Implement q15MulrSatSI16x8 for interpreter (#3984)

2 files changed, 11 insertions, 1 deletions

diff --git a/src/literal.h b/src/literal.h
index 965ec157c..0b1b6fa90 100644
--- a/src/literal.h
+++ b/src/literal.h
@@ -644,6 +644,7 @@ private:
   Literal subSatUI8(const Literal& other) const;
   Literal subSatSI16(const Literal& other) const;
   Literal subSatUI16(const Literal& other) const;
+  Literal q15MulrSatSI16(const Literal& other) const;
   Literal minInt(const Literal& other) const;
   Literal maxInt(const Literal& other) const;
   Literal minUInt(const Literal& other) const;
diff --git a/src/wasm/literal.cpp b/src/wasm/literal.cpp
index c3a2ddf7a..afaafe5e4 100644
--- a/src/wasm/literal.cpp
+++ b/src/wasm/literal.cpp
@@ -1070,6 +1070,14 @@ Literal Literal::subSatUI16(const Literal& other) const {
   return Literal(sub_sat_u<uint16_t>(geti32(), other.geti32()));
 }
 
+Literal Literal::q15MulrSatSI16(const Literal& other) const {
+  int64_t value =
+    (int64_t(geti32()) * int64_t(other.geti32()) + 0x4000LL) >> 15LL;
+  int64_t lower = std::numeric_limits<int16_t>::min();
+  int64_t upper = std::numeric_limits<int16_t>::max();
+  return Literal(int16_t(std::min(std::max(value, lower), upper)));
+}
+
 Literal Literal::mul(const Literal& other) const {
   switch (type.getBasic()) {
     case Type::i32:
@@ -2201,7 +2209,8 @@ Literal Literal::avgrUI16x8(const Literal& other) const {
   return binary<8, &Literal::getLanesUI16x8, &Literal::avgrUInt>(*this, other);
 }
 Literal Literal::q15MulrSatSI16x8(const Literal& other) const {
-  WASM_UNREACHABLE("TODO: implement Q15 rounding, saturating multiplication");
+  return binary<8, &Literal::getLanesSI16x8, &Literal::q15MulrSatSI16>(*this,
+                                                                       other);
 }
 Literal Literal::addI32x4(const Literal& other) const {
   return binary<4, &Literal::getLanesI32x4, &Literal::add>(*this, other);