diff --git a/App/lib/core/Handles/HandlesExprCall.vp b/App/lib/core/Handles/HandlesExprCall.vp
index d23250c..f6b937e 100644
--- a/App/lib/core/Handles/HandlesExprCall.vp
+++ b/App/lib/core/Handles/HandlesExprCall.vp
@@ -5500,6 +5500,20 @@ def translate_call(pool: memhub.MemBuddy | t.CPtr,
                         if fpty is not None:
                             arg_val = HandlesExpr.coerce_to_type(
                                 builder, arg_val, fpty, arg)
+                    elif found_func.IsVarArg == 1:
+                        # Win64 变参 8 字节槽位：<64 位整数按 i64 传（sext 符号扩展），
+                        # f32 提升为 f64。若按原窄类型传，调用点只写 4 字节进 8 字节槽，
+                        # 高 4 字节残留旧栈数据，va_arg(i64) 读到垃圾（如 DefineTest
+                        # PAGE=%d 读到 0x400921FB00001000，高位是 PI 残留）。
+                        # 对齐 TPC FuncGen/Python-llvmlite 的 ABI 自动提升。
+                        ab_va: int = HandlesExpr.get_llvm_type_bits(arg_val.Ty)
+                        af_va: int = HandlesExpr.get_llvm_float_bits(arg_val.Ty)
+                        i64_va: llvmlite.LLVMType | t.CPtr = llvmlite.Int64(pool)
+                        if ab_va != 0 and ab_va < 64:
+                            arg_val = llvmlite.build_sext(builder, arg_val, i64_va)
+                        elif af_va == 32:
+                            arg_val = llvmlite.build_fpext(
+                                builder, arg_val, llvmlite.Double(pool))
                 arg_val.Next = None
                 if head is None:
                     head = arg_val