From 6dd32647b554bcee757edf6dc9c31ce18fd9f6af Mon Sep 17 00:00:00 2001
From: Adam Wick <awick@uhsure.com>
Date: Fri, 7 Feb 2020 16:03:49 -0600
Subject: [PATCH] Fix signed addition and subtraction.

---
 generation/src/Conversions.hs            | 78 +++++++++++++++---------
 generation/src/Subtract.hs               |  8 +--
 generation/src/generation.code-workspace | 11 ++++
 3 files changed, 65 insertions(+), 32 deletions(-)
 create mode 100644 generation/src/generation.code-workspace

diff --git a/generation/src/Conversions.hs b/generation/src/Conversions.hs
index ecf32ed..c038d73 100644
--- a/generation/src/Conversions.hs
+++ b/generation/src/Conversions.hs
@@ -567,8 +567,58 @@ generateSignedCryptonumConversions source otherSizes = concatMap convert otherSi
          tuName = mkIdent ("U" ++ show target)
          sEntries = toLit (source `div` 64)
          tEntries = toLit (target `div` 64)
+         sTop     = toLit ((source `div` 64) - 1)
+         extensions = map (\ x ->
+                            let xLit = toLit x
+                            in [stmt| res.contents.value[$$(xLit)] = extension; |])
+                          [(source `div` 64)..((target `div` 64) - 1)]
      in case compare source target of
           LT -> [
+            [item|
+             impl<'a> From<&'a $$sName> for $$tsName {
+               fn from(x: &$$sName) -> $$tsName {
+                 let mut res = $$tsName::zero();
+                 res.contents.value[0..$$(sEntries)].copy_from_slice(&x.contents.value);
+                 let extension = if x.contents.value[$$(sTop)] & 0x8000_0000_0000_0000 == 0 {
+                    0
+                 } else {
+                    0xFFFF_FFFF_FFFF_FFFFu64
+                 };
+                 $@{extensions}
+                 res
+               }
+             }
+            |],
+            [item|
+             impl From<$$sName> for $$tsName {
+               fn from(x: $$sName) -> $$tsName {
+                 $$tsName::from(&x)
+               }
+             }
+            |],
+            [item|
+             impl<'a> TryFrom<&'a $$sName> for $$tuName {
+               type Error = ConversionError;
+
+
+               fn try_from(x: &$$sName) -> Result<$$tuName,ConversionError> {
+                 if x.is_negative() {
+                   Err(ConversionError::NegativeToUnsigned)
+                 } else {
+                   Ok($$tuName::from(&x.contents))
+                 }
+               }
+             }
+            |],
+            [item|
+             impl TryFrom<$$sName> for $$tuName {
+               type Error = ConversionError;
+
+               fn try_from(x: $$sName) -> Result<$$tuName,ConversionError> {
+                 $$tuName::try_from(&x)
+               }
+             }
+            |]
            ]
           EQ -> [
             [item|
@@ -618,33 +668,5 @@ generateSignedCryptonumConversions source otherSizes = concatMap convert otherSi
             |]
            ]
           GT -> [
-            [item|
-              impl From<$$tuName> for $$sName {
-                fn from(x: $$tuName) -> $$sName {
-                  $$sName::from(&x)
-                }
-              }
-            |],
-            [item|
-              impl<'a> From<&'a $$tuName> for $$sName {
-                fn from(x: &$$tuName) -> $$sName {
-                  panic!("from1")
-                }
-              }
-            |],
-            [item|
-              impl From<$$tsName> for $$sName {
-                fn from(x: $$tsName) -> $$sName {
-                  $$sName::from(&x)
-                }
-              }
-            |],
-            [item|
-              impl<'a> From<&'a $$tsName> for $$sName {
-                fn from(x: &$$tsName) -> $$sName {
-                  panic!("from2")
-                }
-              }
-            |]   
            ]
 
diff --git a/generation/src/Subtract.hs b/generation/src/Subtract.hs
index 58d96d7..8d99609 100644
--- a/generation/src/Subtract.hs
+++ b/generation/src/Subtract.hs
@@ -35,7 +35,7 @@ safeSignedSubtractOps :: File
 safeSignedSubtractOps = File {
     predicate = \ me others -> (me + 64) `elem` others,
     outputName = "safe_ssub",
-    isUnsigned = True,
+    isUnsigned = False,
     generator = declareSafeSignedSubtractOperators,
     testCase = Just generateSafeSignedTests
 }
@@ -53,7 +53,7 @@ unsafeSignedSubtractOps :: File
 unsafeSignedSubtractOps = File {
     predicate = \ _ _ -> True,
     outputName = "unsafe_ssub",
-    isUnsigned = True,
+    isUnsigned = False,
     generator = declareUnsafeSignedSubtractOperators,
     testCase = Just generateUnsafeSignedTests
 }
@@ -166,7 +166,7 @@ declareSafeSignedSubtractOperators bitsize _ =
           type Output = $$dname;
 
           fn sub(self, rhs: &$$sname) -> $$dname {
-            panic!("sub")
+            $$dname{ contents: &self.contents - &rhs.contents }
           }
         }
 
@@ -254,7 +254,7 @@ declareUnsafeSignedSubtractOperators bitsize _ =
 
         impl<'a> SubAssign<&'a $$sname> for $$sname {
           fn sub_assign(&mut self, rhs: &Self) {
-            panic!("sub_assign")
+            self.contents -= &rhs.contents;
           }
         }
 
diff --git a/generation/src/generation.code-workspace b/generation/src/generation.code-workspace
new file mode 100644
index 0000000..a9563b9
--- /dev/null
+++ b/generation/src/generation.code-workspace
@@ -0,0 +1,11 @@
+{
+	"folders": [
+		{
+			"path": "/Users/awick/projects/cryptonum/generation"
+		},
+		{
+			"path": "/Users/awick/projects/cryptonum/src"
+		}
+	],
+	"settings": {}
+}
\ No newline at end of file