From b43c5dba0ec18fe5a5204537855ea2b73fc674c6 Mon Sep 17 00:00:00 2001
From: J08nY
Date: Mon, 23 Dec 2019 02:05:35 +0100
Subject: Implement multipliers.

---
 pyecsca/codegen/templates/mult_diff_ldr.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
 create mode 100644 pyecsca/codegen/templates/mult_diff_ldr.c

(limited to 'pyecsca/codegen/templates/mult_diff_ldr.c')

diff --git a/pyecsca/codegen/templates/mult_diff_ldr.c b/pyecsca/codegen/templates/mult_diff_ldr.c
new file mode 100644
index 0000000..2683116
--- /dev/null
+++ b/pyecsca/codegen/templates/mult_diff_ldr.c
@@ -0,0 +1,29 @@
+#include "mult.h"
+#include "point.h"
+
+void scalar_mult(bn_t *scalar, point_t *point, curve_t *curve, point_t *out) {
+	point_t *p0 = point_copy(&curve->neutral);
+	point_t *p1 = point_copy(point);
+	{%- if scalarmult.complete %}
+		int nbits = bn_bit_length(&curve->n) - 1;
+	{%- else %}
+		int nbits = bn_bit_length(scalar) - 1;
+	{%- endif %}
+
+	for (int i = nbits; i >= 0; i--) {
+		if (bn_get_bit(scalar, i) == 0) {
+			point_dadd(point, p0, p1, curve, p1);
+			point_dbl(p0, curve, p0);
+		} else {
+			point_dadd(point, p0, p1, curve, p0);
+			point_dbl(p1, curve, p1);
+		}
+	}
+
+	{%- if "scl" in scalarmult.formulas %}
+    	point_scl(p0, curve, p0);
+    {%- endif %}
+	point_set(p0, out);
+	point_free(p0);
+	point_free(p1);
+}
\ No newline at end of file
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