note on CORRECT_OVERFLOWS

2 files changed, 5 insertions, 1 deletions

diff --git a/src/preamble.js b/src/preamble.js
index 847d2d95..eaa02c90 100644
--- a/src/preamble.js
+++ b/src/preamble.js
@@ -129,7 +129,8 @@ function cRound(x) {
 //========================================
 // Debugging tools - Mathop overflows
 //========================================
-function CHECK_OVERFLOW(value, bits) {
+function CHECK_OVERFLOW(value, bits, ignore) {
+  if (ignore) return value;
   if (value === Infinity || value === -Infinity || Math.abs(value) >= Math.pow(2, bits)) {
     CorrectionsMonitor.note('Overflow');
   }
diff --git a/src/settings.js b/src/settings.js
index 0243a191..249c8224 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -61,6 +61,9 @@ CHECK_OVERFLOWS = 0; // Add code that checks for overflows in integer math opera
                      // some factor, in order to get 'random' hash values - by taking
                      // that |value & hash_table_size| - then multiplying enough times will overflow.
                      // But instead, you can do |value = value & 30_BITS| in each iteration.
+                     // Note: CHECK_OVERFLOWS checks for overflows *after* CORRECT_OVERFLOWS
+                     // has operated (if it has). So you must run *without* CORRECT_OVERFLOWS
+                     // for this option to work. (Sorry for the discrepancy with CHECK_SIGNS - FIXME.)
 CORRECT_OVERFLOWS = 1; // Experimental code that tries to prevent unexpected JS overflows in integer
                        // mathops, by doing controlled overflows (sort of parallel to a CPU).
                        // Note that as mentioned above in CHECK_OVERFLOWS, the best thing is to