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Centralize the definition of big number limb types

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This commit is contained in:
Rhys Weatherley
2015-03-31 09:43:09 +10:00
parent a3d7f61b96
commit 3bcfbcd43b
6 changed files with 79 additions and 48 deletions
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16
libraries/Crypto/examples/TestCurve25519Math/TestCurve25519Math.ino
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@@ -34,19 +34,17 @@ of the full curve operation itself.
#include <string.h>
// Copy some definitions from the Curve25519 class for convenience.
#define NUM_LIMBS (32 / sizeof(Curve25519::limb_t))
#define LIMB_BITS (8 * sizeof(Curve25519::limb_t))
#define limb_t Curve25519::limb_t
#define dlimb_t Curve25519::dlimb_t
#define NUM_LIMBS (32 / sizeof(limb_t))
#define LIMB_BITS (8 * sizeof(limb_t))
#define INVERSE_LIMB (~((limb_t)0))
// For simpleMod() below we need a type that is 4 times the size of limb_t.
#if CURVE25519_LIMB_8BIT
#if BIGNUMBER_LIMB_8BIT
#define qlimb_t uint32_t
#elif CURVE25519_LIMB_16BIT
#elif BIGNUMBER_LIMB_16BIT
#define qlimb_t uint64_t
#else
#define CURVE25519_NO_QLIMB 1
#define BIGNUMBER_NO_QLIMB 1
#endif
limb_t arg1[NUM_LIMBS];
@@ -222,7 +220,7 @@ void simpleMul(limb_t *result, const limb_t *x, const limb_t *y)
}
}
#if defined(CURVE25519_NO_QLIMB)
#if defined(BIGNUMBER_NO_QLIMB)
// Quick check to correct the estimate on a quotient word.
static inline limb_t correctEstimate
@@ -314,7 +312,7 @@ void simpleMod(limb_t *x)
// One subtlety of Knuth's algorithm is that it looks like the test
// is working with double-word quantities but it is actually using
// double-word plus a carry bit. So we need to use qlimb_t for this.
#if !defined(CURVE25519_NO_QLIMB)
#if !defined(BIGNUMBER_NO_QLIMB)
qlimb_t test = ((((qlimb_t)uword) - ((dlimb_t)q) * v[1]) << LIMB_BITS) + u[0];
if ((((dlimb_t)q) * v[0]) > test) {
--q;