Implement SHL and SHR

ethereumjs · Jan 30, 2018 · b0398e5 · b0398e5
1 parent d64f916
commit b0398e5
Showing 1 changed file with 23 additions and 0 deletions.
diff --git a/lib/opFns.js b/lib/opFns.js
@@ -162,6 +162,29 @@ module.exports = {
 
     return new BN(word[pos])
   },
+  SHL: function (a, b, runState) {
+    if (a.gten(256)) {
+      return new BN(0)
+    }
+    return b.shln(a.toNumber())
+  },
+  SHR: function (a, b, runState) {
+    if (a.gten(256)) {
+      return new BN(0)
+    }
+    return b.shrn(a.toNumber())
+  },
+  SAR: function (a, b, runState) {
+    b = b.fromTwos(256)
+    if (a.gten(256)) {
+      if (b.ltn(0)) {
+        return new BN(-1).toTwos(256)
+      } else {
+        return new BN(0)
+      }
+    }
+    // FIXME: implement
+  },
   // 0x20 range - crypto
   SHA3: function (offset, length, runState) {
     var data = memLoad(runState, offset, length)