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authorNicolai Stange <nicstange@gmail.com>2016-03-22 13:12:40 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2016-04-05 20:35:49 +0800
commitf00fa2417b3e1252b1a761f88731af03afff4407 (patch)
tree1ba46a98908d23e0c95eb52b5e5a52173b7d06b9 /lib/mpi/mpicoder.c
parentd755290689646fa66cc4830ca55569f2c9863666 (diff)
downloadlinux-stericsson-f00fa2417b3e1252b1a761f88731af03afff4407.tar.gz
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>
Diffstat (limited to 'lib/mpi/mpicoder.c')
-rw-r--r--lib/mpi/mpicoder.c18
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);
}
}