From eb45d338eea0de6f1fb2ef15fbc23dbdc17022a6 Mon Sep 17 00:00:00 2001
From: bunnie <bunnie@kosagi.com>
Date: Fri, 21 Aug 2020 01:37:10 +0800
Subject: [PATCH] mods to get hardware integration to actually work.

---
 Cargo.toml        |  6 ++++--
 src/lib.rs        |  2 +-
 src/montgomery.rs | 11 +++++++++--
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index ea6dd72..6e822e8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -48,9 +48,11 @@ serde = { version = "1.0", default-features = false, optional = true, features =
 packed_simd = { version = "0.3", features = ["into_bits"], optional = true }
 zeroize = { version = "1", default-features = false }
 engine25519-as = { path="../engine25519-as", default-features = false, features = [] }
-rand = { version = "0.7" }
+rand = { version = "0.7", default-features = false, features = [] }
 volatile = "0.2.6"
-pac = { path = "../../../../sim_support/rust/pac" }
+#pac = { path = "../../../../sim_support/rust/pac" }  # used in test simulation environment, need to figure out how to make a switch for this
+betrusted-pac = { path = "../betrusted-pac" }
+#pac = { package = "betrusted-pac" }
 
 [features]
 nightly = ["subtle/nightly"]
diff --git a/src/lib.rs b/src/lib.rs
index 29e0a82..9930e48 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -65,7 +65,7 @@ pub(crate) mod macros;
 extern crate engine25519_as;
 extern crate rand;
 extern crate volatile;
-extern crate pac;
+extern crate betrusted_pac;
 
 //------------------------------------------------------------------------
 // curve25519-dalek public modules
diff --git a/src/montgomery.rs b/src/montgomery.rs
index cf65fa3..1e10ec4 100644
--- a/src/montgomery.rs
+++ b/src/montgomery.rs
@@ -296,7 +296,7 @@ pub fn differential_add_and_double_hw(
     affine_PmQ: &FieldElement,
 ) {
     use volatile::Volatile;
-    let p = unsafe { pac::Peripherals::steal() };
+    let p = unsafe { betrusted_pac::Peripherals::steal() };
     let mcode = assemble_engine25519!(
         start:
             // P.U in %20
@@ -443,9 +443,16 @@ impl<'a, 'b> Mul<&'b Scalar> for &'a MontgomeryPoint {
         copy_to_rf(x1.W.to_bytes(), 28);
         copy_to_rf(affine_u.to_bytes(), 24);
         copy_to_rf(scalar.bytes, 31);
+        // load the number 254 into the loop index register
+        copy_to_rf([
+            254, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+       ], 19);
 
         use volatile::Volatile;
-        let p = unsafe { pac::Peripherals::steal() };
+        let p = unsafe { betrusted_pac::Peripherals::steal() };
         let mcode = assemble_engine25519!(
             start:
                 // P.U in %20