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| author | Michael Brown <mcb30@ipxe.org> | 2025-02-13 14:18:15 +0000 |
|---|---|---|
| committer | Michael Brown <mcb30@ipxe.org> | 2025-02-13 15:25:35 +0000 |
| commit | 5056e8ad936742ba410031cff14c0f72d87805fc (patch) | |
| tree | 843fe48d0e4eeea4d78e4c30e31c16268def5ff3 /src/arch/x86/include/bits/bigint.h | |
| parent | bd90abf487a6b0500f457193f86ff54fd2be3143 (diff) | |
| download | ipxe-5056e8ad936742ba410031cff14c0f72d87805fc.tar.gz | |
[crypto] Expose shifted out bit from big integer shifts
Expose the bit shifted out as a result of shifting a big integer left
or right.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Diffstat (limited to 'src/arch/x86/include/bits/bigint.h')
| -rw-r--r-- | src/arch/x86/include/bits/bigint.h | 19 |
1 files changed, 13 insertions, 6 deletions
diff --git a/src/arch/x86/include/bits/bigint.h b/src/arch/x86/include/bits/bigint.h index 4026ca481..4bab3ebf7 100644 --- a/src/arch/x86/include/bits/bigint.h +++ b/src/arch/x86/include/bits/bigint.h @@ -116,22 +116,25 @@ bigint_subtract_raw ( const uint32_t *subtrahend0, uint32_t *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 ( uint32_t *value0, unsigned int size ) { bigint_t ( size ) __attribute__ (( may_alias )) *value = ( ( void * ) value0 ); long index; long discard_c; + int out; __asm__ __volatile__ ( "xor %0, %0\n\t" /* Zero %0 and clear CF */ "\n1:\n\t" - "rcll $1, (%3,%0,4)\n\t" + "rcll $1, (%4,%0,4)\n\t" "inc %0\n\t" /* Does not affect CF */ "loop 1b\n\t" : "=&r" ( index ), "=&c" ( discard_c ), - "+m" ( *value ) + "=@ccc" ( out ), "+m" ( *value ) : "r" ( value0 ), "1" ( size ) ); + return out; } /** @@ -139,19 +142,23 @@ bigint_shl_raw ( uint32_t *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 ( uint32_t *value0, unsigned int size ) { bigint_t ( size ) __attribute__ (( may_alias )) *value = ( ( void * ) value0 ); long discard_c; + int out; __asm__ __volatile__ ( "clc\n\t" "\n1:\n\t" - "rcrl $1, -4(%2,%0,4)\n\t" + "rcrl $1, -4(%3,%0,4)\n\t" "loop 1b\n\t" - : "=&c" ( discard_c ), "+m" ( *value ) + : "=&c" ( discard_c ), "=@ccc" ( out ), + "+m" ( *value ) : "r" ( value0 ), "0" ( size ) ); + return out; } /** |