Implemented the RoundInt64ToFloat32 TurboFan operator for x64, arm64, and mips64.

src/x64/assembler-x64.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 1064 matching lines @@
   void pslld(XMMRegister reg, byte imm8);
   void psrld(XMMRegister reg, byte imm8);
 
   void cvttsd2si(Register dst, const Operand& src);
   void cvttsd2si(Register dst, XMMRegister src);
   void cvttsd2siq(Register dst, XMMRegister src);
   void cvttsd2siq(Register dst, const Operand& src);
 
   void cvtlsi2sd(XMMRegister dst, const Operand& src);
   void cvtlsi2sd(XMMRegister dst, Register src);
+
+  void cvtqsi2ss(XMMRegister dst, const Operand& src);
+  void cvtqsi2ss(XMMRegister dst, Register src);
+
   void cvtqsi2sd(XMMRegister dst, const Operand& src);
   void cvtqsi2sd(XMMRegister dst, Register src);
 
 
   void cvtss2sd(XMMRegister dst, XMMRegister src);
   void cvtss2sd(XMMRegister dst, const Operand& src);
   void cvtsd2ss(XMMRegister dst, XMMRegister src);
   void cvtsd2ss(XMMRegister dst, const Operand& src);
 
   void cvtsd2si(Register dst, XMMRegister src);
@@ skipping 261 matching lines @@
   void vcvtss2sd(XMMRegister dst, XMMRegister src1, const Operand& src2) {
     vsd(0x5a, dst, src1, src2, kF3, k0F, kWIG);
   }
   void vcvtlsi2sd(XMMRegister dst, XMMRegister src1, Register src2) {
     XMMRegister isrc2 = {src2.code()};
     vsd(0x2a, dst, src1, isrc2, kF2, k0F, kW0);
   }
   void vcvtlsi2sd(XMMRegister dst, XMMRegister src1, const Operand& src2) {
     vsd(0x2a, dst, src1, src2, kF2, k0F, kW0);
   }
+  void vcvtqsi2ss(XMMRegister dst, XMMRegister src1, Register src2) {
+    XMMRegister isrc2 = {src2.code()};
+    vsd(0x2a, dst, src1, isrc2, kF3, k0F, kW1);
+  }
+  void vcvtqsi2ss(XMMRegister dst, XMMRegister src1, const Operand& src2) {
+    vsd(0x2a, dst, src1, src2, kF3, k0F, kW1);
+  }
   void vcvtqsi2sd(XMMRegister dst, XMMRegister src1, Register src2) {
     XMMRegister isrc2 = {src2.code()};
     vsd(0x2a, dst, src1, isrc2, kF2, k0F, kW1);
   }
   void vcvtqsi2sd(XMMRegister dst, XMMRegister src1, const Operand& src2) {
     vsd(0x2a, dst, src1, src2, kF2, k0F, kW1);
   }
   void vcvttsd2si(Register dst, XMMRegister src) {
     XMMRegister idst = {dst.code()};
     vsd(0x2c, idst, xmm0, src, kF2, k0F, kW0);
@@ skipping 786 matching lines @@
   Assembler* assembler_;
 #ifdef DEBUG
   int space_before_;
 #endif
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X64_ASSEMBLER_X64_H_