Initial project import

tools/v/vlib/math/bits/bits.arm64.v

@@ -0,0 +1,55 @@
+// Copyright (c) 2019-2024 Alexander Medvednikov. All rights reserved.
+// Use of this source code is governed by an MIT license
+// that can be found in the LICENSE file.
+module bits
+
+// mul_64 returns the 128-bit product of x and y: (hi, lo) = x * y
+// with the product bits' upper half returned in hi and the lower
+// half returned in lo.
+//
+// This function's execution time does not depend on the inputs.
+@[inline]
+pub fn mul_64(x u64, y u64) (u64, u64) {
+	mut hi := u64(0)
+	mut lo := u64(0)
+	$if arm64 && !tinyc {
+		asm arm64 {
+			mul lo, x, y
+			umulh hi, x, y
+			; =&r (hi)
+			  =&r (lo)
+			; r (x)
+			  r (y)
+			; cc
+		}
+		return hi, lo
+	}
+	// cross compile
+	return mul_64_default(x, y)
+}
+
+// mul_add_64 returns the 128-bit result of x * y + z: (hi, lo) = x * y + z
+// with the result bits' upper half returned in hi and the lower
+// half returned in lo.
+@[inline]
+pub fn mul_add_64(x u64, y u64, z u64) (u64, u64) {
+	mut hi := u64(0)
+	mut lo := u64(0)
+	$if arm64 && !tinyc {
+		asm arm64 {
+			mul lo, x, y
+			umulh hi, x, y
+			adds lo, lo, z
+			adc hi, hi, xzr
+			; =&r (hi)
+			  =&r (lo)
+			; r (x)
+			  r (y)
+			  r (z)
+			; cc
+		}
+		return hi, lo
+	}
+	// cross compile
+	return mul_add_64_default(x, y, z)
+}