Ported add_int64 and sub_int64 to jai.

1 files changed, 50 insertions, 0 deletions

diff --git a/unused.jai b/unused.jai
new file mode 100644
index 0000000..3529a46
--- /dev/null
+++ b/unused.jai
@@ -0,0 +1,50 @@
+checked_add :: (a: $T, b: T) -> result: T, overflow: bool 
+#modify {
+    if T.type == .INTEGER return;
+    T = null;
+}
+{
+    overflow: bool;
+    result: T = a + b;
+
+    info := type_info(T);
+    if info.signed {
+        // (+A) + (+B) = −C
+        // (−A) + (−B) = +C
+        if ((a > 0) && (b > 0) && (result < 0)) || ((a < 0) && (b < 0) && (result > 0)) {
+            overflow = true;
+        }
+    } else {
+        if result < a {
+            overflow = true;
+        }
+    }
+
+    return result, overflow;
+}
+
+checked_sub :: (a: $T, b: T) -> result: T, overflow: bool 
+#modify {
+    if T.type == .INTEGER return;
+    T = null;
+}
+{
+    overflow: bool;
+    result: T = a - b;
+
+    info := type_info(T);
+    if info.signed {
+        // (+A) − (−B) = −C
+        // (−A) − (+B) = +C
+        if ((a > 0) && (b < 0) && (result < 0)) || ((a < 0) && (b > 0) && (result > 0)) {
+            overflow = true;
+        }
+    } else {
+        if result > a {
+            overflow = true;
+        }
+    }
+
+    return result, overflow;
+}
+