diff --git a/nac3artiq/src/builtins.rs b/nac3artiq/src/builtins.rs
new file mode 100644
index 00000000..a9cb4485
--- /dev/null
+++ b/nac3artiq/src/builtins.rs
@@ -0,0 +1,167 @@
+use inkwell::{values::BasicValueEnum, AddressSpace, AtomicOrdering};
+use nac3core::{
+    toplevel::GenCall,
+    typecheck::{
+        type_inferencer::PrimitiveStore,
+        typedef::{FunSignature, FuncArg},
+    },
+};
+use rustpython_parser::ast::StrRef;
+use std::{collections::HashMap, sync::Arc};
+
+// ARTIQ timeline control with now-pinning optimization.
+pub 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.i32_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)
+                            .set_atomic_ordering(AtomicOrdering::SequentiallyConsistent)
+                            .unwrap();
+                        ctx.builder
+                            .build_store(now_loptr, time_lo)
+                            .set_atomic_ordering(AtomicOrdering::SequentiallyConsistent)
+                            .unwrap();
+                        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.i32_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)
+                            .set_atomic_ordering(AtomicOrdering::SequentiallyConsistent)
+                            .unwrap();
+                        ctx.builder
+                            .build_store(now_loptr, time_lo)
+                            .set_atomic_ordering(AtomicOrdering::SequentiallyConsistent)
+                            .unwrap();
+                        None
+                    } else {
+                        unreachable!();
+                    }
+                } else {
+                    unreachable!();
+                }
+            }))),
+        ),
+    ]
+}