diff options
| author | Nicolai Stange <nicstange@gmail.com> | 2016-03-22 13:12:40 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2016-04-05 20:35:49 +0800 |
| commit | f00fa2417b3e1252b1a761f88731af03afff4407 (patch) | |
| tree | 1ba46a98908d23e0c95eb52b5e5a52173b7d06b9 | |
| parent | d755290689646fa66cc4830ca55569f2c9863666 (diff) | |
lib/mpi: mpi_read_buffer(): optimize skipping of leading zero limbs
Currently, if the number of leading zeros is greater than fits into a
complete limb, mpi_read_buffer() skips them by iterating over them
limb-wise.
Instead of skipping the high order zero limbs within the loop as shown
above, adjust the copying loop's bounds.
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
| -rw-r--r-- | lib/mpi/mpicoder.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c index 623439e4bad5..2fd8d418526c 100644 --- a/lib/mpi/mpicoder.c +++ b/lib/mpi/mpicoder.c @@ -184,7 +184,9 @@ int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes, p = buf; *nbytes = n - lzeros; - for (i = a->nlimbs - 1; i >= 0; i--) { + for (i = a->nlimbs - 1 - lzeros / BYTES_PER_MPI_LIMB, + lzeros %= BYTES_PER_MPI_LIMB; + i >= 0; i--) { alimb = a->d[i]; #if BYTES_PER_MPI_LIMB == 4 *p++ = alimb >> 24; @@ -205,15 +207,11 @@ int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes, #endif if (lzeros > 0) { - if (lzeros >= sizeof(alimb)) { - p -= sizeof(alimb); - } else { - mpi_limb_t *limb1 = (void *)p - sizeof(alimb); - mpi_limb_t *limb2 = (void *)p - sizeof(alimb) - + lzeros; - *limb1 = *limb2; - p -= lzeros; - } + mpi_limb_t *limb1 = (void *)p - sizeof(alimb); + mpi_limb_t *limb2 = (void *)p - sizeof(alimb) + + lzeros; + *limb1 = *limb2; + p -= lzeros; lzeros -= sizeof(alimb); } } |