s390x: [liftoff] implement FP copysign

Change-Id: I60683dd37939d330169e3879982a6ac9ca7694a2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2718230Reviewed-by: Milad Fa <mfarazma@redhat.com>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/master@{#73033}

src/wasm/baseline/s390/liftoff-assembler-s390.h

@@ -1146,6 +1146,40 @@ void LiftoffAssembler::emit_u32_to_intptr(Register dst, Register src) {
 #endif
 }
 
+void LiftoffAssembler::emit_f32_copysign(DoubleRegister dst, DoubleRegister lhs,
+                                         DoubleRegister rhs) {
+  constexpr uint64_t kF64SignBit = uint64_t{1} << 63;
+  UseScratchRegisterScope temps(this);
+  Register scratch2 = temps.Acquire();
+  MovDoubleToInt64(r0, lhs);
+  // Clear sign bit in {r0}.
+  AndP(r0, Operand(~kF64SignBit));
+
+  MovDoubleToInt64(scratch2, rhs);
+  // Isolate sign bit in {scratch2}.
+  AndP(scratch2, Operand(kF64SignBit));
+  // Combine {scratch2} into {r0}.
+  OrP(r0, r0, scratch2);
+  MovInt64ToDouble(dst, r0);
+}
+
+void LiftoffAssembler::emit_f64_copysign(DoubleRegister dst, DoubleRegister lhs,
+                                         DoubleRegister rhs) {
+  constexpr uint64_t kF64SignBit = uint64_t{1} << 63;
+  UseScratchRegisterScope temps(this);
+  Register scratch2 = temps.Acquire();
+  MovDoubleToInt64(r0, lhs);
+  // Clear sign bit in {r0}.
+  AndP(r0, Operand(~kF64SignBit));
+
+  MovDoubleToInt64(scratch2, rhs);
+  // Isolate sign bit in {scratch2}.
+  AndP(scratch2, Operand(kF64SignBit));
+  // Combine {scratch2} into {r0}.
+  OrP(r0, r0, scratch2);
+  MovInt64ToDouble(dst, r0);
+}
+
 bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
                                             LiftoffRegister dst,
                                             LiftoffRegister src, Label* trap) {
@@ -2517,16 +2551,6 @@ void LiftoffStackSlots::Construct() {
   asm_->bailout(kUnsupportedArchitecture, "LiftoffStackSlots::Construct");
 }
 
-void LiftoffAssembler::emit_f64_copysign(DoubleRegister dst, DoubleRegister lhs,
-                                         DoubleRegister rhs) {
-  bailout(kUnsupportedArchitecture, "emit_f64_copysign");
-}
-
-void LiftoffAssembler::emit_f32_copysign(DoubleRegister dst, DoubleRegister lhs,
-                                         DoubleRegister rhs) {
-  bailout(kUnsupportedArchitecture, "emit_f32_copysign");
-}
-
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8