1 files changed, 61 insertions, 0 deletions
diff --git a/third_party/bearssl/src/i15_mulacc.c b/third_party/bearssl/src/i15_mulacc.c
new file mode 100644
index 0000000..7a073ac
--- /dev/null
+++ b/third_party/bearssl/src/i15_mulacc.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2017 Thomas Pornin <[email protected]>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining 
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be 
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "inner.h"
+
+/* see inner.h */
+void
+br_i15_mulacc(uint16_t *d, const uint16_t *a, const uint16_t *b)
+{
+	size_t alen, blen, u;
+	unsigned dl, dh;
+
+	alen = (a[0] + 15) >> 4;
+	blen = (b[0] + 15) >> 4;
+
+	/*
+	 * Announced bit length of d[] will be the sum of the announced
+	 * bit lengths of a[] and b[]; but the lengths are encoded.
+	 */
+	dl = (a[0] & 15) + (b[0] & 15);
+	dh = (a[0] >> 4) + (b[0] >> 4);
+	d[0] = (dh << 4) + dl + (~(uint32_t)(dl - 15) >> 31);
+
+	for (u = 0; u < blen; u ++) {
+		uint32_t f;
+		size_t v;
+		uint32_t cc;
+
+		f = b[1 + u];
+		cc = 0;
+		for (v = 0; v < alen; v ++) {
+			uint32_t z;
+
+			z = (uint32_t)d[1 + u + v] + MUL15(f, a[1 + v]) + cc;
+			cc = z >> 15;
+			d[1 + u + v] = z & 0x7FFF;
+		}
+		d[1 + u + alen] = cc;
+	}
+}