add test for precise float32 support, allow 3 modes of precise float32 support, and rename option to PRECISE_F32 to be consistent with other precision options

1 files changed, 7 insertions, 1 deletions

diff --git a/src/settings.js b/src/settings.js
index 3ea513cb..de9ab46c 100644
--- a/src/settings.js
+++ b/src/settings.js
@@ -115,7 +115,13 @@ var PRECISE_I64_MATH = 1; // If enabled, i64 addition etc. is emulated - which i
 var PRECISE_I32_MUL = 1; // If enabled, i32 multiplication is done with full precision, which means it is
                          // correct even if the value exceeds the JS double-integer limit of ~52 bits (otherwise,
                          // rounding will occur above that range).
-var FROUND = 0; // Use Math.fround (polyfilling when necessary)
+var PRECISE_F32 = 0; // 0: Use JS numbers for floating-point values. These are 64-bit and do not model C++
+                     //    floats exactly, which are 32-bit.
+                     // 1: Model C++ floats precisely, using Math.fround, polyfilling when necessary. This
+                     //    can be slow if the polyfill is used on heavy float32 computation.
+                     // 2: Model C++ floats precisely using Math.fround if available in the JS engine, otherwise
+                     //    use an empty polyfill. This will have less of a speed penalty than using the full
+                     //    polyfill in cases where engine support is not present.
 
 var CLOSURE_ANNOTATIONS = 0; // If set, the generated code will be annotated for the closure
                              // compiler. This potentially lets closure optimize the code better.