From 4ce59c023b3e2989c7ee530bc699b7ecea28e162 Mon Sep 17 00:00:00 2001
From: sowle <crypto.sowle@gmail.com>
Date: Sat, 24 Apr 2021 04:45:30 +0300
Subject: [PATCH] crypto: fe_cmp implemented

---
 src/crypto/crypto-ops.c | 10 ++++++++++
 src/crypto/crypto-ops.h |  1 +
 2 files changed, 11 insertions(+)

diff --git a/src/crypto/crypto-ops.c b/src/crypto/crypto-ops.c
index 1623c0d5..2ab08dc2 100644
--- a/src/crypto/crypto-ops.c
+++ b/src/crypto/crypto-ops.c
@@ -342,6 +342,16 @@ int fe_isnonzero(const fe f) {
     s[27] | s[28] | s[29] | s[30] | s[31]) - 1) >> 8) + 1;
 }
 
+int fe_cmp(const fe a, const fe b)
+{
+  for (size_t i = 9; i != SIZE_MAX; --i)
+  {
+    if ((const uint32_t)a[i] < (const uint32_t)b[i]) return -1;
+    if ((const uint32_t)a[i] > (const uint32_t)b[i]) return 1;
+  }
+  return 0;
+}
+
 /* From fe_mul.c */
 
 /*
diff --git a/src/crypto/crypto-ops.h b/src/crypto/crypto-ops.h
index b1dc2f88..6fb6917c 100644
--- a/src/crypto/crypto-ops.h
+++ b/src/crypto/crypto-ops.h
@@ -138,6 +138,7 @@ void sc_invert(unsigned char*, const unsigned char*);
 
 void fe_sq(fe h, const fe f);
 int fe_isnonzero(const fe f);
+int fe_cmp(const fe a, const fe b);
 void fe_mul(fe, const fe, const fe);
 void fe_frombytes(fe h, const unsigned char *s);
 void fe_invert(fe out, const fe z);