From 92fdd07ca38525507f405f4f2c0068225675258c Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Tue, 7 Dec 2021 08:24:04 -0600
Subject: [PATCH] Address #889 - Switch high and low bits of part of number
 hash (Knuth's multiplicative hash)

Also make sure we weren't throwing away 3 bits of entropy.
---
 src/core/value.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/core/value.c b/src/core/value.c
index 38fae844..e1a82f32 100644
--- a/src/core/value.c
+++ b/src/core/value.c
@@ -324,7 +324,8 @@ int32_t janet_hash(Janet x) {
             as.d = janet_unwrap_number(x);
             uint32_t lo = (uint32_t)(as.u & 0xFFFFFFFF);
             uint32_t hi = (uint32_t)(as.u >> 32);
-            hash = (int32_t)((hi ^ (lo >> 3)) * 2654435769u);
+            uint32_t hilo = (hi ^ lo) * 2654435769u;
+            hash = (int32_t)((hilo << 16) | ((hilo >> 16) & 0xFFFF));
             break;
         }
         case JANET_ABSTRACT: {