Function SipRounds

freebsd/crypto/siphash/siphash.c:212–241

#define SIP_ROTL(x, b)	(uint64_t)(((x) << (b)) | ( (x) >> (64 - (b))))

static void
SipRounds(SIPHASH_CTX *ctx, int final)
{
	int rounds;

	if (!final)
		rounds = ctx->rounds_compr;
	else
		rounds = ctx->rounds_final;

	while (rounds--) {
		ctx->v[0] += ctx->v[1];
		ctx->v[2] += ctx->v[3];
		ctx->v[1] = SIP_ROTL(ctx->v[1], 13);
		ctx->v[3] = SIP_ROTL(ctx->v[3], 16);

		ctx->v[1] ^= ctx->v[0];
		ctx->v[3] ^= ctx->v[2];
		ctx->v[0] = SIP_ROTL(ctx->v[0], 32);

		ctx->v[2] += ctx->v[1];
		ctx->v[0] += ctx->v[3];
		ctx->v[1] = SIP_ROTL(ctx->v[1], 17);
		ctx->v[3] = SIP_ROTL(ctx->v[3], 21);

		ctx->v[1] ^= ctx->v[2];
		ctx->v[3] ^= ctx->v[0];
		ctx->v[2] = SIP_ROTL(ctx->v[2], 32);
	}
}