *data, size_t len ) {
size_t pad_len = ( sizeof ( bigint_t ( size ) ) - len );
uint8_t *value_byte = ( ( void * ) value0 );
const uint8_t *data_byte = ( data + len );
/* Copy raw data in reverse order, padding with zeros */
while ( len-- )
*(value_byte++) = *(--data_byte);
while ( pad_len-- )
*(value_byte++) = 0;
}
/**
* Add big integers
*
* @v addend0 Element 0 of big integer to add
* @v value0 Element 0 of big integer to be added to
* @v size Number of elements
*/
static inline __attribute__ (( always_inline )) void
bigint_add_raw ( const uint64_t *addend0, uint64_t *value0,
unsigned int size ) {
bigint_t ( size ) __attribute__ (( may_alias )) *value =
( ( void * ) value0 );
uint64_t *discard_addend;
uint64_t *discard_value;
uint64_t discard_addend_i;
uint64_t discard_value_i;
unsigned int discard_size;
__asm__ __volatile__ ( "cmn xzr, xzr\n\t" /* clear CF */
"\n1:\n\t"
"ldr %3, [%0], #8\n\t"
"ldr %4, [%1]\n\t"
"adcs %4, %4, %3\n\t"
"str %4, [%1], #8\n\t"
"sub %w2, %w2, #1\n\t"
"cbnz %w2, 1b\n\t"
: "=r" ( discard_addend ),
"=r" ( discard_value ),
"=r" ( discard_size ),
"=r" ( discard_addend_i ),
"=r" ( discard_value_i ),
"+m" ( *value )
: "0" ( addend0 ), "1" ( value0 ), "2" ( size )
: "cc" );
}
/**
* Subtract big integers
*
* @v subtrahend0 Element 0 of big integer to subtract
* @v value0 Element 0 of big integer to be subtracted from
* @v size Number of elements
*/
static inline __attribute__ (( always_inline )) void
bigint_subtract_raw ( const uint64_t *subtrahend0, uint64_t *value0,
unsigned int size ) {
bigint_t ( size ) __attribute__ (( may_alias )) *value =
( ( void * ) value0 );
uint64_t *discard_subtrahend;
uint64_t *discard_value;
uint64_t discard_subtrahend_i;
uint64_t discard_value_i;
unsigned int discard_size;
__asm__ __volatile__ ( "cmp xzr, xzr\n\t" /* set CF */
"\n1:\n\t"
"ldr %3, [%0], #8\n\t"
"ldr %4, [%1]\n\t"
"sbcs %4, %4, %3\n\t"
"str %4, [%1], #8\n\t"
"sub %w2, %w2, #1\n\t"
"cbnz %w2, 1b\n\t"
: "=r" ( discard_subtrahend ),
"=r" ( discard_value ),
"=r" ( discard_size ),
"=r" ( discard_subtrahend_i ),
"=r" ( discard_value_i ),
"+m" ( *value )
: "0" ( subtrahend0 ), "1" ( value0 ),
"2" ( size )
: "cc" );
}
/**
* Rotate big integer left
*
* @v value0 Element 0 of big integer
* @v size Number of elements
*/
static inline __attribute__ (( always_inline )) void
bigint_rol_raw ( uint64_t *value0, unsigned int size ) {
bigint_t ( size ) __attribute__ (( may_alias )) *value =
( ( void * ) value0 );
uint64_t *discard_value;
uint64_t discard_value_i;
unsigned int discard_size;
__asm__ __volatile__ ( "cmn xzr, xzr\n\t" /* clear CF */
"\n1:\n\t"
"ldr %2, [%0]\n\t"
"adcs %2, %2, %2\n\t"
"str %2, [%0], #8\n\t"
"sub %w1, %w1, #1\n\t"
"cbnz %w1, 1b\n\t"
: "=r" ( discard_value ),
"=r" ( discard_size ),
"=r" ( discard_value_i ),
"+m" ( *value )
: "0" ( value0 ), "1" ( size )
: "cc" );
}
/**
* Rotate big integer right
*
* @v value0 Element 0 of big integer
* @v size Number of elements
*/
static inline __attribute__ (( always_inline )) void
bigint_ror_raw ( uint64_t *value0, unsigned int size ) {
bigint_t ( size ) __attribute__ (( may_alias )) *value =
( ( void * ) value0 );
uint64_t *discard_value;
uint64_t discard_value_i;
uint64_t discard_value_j;
unsigned int discard_size;
__asm__ __volatile__ ( "mov %3, #0\n\t"
"\n1:\n\t"
"sub %w1, %w1, #1\n\t"
"ldr %2, [%0, %1, lsl #3]\n\t"
"extr %3, %3, %2, #1\n\t"
"str %3, [%0, %1, lsl #3]\n\t"
"mov %3, %2\n\t"
"cbnz %w1, 1b\n\t"
: "=r" ( discard_value ),
"=r" ( discard_size ),
"=r" ( discard_value_i ),
"=r" ( discard_value_j ),
"+m" ( *value )
: "0" ( value0 ), "1" ( size ) );
}
/**
* Test if big integer is equal to zero
*
* @v value0 Element 0 of big integer
* @v size Number of elements
* @ret is_zero Big integer is equal to zero
*/
static inline __attribute__ (( always_inline, pure )) int
bigint_is_zero_raw ( const uint64_t *value0, unsigned int size ) {
const uint64_t *value = value0;
uint64_t value_i;
do {
value_i = *(value++);
if ( value_i )
break;
} while ( --size );
return ( value_i == 0 );
}
/**
* Compare big integers
*
* @v value0 Element 0 of big integer
* @v reference0 Element 0 of reference big integer
* @v size Number of elements
* @ret geq Big integer is greater than or equal to the reference
*/
static inline __attribute__ (( always_inline, pure )) int
bigint_is_geq_raw ( const uint64_t *value0, const uint64_t *reference0,
unsigned int size ) {
const uint64_t *value = ( value0 + size );
const uint64_t *reference = ( reference0 + size );
uint64_t value_i;
uint64_t reference_i;
do {
value_i = *(--value);
reference_i = *(--reference);
if ( value_i != reference_i )
break;
} while ( --size );
return ( value_i >= reference_i );
}
/**
* Test if bit is set in big integer
*
* @v value0 Element 0 of big integer
* @v size Number of elements
* @v bit Bit to test
* @ret is_set Bit is set
*/
static inline __attribute__ (( always_inline )) int
bigint_bit_is_set_raw ( const uint64_t *value0, unsigned int size,
unsigned int bit ) {
const bigint_t ( size ) __attribute__ (( may_alias )) *value =
( ( const void * ) value0 );
unsigned int index = ( bit / ( 8 * sizeof ( value->element[0] ) ) );
unsigned int subindex = ( bit % ( 8 * sizeof ( value->element[0] ) ) );
return ( !! ( value->element[index] & ( 1UL << subindex ) ) );
}
/**
* Find highest bit set in big integer
*
* @v value0 Element 0 of big integer
* @v size Number of elements
* @ret max_bit Highest bit set + 1 (or 0 if no bits set)
*/
static inline __attribute__ (( always_inline )) int
bigint_max_set_bit_raw ( const uint64_t *value0, unsigned int size ) {
const uint64_t *value = ( value0 + size );
int max_bit = ( 8 * sizeof ( bigint_t ( size ) ) );
uint64_t value_i;
do {
value_i = *(--value);
max_bit -= ( 64 - fls ( value_i ) );
if ( value_i )
break;
} while ( --size );
return max_bit;
}
/**
* Grow big integer
*
* @v source0 Element 0 of source big integer
* @v source_size Number of elements in source big integer
* @v dest0 Element 0 of destination big integer
* @v dest_size Number of elements in destination big integer
*/
static inline __attribute__ (( always_inline )) void
bigint_grow_raw ( const uint64_t *source0, unsigned int source_size,
uint64_t *dest0, unsigned int dest_size ) {
unsigned int pad_size = ( dest_size - source_size );
memcpy ( dest0, source0, sizeof ( bigint_t ( source_size ) ) );
memset ( ( dest0 + source_size ), 0, sizeof ( bigint_t ( pad_size ) ) );
}
/**
* Shrink big integer
*
* @v source0 Element 0 of source big integer
* @v source_size Number of elements in source big integer
* @v dest0 Element 0 of destination big integer
* @v dest_size Number of elements in destination big integer
*/
static inline __attribute__ (( always_inline )) void
bigint_shrink_raw ( const uint64_t *source0, unsigned int source_size __unused,
uint64_t *dest0, unsigned int dest_size ) {
memcpy ( dest0, source0, sizeof ( bigint_t ( dest_size ) ) );
}
/**
* Finalise big integer
*
* @v value0 Element 0 of big integer to finalise
* @v size Number of elements
* @v out Output buffer
* @v len Length of output buffer
*/
static inline __attribute__ (( always_inline )) void
bigint_done_raw ( const uint64_t *value0, unsigned int size __unused,
void *out, size_t len ) {
const uint8_t *value_byte = ( ( const void * ) value0 );
uint8_t *out_byte = ( out + len );
/* Copy raw data in reverse order */
while ( len-- )
*(--out_byte) = *(value_byte++);
}
extern void bigint_multiply_raw ( const uint64_t *multiplicand0,
unsigned int multiplicand_size,
const uint64_t *multiplier0,
unsigned int multiplier_size,
uint64_t *value0 );
#endif /* _BITS_BIGINT_H */
