From 36d4b664adba3a927b1708d68f4754e90997b42f Mon Sep 17 00:00:00 2001
From: Simo Sorce <simo@redhat.com>
Date: Mon, 12 Nov 2018 13:59:06 -0500
Subject: [PATCH] Add mpn_get_base256
Converts limbs to uint8_t buffer without conditional jumps.
Signed-off-by: Simo Sorce <simo@redhat.com>
---
gmp-glue.c | 31 +++++++++++++++++++++++++++++++
gmp-glue.h | 5 +++++
2 files changed, 36 insertions(+)
diff --git a/gmp-glue.c b/gmp-glue.c
index c44332df..805b50c4 100644
--- a/gmp-glue.c
+++ b/gmp-glue.c
@@ -246,6 +246,37 @@ mpn_set_base256_le (mp_limb_t *rp, mp_size_t rn,
}
}
+void
+mpn_get_base256 (uint8_t *rp, size_t rn,
+ const mp_limb_t *xp, mp_size_t xn)
+{
+ unsigned bits;
+ mp_limb_t in;
+ for (bits = in = 0; xn > 0 && rn > 0; )
+ {
+ if (bits >= 8)
+ {
+ rp[--rn] = in;
+ in >>= 8;
+ bits -= 8;
+ }
+ else
+ {
+ uint8_t old = in;
+ in = *xp++;
+ xn--;
+ rp[--rn] = old | (in << bits);
+ in >>= (8 - bits);
+ bits += GMP_NUMB_BITS - 8;
+ }
+ }
+ while (rn > 0)
+ {
+ rp[--rn] = in;
+ in >>= 8;
+ }
+}
+
void
mpn_get_base256_le (uint8_t *rp, size_t rn,
const mp_limb_t *xp, mp_size_t xn)
diff --git a/gmp-glue.h b/gmp-glue.h
index 38cdd197..7f42cc2b 100644
--- a/gmp-glue.h
+++ b/gmp-glue.h
@@ -57,6 +57,7 @@
#define mpz_set_n _nettle_mpz_set_n
#define mpn_set_base256 _nettle_mpn_set_base256
#define mpn_set_base256_le _nettle_mpn_set_base256_le
+#define mpn_get_base256 _nettle_mpn_get_base256
#define mpn_get_base256_le _nettle_mpn_get_base256_le
#define gmp_alloc_limbs _nettle_gmp_alloc_limbs
#define gmp_free_limbs _nettle_gmp_free_limbs
@@ -150,6 +151,10 @@ void
mpn_set_base256_le (mp_limb_t *rp, mp_size_t rn,
const uint8_t *xp, size_t xn);
+void
+mpn_get_base256 (uint8_t *rp, size_t rn,
+ const mp_limb_t *xp, mp_size_t xn);
+
void
mpn_get_base256_le (uint8_t *rp, size_t rn,
const mp_limb_t *xp, mp_size_t xn);
--
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