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[crypto] Expose shifted out bit from big integer shifts

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Expose the bit shifted out as a result of shifting a big integer left
or right.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2025-02-13 14:18:15 +00:00
parent bd90abf487
commit 5056e8ad93
7 changed files with 146 additions and 85 deletions
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36
src/arch/riscv/include/bits/bigint.h
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@@ -143,38 +143,40 @@ bigint_subtract_raw ( const unsigned long *subtrahend0, unsigned long *value0,
*
* @v value0 Element 0 of big integer
* @v size Number of elements
* @ret out Bit shifted out
*/
static inline __attribute__ (( always_inline )) void
static inline __attribute__ (( always_inline )) int
bigint_shl_raw ( unsigned long *value0, unsigned int size ) {
bigint_t ( size ) __attribute__ (( may_alias )) *value =
( ( void * ) value0 );
unsigned long *valueN = ( value0 + size );
unsigned long *discard_value;
unsigned long discard_value_i;
unsigned long discard_carry;
unsigned long discard_temp;
unsigned long carry;
__asm__ __volatile__ ( "\n1:\n\t"
/* Load value[i] */
LOADN " %1, (%0)\n\t"
/* Shift left */
"slli %3, %1, 1\n\t"
"or %3, %3, %2\n\t"
"srli %2, %1, %7\n\t"
"slli %2, %1, 1\n\t"
"or %2, %2, %3\n\t"
"srli %3, %1, %7\n\t"
/* Store value[i] */
STOREN " %3, (%0)\n\t"
STOREN " %2, (%0)\n\t"
/* Loop */
"addi %0, %0, %6\n\t"
"bne %0, %5, 1b\n\t"
: "=&r" ( discard_value ),
"=&r" ( discard_value_i ),
"=&r" ( discard_carry ),
"=&r" ( discard_temp ),
"=&r" ( carry ),
"+m" ( *value )
: "r" ( valueN ),
"i" ( sizeof ( unsigned long ) ),
"i" ( ( 8 * sizeof ( unsigned long ) - 1 ) ),
"0" ( value0 ), "2" ( 0 ) );
"0" ( value0 ), "3" ( 0 ) );
return carry;
}
/**
@@ -182,38 +184,40 @@ bigint_shl_raw ( unsigned long *value0, unsigned int size ) {
*
* @v value0 Element 0 of big integer
* @v size Number of elements
* @ret out Bit shifted out
*/
static inline __attribute__ (( always_inline )) void
static inline __attribute__ (( always_inline )) int
bigint_shr_raw ( unsigned long *value0, unsigned int size ) {
bigint_t ( size ) __attribute__ (( may_alias )) *value =
( ( void * ) value0 );
unsigned long *valueN = ( value0 + size );
unsigned long *discard_value;
unsigned long discard_value_i;
unsigned long discard_carry;
unsigned long discard_temp;
unsigned long carry;
__asm__ __volatile__ ( "\n1:\n\t"
/* Load value[i] */
LOADN " %1, %6(%0)\n\t"
/* Shift right */
"srli %3, %1, 1\n\t"
"or %3, %3, %2\n\t"
"slli %2, %1, %7\n\t"
"srli %2, %1, 1\n\t"
"or %2, %2, %3\n\t"
"slli %3, %1, %7\n\t"
/* Store value[i] */
STOREN " %3, %6(%0)\n\t"
STOREN " %2, %6(%0)\n\t"
/* Loop */
"addi %0, %0, %6\n\t"
"bne %0, %5, 1b\n\t"
: "=&r" ( discard_value ),
"=&r" ( discard_value_i ),
"=&r" ( discard_carry ),
"=&r" ( discard_temp ),
"=&r" ( carry ),
"+m" ( *value )
: "r" ( value0 ),
"i" ( -( sizeof ( unsigned long ) ) ),
"i" ( ( 8 * sizeof ( unsigned long ) - 1 ) ),
"0" ( valueN ), "2" ( 0 ) );
"0" ( valueN ), "3" ( 0 ) );
return ( !! carry );
}
/**