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src/arch/riscv/include/bits/bigint.h
315 строк
9 KB
Michael Brown
[crypto] Use inline assembly for bigint_grow() and bigint_shrink()
16 июн 2026, 18:07
16 июн 2026, 18:07
cd873a2
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#ifndef _BITS_BIGINT_H #define _BITS_BIGINT_H /** @file * * Big integer support */ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); FILE_SECBOOT ( PERMITTED ); /** Element of a big integer */ typedef unsigned long bigint_element_t; /** * 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 * @ret carry Carry out */ static inline __attribute__ (( always_inline )) int bigint_add_raw ( const unsigned long *addend0, unsigned long *value0, unsigned int size ) { bigint_t ( size ) __attribute__ (( may_alias )) *value = ( ( void * ) value0 ); unsigned long *valueN = ( value0 + size ); unsigned long *discard_addend; unsigned long *discard_value; unsigned long discard_addend_i; unsigned long discard_value_i; unsigned long discard_temp; unsigned long carry; __asm__ __volatile__ ( "\n1:\n\t" /* Load addend[i] and value[i] */ LOADN " %2, (%0)\n\t" LOADN " %3, (%1)\n\t" /* Add carry flag and addend */ "add %3, %3, %5\n\t" "sltu %4, %3, %5\n\t" "add %3, %3, %2\n\t" "sltu %5, %3, %2\n\t" "or %5, %4, %5\n\t" /* Store value[i] */ STOREN " %3, (%1)\n\t" /* Loop */ "addi %0, %0, %8\n\t" "addi %1, %1, %8\n\t" "bne %1, %7, 1b\n\t" : "=&r" ( discard_addend ), "=&r" ( discard_value ), "=&r" ( discard_addend_i ), "=&r" ( discard_value_i ), "=&r" ( discard_temp ), "=&r" ( carry ), "+m" ( *value ) : "r" ( valueN ), "i" ( sizeof ( unsigned long ) ), "0" ( addend0 ), "1" ( value0 ), "5" ( 0 ) ); return carry; } /** * 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 * @ret borrow Borrow out */ static inline __attribute__ (( always_inline )) int bigint_subtract_raw ( const unsigned long *subtrahend0, unsigned long *value0, unsigned int size ) { bigint_t ( size ) __attribute__ (( may_alias )) *value = ( ( void * ) value0 ); unsigned long *valueN = ( value0 + size ); unsigned long *discard_subtrahend; unsigned long *discard_value; unsigned long discard_subtrahend_i; unsigned long discard_value_i; unsigned long discard_temp; unsigned long borrow; __asm__ __volatile__ ( "\n1:\n\t" /* Load subtrahend[i] and value[i] */ LOADN " %2, (%0)\n\t" LOADN " %3, (%1)\n\t" /* Subtract carry flag and subtrahend */ "sltu %4, %3, %5\n\t" "sub %3, %3, %5\n\t" "sltu %5, %3, %2\n\t" "sub %3, %3, %2\n\t" "or %5, %5, %4\n\t" /* Store value[i] */ STOREN " %3, (%1)\n\t" /* Loop */ "addi %0, %0, %8\n\t" "addi %1, %1, %8\n\t" "bne %1, %7, 1b\n\t" : "=&r" ( discard_subtrahend ), "=&r" ( discard_value ), "=&r" ( discard_subtrahend_i ), "=&r" ( discard_value_i ), "=&r" ( discard_temp ), "=&r" ( borrow ), "+m" ( *value ) : "r" ( valueN ), "i" ( sizeof ( unsigned long ) ), "0" ( subtrahend0 ), "1" ( value0 ), "5" ( 0 ) ); return borrow; } /** * Shift big integer left * * @v value0 Element 0 of big integer * @v size Number of elements * @ret out Bit shifted out */ 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_temp; unsigned long carry; __asm__ __volatile__ ( "\n1:\n\t" /* Load value[i] */ LOADN " %1, (%0)\n\t" /* Shift left */ "slli %2, %1, 1\n\t" "or %2, %2, %3\n\t" "srli %3, %1, %7\n\t" /* Store value[i] */ 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_temp ), "=&r" ( carry ), "+m" ( *value ) : "r" ( valueN ), "i" ( sizeof ( unsigned long ) ), "i" ( ( 8 * sizeof ( unsigned long ) - 1 ) ), "0" ( value0 ), "3" ( 0 ) ); return carry; } /** * Shift big integer right * * @v value0 Element 0 of big integer * @v size Number of elements * @ret out Bit shifted out */ 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_temp; unsigned long carry; __asm__ __volatile__ ( "\n1:\n\t" /* Load value[i] */ LOADN " %1, %6(%0)\n\t" /* Shift right */ "srli %2, %1, 1\n\t" "or %2, %2, %3\n\t" "slli %3, %1, %7\n\t" /* Store value[i] */ 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_temp ), "=&r" ( carry ), "+m" ( *value ) : "r" ( value0 ), "i" ( -( sizeof ( unsigned long ) ) ), "i" ( ( 8 * sizeof ( unsigned long ) - 1 ) ), "0" ( valueN ), "3" ( 0 ) ); return ( !! carry ); } /** * 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 unsigned long *source0, unsigned int source_size, unsigned long *dest0, unsigned int dest_size ) { bigint_t ( dest_size ) __attribute__ (( may_alias )) *dest = ( ( void * ) dest0 ); const unsigned long *sourceN = ( source0 + source_size ); unsigned long *destN = ( dest0 + dest_size ); unsigned long *discard_source; unsigned long *discard_dest; unsigned long discard_source_i; __asm__ __volatile__ ( "\n1:\n\t" /* Copy dest[i] */ LOADN " %2, (%0)\n\t" STOREN " %2, (%1)\n\t" /* Loop */ "addi %0, %0, %6\n\t" "addi %1, %1, %6\n\t" "bne %0, %4, 1b\n\t" "j 3f\n\t" "\n2:\n\t" /* Zero dest[i] */ STOREN " zero, (%1)\n\t" /* Loop */ "addi %1, %1, %6\n\t" "\n3:\n\t" "bne %1, %5, 2b\n\t" : "=&r" ( discard_source ), "=&r" ( discard_dest ), "=&r" ( discard_source_i ), "=m" ( *dest ) : "r" ( sourceN ), "r" ( destN ), "i" ( sizeof ( unsigned long ) ), "0" ( source0 ), "1" ( dest0 ) ); } /** * 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 unsigned long *source0, unsigned int source_size __unused, unsigned long *dest0, unsigned int dest_size ) { bigint_t ( dest_size ) __attribute__ (( may_alias )) *dest = ( ( void * ) dest0 ); unsigned long *destN = ( dest0 + dest_size ); unsigned long *discard_source; unsigned long *discard_dest; unsigned long discard_source_i; __asm__ __volatile__ ( "\n1:\n\t" /* Copy dest[i] */ LOADN " %2, (%0)\n\t" STOREN " %2, (%1)\n\t" /* Loop */ "addi %0, %0, %5\n\t" "addi %1, %1, %5\n\t" "bne %1, %4, 1b\n\t" : "=&r" ( discard_source ), "=&r" ( discard_dest ), "=&r" ( discard_source_i ), "=m" ( *dest ) : "r" ( destN ), "i" ( sizeof ( unsigned long ) ), "0" ( source0 ), "1" ( dest0 ) ); } /** * Multiply big integer elements * * @v multiplicand Multiplicand element * @v multiplier Multiplier element * @v result Result element * @v carry Carry element */ static inline __attribute__ (( always_inline )) void bigint_multiply_one ( const unsigned long multiplicand, const unsigned long multiplier, unsigned long *result, unsigned long *carry ) { unsigned long discard_low; unsigned long discard_high; unsigned long discard_carry; __asm__ __volatile__ ( /* Perform multiplication */ "mulhu %1, %5, %6\n\t" "mul %0, %5, %6\n\t" /* Accumulate low half */ "add %3, %3, %0\n\t" "sltu %2, %3, %0\n\t" "add %1, %1, %2\n\t" /* Accumulate carry (cannot overflow) */ "add %3, %3, %4\n\t" "sltu %2, %3, %4\n\t" "add %4, %1, %2\n\t" : "=r" ( discard_low ), "=&r" ( discard_high ), "=r" ( discard_carry ), "+r" ( *result ), "+r" ( *carry ) : "r" ( multiplicand ), "r" ( multiplier ) ); } #endif /* _BITS_BIGINT_H */