diff --git a/cl/_testdata/print/out.ll b/cl/_testdata/print/out.ll
index 2e91fdad..691e954e 100644
--- a/cl/_testdata/print/out.ll
+++ b/cl/_testdata/print/out.ll
@@ -322,7 +322,7 @@ _llgo_15:                                         ; preds = %_llgo_13
   br i1 %40, label %_llgo_16, label %_llgo_17
 
 _llgo_16:                                         ; preds = %_llgo_15
-  %41 = sext i8 %39 to i64
+  %41 = zext i8 %39 to i64
   call void @main.printuint(i64 %41)
   br label %_llgo_1
 
@@ -335,7 +335,7 @@ _llgo_17:                                         ; preds = %_llgo_15
   br i1 %46, label %_llgo_18, label %_llgo_19
 
 _llgo_18:                                         ; preds = %_llgo_17
-  %47 = sext i16 %45 to i64
+  %47 = zext i16 %45 to i64
   call void @main.printuint(i64 %47)
   br label %_llgo_1
 
@@ -348,7 +348,7 @@ _llgo_19:                                         ; preds = %_llgo_17
   br i1 %52, label %_llgo_20, label %_llgo_21
 
 _llgo_20:                                         ; preds = %_llgo_19
-  %53 = sext i32 %51 to i64
+  %53 = zext i32 %51 to i64
   call void @main.printuint(i64 %53)
   br label %_llgo_1
 
diff --git a/cl/_testrt/builtin/in.go b/cl/_testrt/builtin/in.go
index 00857a49..cb936a02 100644
--- a/cl/_testrt/builtin/in.go
+++ b/cl/_testrt/builtin/in.go
@@ -25,5 +25,5 @@ func main() {
 	data = append(data, "def"...)
 	println(data)
 	var i any = 100
-	println(true, 100, -100, uint(100), int32(-100), 100.5, i, &i, uintptr(unsafe.Pointer(&i)))
+	println(true, 100, -100, uint(255), int32(-100), 100.5, i, &i, uintptr(unsafe.Pointer(&i)))
 }
diff --git a/cl/_testrt/builtin/out.ll b/cl/_testrt/builtin/out.ll
index 5cd53638..70a9fb85 100644
--- a/cl/_testrt/builtin/out.ll
+++ b/cl/_testrt/builtin/out.ll
@@ -292,7 +292,7 @@ _llgo_0:
   call void @"github.com/goplus/llgo/internal/runtime.PrintInt"(i64 -100)
   %129 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @37, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %129)
-  call void @"github.com/goplus/llgo/internal/runtime.PrintUint"(i64 100)
+  call void @"github.com/goplus/llgo/internal/runtime.PrintUint"(i64 255)
   %130 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @38, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %130)
   call void @"github.com/goplus/llgo/internal/runtime.PrintInt"(i64 -100)
diff --git a/cl/_testrt/cast/out.ll b/cl/_testrt/cast/out.ll
index 65c7100b..5e6f5e05 100644
--- a/cl/_testrt/cast/out.ll
+++ b/cl/_testrt/cast/out.ll
@@ -199,7 +199,7 @@ _llgo_2:                                          ; preds = %_llgo_0
 
 define void @main.cvtUinptr(i32 %0, i64 %1) {
 _llgo_0:
-  %2 = sext i32 %0 to i64
+  %2 = zext i32 %0 to i64
   %3 = icmp ne i64 %2, %1
   br i1 %3, label %_llgo_1, label %_llgo_2
 
diff --git a/cl/_testrt/mask/out.ll b/cl/_testrt/mask/out.ll
index c64b738f..99f341da 100644
--- a/cl/_testrt/mask/out.ll
+++ b/cl/_testrt/mask/out.ll
@@ -57,7 +57,7 @@ _llgo_0:
   %9 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @2, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %9)
   %10 = call i8 @main.mask_shl8u(i8 127, i64 5)
-  %11 = sext i8 %10 to i64
+  %11 = zext i8 %10 to i64
   call void @"github.com/goplus/llgo/internal/runtime.PrintUint"(i64 %11)
   %12 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @3, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %12)
@@ -67,7 +67,7 @@ _llgo_0:
   %15 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @4, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %15)
   %16 = call i8 @main.mask_shl8u(i8 127, i64 16)
-  %17 = sext i8 %16 to i64
+  %17 = zext i8 %16 to i64
   call void @"github.com/goplus/llgo/internal/runtime.PrintUint"(i64 %17)
   %18 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @5, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %18)
@@ -81,7 +81,7 @@ _llgo_0:
   %23 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @7, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %23)
   %24 = call i8 @main.mask_shr8u(i8 127, i64 5)
-  %25 = sext i8 %24 to i64
+  %25 = zext i8 %24 to i64
   call void @"github.com/goplus/llgo/internal/runtime.PrintUint"(i64 %25)
   %26 = call %"github.com/goplus/llgo/internal/runtime.String" @"github.com/goplus/llgo/internal/runtime.NewString"(ptr @8, i64 1)
   call void @"github.com/goplus/llgo/internal/runtime.PrintString"(%"github.com/goplus/llgo/internal/runtime.String" %26)
diff --git a/internal/abi/llgo_autogen.lla b/internal/abi/llgo_autogen.lla
index f2eafdd0..be9b522a 100644
Binary files a/internal/abi/llgo_autogen.lla and b/internal/abi/llgo_autogen.lla differ
diff --git a/internal/runtime/llgo_autogen.lla b/internal/runtime/llgo_autogen.lla
index 652fbb7f..ebb1ce75 100644
Binary files a/internal/runtime/llgo_autogen.lla and b/internal/runtime/llgo_autogen.lla differ
diff --git a/ssa/expr.go b/ssa/expr.go
index 1ebf1973..b1a050ac 100644
--- a/ssa/expr.go
+++ b/ssa/expr.go
@@ -1059,7 +1059,7 @@ func (b Builder) Convert(t Type, x Expr) (ret Expr) {
 	case *types.Basic:
 		switch typ.Kind() {
 		case types.Uintptr:
-			ret.impl = castInt(b.impl, x.impl, t.ll)
+			ret.impl = castUintptr(b, x.impl, t)
 			return
 		case types.UnsafePointer:
 			ret.impl = castPtr(b.impl, x.impl, t.ll)
@@ -1067,19 +1067,10 @@ func (b Builder) Convert(t Type, x Expr) (ret Expr) {
 		}
 		switch xtyp := x.RawType().Underlying().(type) {
 		case *types.Basic:
-			size := b.Prog.SizeOf(t)
-			xsize := b.Prog.SizeOf(x.Type)
 			if typ.Info()&types.IsInteger != 0 {
 				// int <- int/float
 				if xtyp.Info()&types.IsInteger != 0 {
-					// if xsize > size {
-					// 	ret.impl = b.impl.CreateTrunc(x.impl, t.ll, "")
-					// } else if typ.Info()&types.IsUnsigned != 0 {
-					// 	ret.impl = b.impl.CreateZExt(x.impl, t.ll, "")
-					// } else {
-					// 	ret.impl = b.impl.CreateSExt(x.impl, t.ll, "")
-					// }
-					ret.impl = castInt(b.impl, x.impl, t.ll)
+					ret.impl = castInt(b, x.impl, t)
 					return
 				} else if xtyp.Info()&types.IsFloat != 0 {
 					if typ.Info()&types.IsUnsigned != 0 {
@@ -1099,11 +1090,7 @@ func (b Builder) Convert(t Type, x Expr) (ret Expr) {
 					}
 					return
 				} else if xtyp.Info()&types.IsFloat != 0 {
-					if xsize > size {
-						ret.impl = b.impl.CreateFPTrunc(x.impl, t.ll, "")
-					} else {
-						ret.impl = b.impl.CreateFPExt(x.impl, t.ll, "")
-					}
+					ret.impl = castFloat(b, x.impl, t)
 					return
 				}
 			}
@@ -1115,15 +1102,33 @@ func (b Builder) Convert(t Type, x Expr) (ret Expr) {
 	panic("todo")
 }
 
-func castInt(b llvm.Builder, x llvm.Value, t llvm.Type) llvm.Value {
-	xt := x.Type()
-	if xt.TypeKind() == llvm.PointerTypeKind {
-		return llvm.CreatePtrToInt(b, x, t)
+func castUintptr(b Builder, x llvm.Value, typ Type) llvm.Value {
+	if x.Type().TypeKind() == llvm.PointerTypeKind {
+		return llvm.CreatePtrToInt(b.impl, x, typ.ll)
 	}
-	if xt.IntTypeWidth() <= t.IntTypeWidth() {
-		return llvm.CreateIntCast(b, x, t)
+	return castInt(b, x, typ)
+}
+
+func castInt(b Builder, x llvm.Value, typ Type) llvm.Value {
+	xsize := b.Prog.td.TypeAllocSize(x.Type())
+	size := b.Prog.td.TypeAllocSize(typ.ll)
+	if xsize > size {
+		return b.impl.CreateTrunc(x, typ.ll, "")
+	} else if typ.kind == vkUnsigned {
+		return b.impl.CreateZExt(x, typ.ll, "")
+	} else {
+		return b.impl.CreateSExt(x, typ.ll, "")
+	}
+}
+
+func castFloat(b Builder, x llvm.Value, typ Type) llvm.Value {
+	xsize := b.Prog.td.TypeAllocSize(x.Type())
+	size := b.Prog.td.TypeAllocSize(typ.ll)
+	if xsize > size {
+		return b.impl.CreateFPTrunc(x, typ.ll, "")
+	} else {
+		return b.impl.CreateFPExt(x, typ.ll, "")
 	}
-	return llvm.CreateTrunc(b, x, t)
 }
 
 func castPtr(b llvm.Builder, x llvm.Value, t llvm.Type) llvm.Value {
@@ -1245,12 +1250,12 @@ func (b Builder) TypeAssert(x Expr, assertedTyp Type, commaOk bool) (ret Expr) {
 			conv := func(v llvm.Value) llvm.Value {
 				switch kind {
 				case types.Float32:
-					v = castInt(b.impl, v, b.Prog.tyInt32())
+					v = castInt(b, v, b.Prog.Type(types.Typ[types.Int32], InC))
 					v = b.impl.CreateBitCast(v, assertedTyp.ll, "")
 				case types.Float64:
 					v = b.impl.CreateBitCast(v, assertedTyp.ll, "")
 				default:
-					v = castInt(b.impl, v, assertedTyp.ll)
+					v = castInt(b, v, assertedTyp)
 				}
 				return v
 			}