mirror of https://github.com/ipxe/ipxe.git
[loong64] Replace broken big integer arithmetic implementations
The slightly incomprehensible LoongArch64 implementation for bigint_subtract() is observed to produce incorrect results for some input values. Replace the suspicious LoongArch64 implementations of bigint_add(), bigint_subtract(), bigint_rol() and bigint_ror(), and add a test case for a subtraction that was producing an incorrect result with the previous implementation. Signed-off-by: Michael Brown <mcb30@ipxe.org>pull/1128/head
Michael Brown
parent
bac13ba1f6
commit
908174ec7e
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@ -53,34 +53,37 @@ bigint_add_raw ( const uint64_t *addend0, uint64_t *value0,
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uint64_t *discard_value;
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uint64_t discard_addend_i;
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uint64_t discard_value_i;
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uint64_t discard_carry;
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uint64_t discard_temp;
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unsigned int discard_size;
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__asm__ __volatile__ ( "move $t0, $zero\n"
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"1:\n\t"
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"ld.d %3, %0, 0\n\t"
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__asm__ __volatile__ ( "\n1:\n\t"
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/* Load addend[i] and value[i] */
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"ld.d %3, %0, 0\n\t"
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"ld.d %4, %1, 0\n\t"
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/* Add carry flag and addend */
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"add.d %4, %4, %5\n\t"
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"sltu %6, %4, %5\n\t"
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"add.d %4, %4, %3\n\t"
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"sltu %5, %4, %3\n\t"
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"or %5, %5, %6\n\t"
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/* Store value[i] */
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"st.d %4, %1, 0\n\t"
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/* Loop */
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"addi.d %0, %0, 8\n\t"
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"ld.d %4, %1, 0\n\t"
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"add.d %4, %4, $t0\n\t"
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"sltu $t0, %4, $t0\n\t"
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"add.d %4, %4, %3\n\t"
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"sltu $t1, %4, %3\n\t"
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"or $t0, $t0, $t1\n\t"
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"st.d %4, %1, 0\n\t"
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"addi.d %1, %1, 8\n\t"
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"addi.w %2, %2, -1\n\t"
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"bnez %2, 1b"
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"bnez %2, 1b\n\t"
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: "=r" ( discard_addend ),
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"=r" ( discard_value ),
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"=r" ( discard_size ),
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"=r" ( discard_addend_i ),
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"=r" ( discard_value_i ),
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"=r" ( discard_carry ),
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"=r" ( discard_temp ),
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"+m" ( *value )
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: "0" ( addend0 ),
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"1" ( value0 ),
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"2" ( size )
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: "t0", "t1" );
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: "0" ( addend0 ), "1" ( value0 ),
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"2" ( size ), "5" ( 0 ) );
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}
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/**
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@ -93,35 +96,43 @@ bigint_add_raw ( const uint64_t *addend0, uint64_t *value0,
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static inline __attribute__ (( always_inline )) void
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bigint_subtract_raw ( const uint64_t *subtrahend0, uint64_t *value0,
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unsigned int size ) {
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bigint_t ( size ) __attribute__ (( may_alias )) *value =
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( ( void * ) value0 );
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uint64_t *discard_subtrahend;
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uint64_t *discard_value;
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uint64_t discard_subtrahend_i;
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uint64_t discard_value_i;
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uint64_t discard_carry;
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uint64_t discard_temp;
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unsigned int discard_size;
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unsigned int flag = 0;
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discard_subtrahend = (uint64_t*) subtrahend0;
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discard_value = value0;
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discard_size = size;
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do {
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discard_subtrahend_i = *discard_subtrahend;
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discard_subtrahend++;
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discard_value_i = *discard_value;
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discard_value_i = discard_value_i - discard_subtrahend_i - flag;
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if ( *discard_value < (discard_subtrahend_i + flag)) {
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flag = 1;
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} else {
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flag = 0;
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}
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*discard_value = discard_value_i;
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discard_value++;
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discard_size -= 1;
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} while (discard_size != 0);
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__asm__ __volatile__ ( "\n1:\n\t"
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/* Load subtrahend[i] and value[i] */
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"ld.d %3, %0, 0\n\t"
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"ld.d %4, %1, 0\n\t"
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/* Subtract carry flag and subtrahend */
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"sltu %6, %4, %5\n\t"
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"sub.d %4, %4, %5\n\t"
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"sltu %5, %4, %3\n\t"
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"sub.d %4, %4, %3\n\t"
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"or %5, %5, %6\n\t"
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/* Store value[i] */
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"st.d %4, %1, 0\n\t"
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/* Loop */
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"addi.d %0, %0, 8\n\t"
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"addi.d %1, %1, 8\n\t"
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"addi.w %2, %2, -1\n\t"
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"bnez %2, 1b\n\t"
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: "=r" ( discard_subtrahend ),
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"=r" ( discard_value ),
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"=r" ( discard_size ),
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"=r" ( discard_subtrahend_i ),
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"=r" ( discard_value_i ),
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"=r" ( discard_carry ),
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"=r" ( discard_temp ),
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"+m" ( *value )
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: "0" ( subtrahend0 ), "1" ( value0 ),
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"2" ( size ), "5" ( 0 ) );
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}
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/**
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@ -132,30 +143,37 @@ bigint_subtract_raw ( const uint64_t *subtrahend0, uint64_t *value0,
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*/
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static inline __attribute__ (( always_inline )) void
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bigint_rol_raw ( uint64_t *value0, unsigned int size ) {
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bigint_t ( size ) __attribute__ (( may_alias )) *value =
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( ( void * ) value0 );
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uint64_t *discard_value;
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uint64_t discard_value_i;
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uint64_t discard_carry;
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uint64_t discard_temp;
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unsigned int discard_size;
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uint64_t current_value_i;
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unsigned int flag = 0;
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discard_value = value0;
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discard_size = size;
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do {
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discard_value_i = *discard_value;
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current_value_i = discard_value_i;
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discard_value_i += discard_value_i + flag;
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if (discard_value_i < current_value_i) {
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flag = 1;
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} else {
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flag = 0;
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}
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*discard_value = discard_value_i;
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discard_value++;
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discard_size -= 1;
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} while ( discard_size != 0 );
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__asm__ __volatile__ ( "\n1:\n\t"
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/* Load value[i] */
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"ld.d %2, %0, 0\n\t"
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/* Shift left */
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"rotri.d %2, %2, 63\n\t"
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"andi %4, %2, 1\n\t"
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"xor %2, %2, %4\n\t"
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"or %2, %2, %3\n\t"
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"move %3, %4\n\t"
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/* Store value[i] */
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"st.d %2, %0, 0\n\t"
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/* Loop */
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"addi.d %0, %0, 8\n\t"
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"addi.w %1, %1, -1\n\t"
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"bnez %1, 1b\n\t"
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: "=r" ( discard_value ),
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"=r" ( discard_size ),
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"=r" ( discard_value_i ),
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"=r" ( discard_carry ),
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"=r" ( discard_temp ),
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"+m" ( *value )
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: "0" ( value0 ), "1" ( size ), "3" ( 0 )
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: "cc" );
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}
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/**
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@ -166,27 +184,37 @@ bigint_rol_raw ( uint64_t *value0, unsigned int size ) {
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*/
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static inline __attribute__ (( always_inline )) void
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bigint_ror_raw ( uint64_t *value0, unsigned int size ) {
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bigint_t ( size ) __attribute__ (( may_alias )) *value =
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( ( void * ) value0 );
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uint64_t *discard_value;
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uint64_t discard_value_i;
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uint64_t discard_value_j;
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uint64_t discard_carry;
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uint64_t discard_temp;
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unsigned int discard_size;
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discard_value = value0;
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discard_size = size;
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discard_value_j = 0;
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do {
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discard_size -= 1;
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discard_value_i = *(discard_value + discard_size);
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discard_value_j = (discard_value_j << 63) | (discard_value_i >> 1);
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*(discard_value + discard_size) = discard_value_j;
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discard_value_j = discard_value_i;
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} while ( discard_size > 0 );
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__asm__ __volatile__ ( "\n1:\n\t"
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/* Load value[i] */
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"ld.d %2, %0, -8\n\t"
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/* Shift right */
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"andi %4, %2, 1\n\t"
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"xor %2, %2, %4\n\t"
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"or %2, %2, %3\n\t"
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"move %3, %4\n\t"
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"rotri.d %2, %2, 1\n\t"
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/* Store value[i] */
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"st.d %2, %0, -8\n\t"
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/* Loop */
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"addi.d %0, %0, -8\n\t"
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"addi.w %1, %1, -1\n\t"
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"bnez %1, 1b\n\t"
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: "=r" ( discard_value ),
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"=r" ( discard_size ),
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"=r" ( discard_value_i ),
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"=r" ( discard_carry ),
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"=r" ( discard_temp ),
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"+m" ( *value )
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: "0" ( value0 + size ), "1" ( size ), "3" ( 0 )
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: "cc" );
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}
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/**
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@ -714,6 +714,15 @@ static void bigint_test_exec ( void ) {
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bigint_subtract_ok ( BIGINT ( 0xbb, 0x77, 0x32, 0x5a ),
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BIGINT ( 0x5a, 0xd5, 0xfe, 0x28 ),
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BIGINT ( 0x9f, 0x5e, 0xcb, 0xce ) );
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bigint_subtract_ok ( BIGINT ( 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
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0xff, 0xff, 0xff, 0xff, 0xff, 0xff ),
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BIGINT ( 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x2a ),
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BIGINT ( 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x2b ) );
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bigint_subtract_ok ( BIGINT ( 0x7b, 0xaa, 0x16, 0xcf, 0x15, 0x87,
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0xe0, 0x4f, 0x2c, 0xa3, 0xec, 0x2f,
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0x46, 0xfb, 0x83, 0xc6, 0xe0, 0xee,
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