From 0f5aec39e3b5906bdf63647fae185218e0c83011 Mon Sep 17 00:00:00 2001
From: Martin Taibr <taibr.martin@gmail.com>
Date: Tue, 15 Jan 2019 02:56:03 +0100
Subject: [PATCH] warn about bit ops

---
 qcsrc/lib/bits.qh | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/qcsrc/lib/bits.qh b/qcsrc/lib/bits.qh
index c158ea032..de11eef41 100644
--- a/qcsrc/lib/bits.qh
+++ b/qcsrc/lib/bits.qh
@@ -2,6 +2,9 @@
 
 #include "log.qh"
 
+/// Only ever assign into the first 24 bits in QC (so max is BIT(23)).
+/// QC converts the float to int, performs the bit operation, then converts it back.
+/// Assigning to the highest bits means some of the low ones might get lost due to float precision.
 #define BIT(n) (1 << (n))
 #define BITS(n) (BIT(n) - 1)
 #ifndef BRANCHLESS_BITSET
-- 
2.39.2