From 4bedff2ff3d2763ce5c18b23bab0f6f635ff3312 Mon Sep 17 00:00:00 2001
From: Alex Beregszaszi <alex@rtfs.hu>
Date: Wed, 26 Oct 2016 22:44:42 +0100
Subject: [PATCH] Implement EIP150.1b (all but 64th rule)

---
 lib/opFns.js | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/opFns.js b/lib/opFns.js
index a678388182..b60d46ccd7 100644
--- a/lib/opFns.js
+++ b/lib/opFns.js
@@ -549,6 +549,8 @@ module.exports = {
 
     checkCallMemCost(runState, options, localOpts)
 
+    gasLimit = calcCallLimit(runState, gasLimit)
+
     stateManager.exists(toAddress, function (err, exists) {
       if (err) {
         done(err)
@@ -883,3 +885,14 @@ function makeCall (runState, callOptions, localOpts, cb) {
     }
   }
 }
+
+function calcCallLimit (runState, gas) {
+  if (!runState.enableHomesteadReprice) {
+    return gas
+  }
+
+  // div should round down
+  const max = runState.gasLimit.sub(runState.gasLimit.div(64))
+
+  return BN.min(gas, max)
+}