diff --git a/nac3artiq/src/lib.rs b/nac3artiq/src/lib.rs
index a01009bf0..22c28e480 100644
--- a/nac3artiq/src/lib.rs
+++ b/nac3artiq/src/lib.rs
@@ -163,6 +163,108 @@ impl Nac3 {
     }
 }
 
+// ARTIQ timeline control with now-pinning optimization.
+// This is a bit of mess due to endianness issues.
+// Modify gateware to make `now` little-endian, since we don't have OpenRISC anymore?
+fn timeline_builtins(primitive: &PrimitiveStore) -> Vec<(StrRef, FunSignature, Arc<GenCall>)> {
+    vec![(
+        "now_mu".into(),
+        FunSignature {
+            args: vec![],
+            ret: primitive.int64,
+            vars: HashMap::new(),
+        },
+        Arc::new(GenCall::new(Box::new(
+            |ctx, _, _, _| {
+                let i64_type = ctx.ctx.i64_type();
+                let now = ctx.module.get_global("now").unwrap_or_else(|| ctx.module.add_global(i64_type, None, "now"));
+                let now_raw = ctx.builder.build_load(now.as_pointer_value(), "now");
+                if let BasicValueEnum::IntValue(now_raw) = now_raw {
+                    let i64_32 = i64_type.const_int(32, false).into();
+                    let now_lo = ctx.builder.build_left_shift(now_raw, i64_32, "now_shl");
+                    let now_hi = ctx.builder.build_right_shift(now_raw, i64_32, false, "now_lshr").into();
+                    Some(ctx.builder.build_or(now_lo, now_hi, "now_or").into())
+                } else {
+                    unreachable!()
+                }
+            }
+        )))
+    ),(
+        "at_mu".into(),
+        FunSignature {
+            args: vec![FuncArg {
+                name: "t".into(),
+                ty: primitive.int64,
+                default_value: None,
+            }],
+            ret: primitive.none,
+            vars: HashMap::new(),
+        },
+        Arc::new(GenCall::new(Box::new(
+            |ctx, _, _, args| {
+                let i32_type = ctx.ctx.i64_type();
+                let i64_type = ctx.ctx.i64_type();
+                let i64_32 = i64_type.const_int(32, false).into();
+                if let BasicValueEnum::IntValue(time) = args[0].1 {
+                    let time_hi = ctx.builder.build_int_truncate(ctx.builder.build_right_shift(time, i64_32, false, "now_lshr"), i32_type, "now_trunc");
+                    let time_lo = ctx.builder.build_int_truncate(time, i32_type, "now_trunc");
+                    let now = ctx.module.get_global("now").unwrap_or_else(|| ctx.module.add_global(i64_type, None, "now"));
+                    let now_hiptr = ctx.builder.build_bitcast(now, i32_type.ptr_type(AddressSpace::Generic), "now_bitcast");
+                    if let BasicValueEnum::PointerValue(now_hiptr) = now_hiptr {
+                        let now_loptr = unsafe { ctx.builder.build_gep(now_hiptr, &[i32_type.const_int(1, false).into()], "now_gep") };
+                        ctx.builder.build_store(now_hiptr, time_hi);
+                        ctx.builder.build_store(now_loptr, time_lo);
+                        None
+                    } else {
+                        unreachable!();
+                    }
+                } else {
+                    unreachable!();
+                }
+            }
+        )))
+    ),(
+        "delay_mu".into(),
+        FunSignature {
+            args: vec![FuncArg {
+                name: "dt".into(),
+                ty: primitive.int64,
+                default_value: None,
+            }],
+            ret: primitive.none,
+            vars: HashMap::new(),
+        },
+        Arc::new(GenCall::new(Box::new(
+            |ctx, _, _, args| {
+                let i32_type = ctx.ctx.i64_type();
+                let i64_type = ctx.ctx.i64_type();
+                let i64_32 = i64_type.const_int(32, false).into();
+                let now = ctx.module.get_global("now").unwrap_or_else(|| ctx.module.add_global(i64_type, None, "now"));
+                let now_raw = ctx.builder.build_load(now.as_pointer_value(), "now");
+                if let (BasicValueEnum::IntValue(now_raw), BasicValueEnum::IntValue(dt)) = (now_raw, args[0].1) {
+                    let now_lo = ctx.builder.build_left_shift(now_raw, i64_32, "now_shl");
+                    let now_hi = ctx.builder.build_right_shift(now_raw, i64_32, false, "now_lshr").into();
+                    let now_val = ctx.builder.build_or(now_lo, now_hi, "now_or");
+                    let time = ctx.builder.build_int_add(now_val, dt, "now_add");
+                    let time_hi = ctx.builder.build_int_truncate(ctx.builder.build_right_shift(time, i64_32, false, "now_lshr"), i32_type, "now_trunc");
+                    let time_lo = ctx.builder.build_int_truncate(time, i32_type, "now_trunc");
+                    let now_hiptr = ctx.builder.build_bitcast(now, i32_type.ptr_type(AddressSpace::Generic), "now_bitcast");
+                    if let BasicValueEnum::PointerValue(now_hiptr) = now_hiptr {
+                        let now_loptr = unsafe { ctx.builder.build_gep(now_hiptr, &[i32_type.const_int(1, false).into()], "now_gep") };
+                        ctx.builder.build_store(now_hiptr, time_hi);
+                        ctx.builder.build_store(now_loptr, time_lo);
+                        None
+                    } else {
+                        unreachable!();
+                    }
+                } else {
+                    unreachable!();
+                }
+            }
+        )))
+    )]
+}
+
 #[pymethods]
 impl Nac3 {
     #[new]
@@ -173,107 +275,7 @@ impl Nac3 {
             _ => return Err(exceptions::PyValueError::new_err("invalid ISA")),
         };
         let primitive: PrimitiveStore = TopLevelComposer::make_primitives().0;
-        let mut builtins = vec![];
-        if isa == Isa::RiscV {
-            builtins.push((
-                "now_mu".into(),
-                FunSignature {
-                    args: vec![],
-                    ret: primitive.int64,
-                    vars: HashMap::new(),
-                },
-                Arc::new(GenCall::new(Box::new(
-                    |ctx, _, _, _| {
-                        let i64_type = ctx.ctx.i64_type();
-                        let now = ctx.module.get_global("now").unwrap_or_else(|| ctx.module.add_global(i64_type, None, "now"));
-                        let now_raw = ctx.builder.build_load(now.as_pointer_value(), "now");
-                        if let BasicValueEnum::IntValue(now_raw) = now_raw {
-                            let i64_32 = i64_type.const_int(32, false).into();
-                            let now_lo = ctx.builder.build_left_shift(now_raw, i64_32, "now_shl");
-                            let now_hi = ctx.builder.build_right_shift(now_raw, i64_32, false, "now_lshr").into();
-                            Some(ctx.builder.build_or(now_lo, now_hi, "now_or").into())
-                        } else {
-                            unreachable!()
-                        }
-                    }
-                )))
-            ));
-            builtins.push((
-                "at_mu".into(),
-                FunSignature {
-                    args: vec![FuncArg {
-                        name: "t".into(),
-                        ty: primitive.int64,
-                        default_value: None,
-                    }],
-                    ret: primitive.none,
-                    vars: HashMap::new(),
-                },
-                Arc::new(GenCall::new(Box::new(
-                    |ctx, _, _, args| {
-                        let i32_type = ctx.ctx.i64_type();
-                        let i64_type = ctx.ctx.i64_type();
-                        let i64_32 = i64_type.const_int(32, false).into();
-                        if let BasicValueEnum::IntValue(time) = args[0].1 {
-                            let time_hi = ctx.builder.build_int_truncate(ctx.builder.build_right_shift(time, i64_32, false, "now_lshr"), i32_type, "now_trunc");
-                            let time_lo = ctx.builder.build_int_truncate(time, i32_type, "now_trunc");
-                            let now = ctx.module.get_global("now").unwrap_or_else(|| ctx.module.add_global(i64_type, None, "now"));
-                            let now_hiptr = ctx.builder.build_bitcast(now, i32_type.ptr_type(AddressSpace::Generic), "now_bitcast");
-                            if let BasicValueEnum::PointerValue(now_hiptr) = now_hiptr {
-                                let now_loptr = unsafe { ctx.builder.build_gep(now_hiptr, &[i32_type.const_int(1, false).into()], "now_gep") };
-                                ctx.builder.build_store(now_hiptr, time_hi);
-                                ctx.builder.build_store(now_loptr, time_lo);
-                                None
-                            } else {
-                                unreachable!();
-                            }
-                        } else {
-                            unreachable!();
-                        }
-                    }
-                )))
-            ));
-            builtins.push((
-                "delay_mu".into(),
-                FunSignature {
-                    args: vec![FuncArg {
-                        name: "dt".into(),
-                        ty: primitive.int64,
-                        default_value: None,
-                    }],
-                    ret: primitive.none,
-                    vars: HashMap::new(),
-                },
-                Arc::new(GenCall::new(Box::new(
-                    |ctx, _, _, args| {
-                        let i32_type = ctx.ctx.i64_type();
-                        let i64_type = ctx.ctx.i64_type();
-                        let i64_32 = i64_type.const_int(32, false).into();
-                        let now = ctx.module.get_global("now").unwrap_or_else(|| ctx.module.add_global(i64_type, None, "now"));
-                        let now_raw = ctx.builder.build_load(now.as_pointer_value(), "now");
-                        if let (BasicValueEnum::IntValue(now_raw), BasicValueEnum::IntValue(dt)) = (now_raw, args[0].1) {
-                            let now_lo = ctx.builder.build_left_shift(now_raw, i64_32, "now_shl");
-                            let now_hi = ctx.builder.build_right_shift(now_raw, i64_32, false, "now_lshr").into();
-                            let now_val = ctx.builder.build_or(now_lo, now_hi, "now_or");
-                            let time = ctx.builder.build_int_add(now_val, dt, "now_add");
-                            let time_hi = ctx.builder.build_int_truncate(ctx.builder.build_right_shift(time, i64_32, false, "now_lshr"), i32_type, "now_trunc");
-                            let time_lo = ctx.builder.build_int_truncate(time, i32_type, "now_trunc");
-                            let now_hiptr = ctx.builder.build_bitcast(now, i32_type.ptr_type(AddressSpace::Generic), "now_bitcast");
-                            if let BasicValueEnum::PointerValue(now_hiptr) = now_hiptr {
-                                let now_loptr = unsafe { ctx.builder.build_gep(now_hiptr, &[i32_type.const_int(1, false).into()], "now_gep") };
-                                ctx.builder.build_store(now_hiptr, time_hi);
-                                ctx.builder.build_store(now_loptr, time_lo);
-                                None
-                            } else {
-                                unreachable!();
-                            }
-                        } else {
-                            unreachable!();
-                        }
-                    }
-                )))
-            ));
-        }
+        let builtins = if isa == Isa::RiscV { timeline_builtins(&primitive) } else { vec![] };
         let (composer, builtins_def, builtins_ty) = TopLevelComposer::new(builtins);
         Ok(Nac3 {
             isa,