From 7c0e02ad488fa826cbfb69d0508aab0e427ce346 Mon Sep 17 00:00:00 2001
From: junderw <junderwood@bitcoinbank.co.jp>
Date: Wed, 12 Dec 2018 21:07:16 +0900
Subject: [PATCH] Fix Block to allow regtest target (easiest possible target)

---
 src/block.js             | 2 +-
 test/fixtures/block.json | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/block.js b/src/block.js
index 8c7f3a6..eb7f708 100644
--- a/src/block.js
+++ b/src/block.js
@@ -145,7 +145,7 @@ Block.calculateTarget = function (bits) {
   const exponent = ((bits & 0xff000000) >> 24) - 3
   const mantissa = bits & 0x007fffff
   const target = Buffer.alloc(32, 0)
-  target.writeUInt32BE(mantissa, 28 - exponent)
+  target.writeUIntBE(mantissa, 29 - exponent, 3)
   return target
 }
 
diff --git a/test/fixtures/block.json b/test/fixtures/block.json
index c7aa5f7..b4a1cfe 100644
--- a/test/fixtures/block.json
+++ b/test/fixtures/block.json
@@ -19,6 +19,10 @@
     {
       "bits": "cffca00",
       "expected": "00000000000000000000000000000000000000007fca00000000000000000000"
+    },
+    {
+      "bits": "207fffff",
+      "expected": "7fffff0000000000000000000000000000000000000000000000000000000000"
     }
   ],
   "valid": [