fix bug

Author: lxq015

src/reflect/abi.go

@@ -479,6 +479,20 @@ func intFromReg(r *abi.RegArgs, reg int, argSize uintptr, to unsafe.Pointer) {
 // argSize must be non-zero, fit in a register, and a power-of-two.
 func intToReg(r *abi.RegArgs, reg int, argSize uintptr, from unsafe.Pointer) {
 	memmove(r.IntRegArgAddr(reg, argSize), from, argSize)
+
+	if argSize < goarch.PtrSize {
+		regBytes := unsafe.Slice((*byte)(unsafe.Pointer(&r.Ints[reg])), goarch.PtrSize)
+		if goarch.BigEndian {
+			offset := goarch.PtrSize - argSize
+			for i := uintptr(0); i < offset; i++ {
+				regBytes[i] = 0
+			}
+		} else {
+			for i := argSize; i < goarch.PtrSize; i++ {
+				regBytes[i] = 0
+			}
+		}
+	}
 }
 
 // floatFromReg loads a float value from its register representation in r.