From 070a06bf62eeb201d551dfe822a2bfb446bd37c7 Mon Sep 17 00:00:00 2001
From: Kris Kwiatkowski <contact@amongbytes.com>
Date: Wed, 10 Mar 2021 15:55:06 +0000
Subject: [PATCH] WIP

---
 CMakeLists.txt                                | 10 +++++
 .../dilithium/dilithium2/clean/rounding.c     | 40 +++++++++++++++++--
 2 files changed, 47 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 59387f7b..b66b286f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,8 @@ set(CMAKE_VERBOSE_MAKEFILE ON)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "~/.cmake/Modules")
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "3rd/cmake-modules")
 set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_INTERPROCEDURAL_OPTIMIZATION ON)
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 
 string(TOLOWER "${CMAKE_BUILD_TYPE}" CMAKE_BUILD_TYPE_LOWER)
 
@@ -301,6 +303,14 @@ define_kem_alg(
   lightsaber_clean
   PQCLEAN_LIGHTSABER_CLEAN "${SRC_CLEAN_LIGHTSABER}" "${INC_CLEAN_LIGHTSABER}")
 
+#function(define_frodo_src path)
+#endif()
+# -rw-r--r-- 1 kris kris 13783 Mar  1 12:35 kem.c
+# -rw-r--r-- 1 kris kris  3343 Mar  1 12:35 matrix_shake.c
+# -rw-r--r-- 1 kris kris  1426 Mar  1 12:35 noise.c
+# -rw-r--r-- 1 kris kris  9202 Mar  1 12:35 util.c
+
+
 # AVX2 targets
 if(${ARCH} STREQUAL "ARCH_x86_64")
 
diff --git a/src/sign/dilithium/dilithium2/clean/rounding.c b/src/sign/dilithium/dilithium2/clean/rounding.c
index 9b49fb2f..23310cb1 100644
--- a/src/sign/dilithium/dilithium2/clean/rounding.c
+++ b/src/sign/dilithium/dilithium2/clean/rounding.c
@@ -1,6 +1,8 @@
 #include "params.h"
 #include "rounding.h"
 #include <stdint.h>
+#include <stdio.h>
+#include <assert.h>
 
 /*************************************************
 * Name:        PQCLEAN_DILITHIUM2_CLEAN_power2round
@@ -37,14 +39,46 @@ int32_t PQCLEAN_DILITHIUM2_CLEAN_power2round(int32_t *a0, int32_t a)  {
 * Returns a1.
 **************************************************/
 int32_t PQCLEAN_DILITHIUM2_CLEAN_decompose(int32_t *a0, int32_t a) {
-    int32_t a1;
+    int32_t a1 = 0;
+    uint64_t r;
 
+    int32_t r0, r1;
+
+    assert(a>0); assert(a<Q);
+
+    // mod ALPHA
+    static const uint32_t u = 360800;
+    r = ((uint64_t)a)*u;
+    r >>= 36;
+    r *= 2 * GAMMA2;
+    r = a - r;
+
+    if (r>(2*GAMMA2)) {
+        r -= 2*GAMMA2;
+    }
+
+    r1 = ((int32_t)r)*2*GAMMA2;
+
+    // centrize
+    if (r > GAMMA2) {
+        *a0 = (int32_t)r - 2*GAMMA2;
+    } else {
+        *a0 = r;
+    }
+
+    // CASE: r-r0 = q-1 => r1=0, r0 = r0-1
+
+    // OLD
     a1  = (a + 127) >> 7;
     a1  = (a1 * 11275 + (1 << 23)) >> 24;
     a1 ^= ((43 - a1) >> 31) & a1;
 
-    *a0  = a - a1 * 2 * GAMMA2;
-    *a0 -= (((Q - 1) / 2 - *a0) >> 31) & Q;
+    // TODO: ten sam trick co w barrett
+    int32_t a2 = ((uint64_t)a-*a0)/(2*GAMMA2);
+
+    //*a0  = a - a1 * 2 * GAMMA2;
+    //*a0 -= (((Q - 1) / 2 - *a0) >> 31) & Q;
+    printf("(%d, %d,\n)", a1, a2);
     return a1;
 }