Added ISWAP instruction

Scratchpad -> 2 MiB
New scratchpad initialization
New dataset initialization

src/squareHash.h

@@ -0,0 +1,71 @@
+/*
+Copyright (c) 2019 tevador
+
+This file is part of RandomX.
+
+RandomX is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+RandomX is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with RandomX.  If not, see<http://www.gnu.org/licenses/>.
+*/
+
+#include <stdint.h>
+
+#if !defined(_M_X64) && !defined(__x86_64__)
+
+typedef struct {
+	uint64_t lo;
+	uint64_t hi;
+} uint128_t;
+
+#define LO(x) ((x)&0xffffffff)
+#define HI(x) ((x)>>32)
+static inline uint128_t square128(uint64_t x) {
+	uint64_t xh = HI(x), xl = LO(x);
+	uint64_t xll = xl * xl;
+	uint64_t xlh = xl * xh;
+	uint64_t xhh = xh * xh;
+	uint64_t m1 = 2 * LO(xlh) + HI(xll);
+	uint64_t m2 = 2 * HI(xlh) + LO(xhh) + HI(m1);
+	uint64_t m3 = HI(xhh) + HI(m2);
+
+	uint128_t x2;
+
+	x2.lo = (m1 << 32) + LO(xll);
+	x2.hi = (m3 << 32) + LO(m2);
+
+	return x2;
+}
+#undef LO(x)
+#undef HI(x)
+
+inline uint64_t squareHash(uint64_t x) {
+	x += 1613783669344650115;
+	for (int i = 0; i < 42; ++i) {
+		uint128_t x2 = square128(x);
+		x = x2.lo - x2.hi;
+	}
+	return x;
+}
+
+#else
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+uint64_t squareHash(uint64_t);
+
+#if defined(__cplusplus)
+}
+#endif
+
+#endif