From 9f68cbb953980d4bf197684a53b874664a6beb53 Mon Sep 17 00:00:00 2001
From: Tobias Alexandra Platen <alex@platen-software.de>
Date: Sun, 5 Oct 2025 11:04:18 +0200
Subject: [PATCH] add main_memory

---
 crates/cpu/src/lib.rs           |  2 ++
 crates/cpu/src/main_memory.rs   | 62 ++++++++++++++++++++++++++++++++
 crates/cpu/tests/main_memory.rs | 64 +++++++++++++++++++++++++++++++++
 3 files changed, 128 insertions(+)
 create mode 100644 crates/cpu/src/main_memory.rs
 create mode 100644 crates/cpu/tests/main_memory.rs

diff --git a/crates/cpu/src/lib.rs b/crates/cpu/src/lib.rs
index bae3720..c6fd36c 100644
--- a/crates/cpu/src/lib.rs
+++ b/crates/cpu/src/lib.rs
@@ -6,3 +6,5 @@ pub mod reg_alloc;
 pub mod register;
 pub mod unit;
 pub mod util;
+//TODO read other modules
+pub mod main_memory; 
diff --git a/crates/cpu/src/main_memory.rs b/crates/cpu/src/main_memory.rs
new file mode 100644
index 0000000..f386061
--- /dev/null
+++ b/crates/cpu/src/main_memory.rs
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+// first copied code block -- changes needed
+use crate::{
+    config::CpuConfig,
+    instruction::{
+        AluBranchMOp, LoadStoreMOp, MOp, MOpDestReg, MOpInto, MOpRegNum, MOpTrait, RenamedMOp,
+        UnitOutRegNum, mop_enum,
+    },
+    register::{FlagsMode, PRegValue},
+    unit::unit_base::UnitToRegAlloc,
+};
+use fayalite::{
+    bundle::{Bundle, BundleType},
+    intern::{Intern, Interned},
+    prelude::*,
+};
+
+//input address <32> bit ?
+//output data word <8> bit for first test (read only)
+
+#[hdl_module]
+/// add a comment here
+pub fn main_memory(config: &CpuConfig) {
+    #[hdl]
+    let addr: UInt<64> = m.input();
+    #[hdl]
+    let read_data: UInt<8> = m.output();
+    #[hdl]
+    let en: Bool = m.input();
+    
+	#[hdl]
+    let cd: ClockDomain = m.input();
+    // for each instance do
+    // connect(instance.cd, cd);
+    
+    
+    #[hdl] 
+    //let mut mem = memory_with_init([0x12u8, 0x34, 0x56, 0x78]);
+    let mut my_memory = memory_with_init([0x12_hdl_u8, 0x34_hdl_u8, 0x56_hdl_u8, 0x78_hdl_u8]);
+
+    let read_port = my_memory.new_read_port();
+    // note that `read_addr` is `UInt<2>` since the memory only has 4 elements
+    //need to connect addr en clk and data->out
+    connect_any(read_port.addr, addr); //FIXME
+    connect(read_port.en, en);
+    connect(read_port.clk, cd.clk);
+    connect(read_data,read_port.data);
+
+    
+
+
+}
+
+// see https://git.libre-chip.org/libre-chip/fayalite/src/branch/master/crates/fayalite/tests/sim.rs
+// how to write testbenches
+// start with a very simple memory model -> 
+// TODO create a branch for the memory 
+
+// 1 connect up the read port, add write later
+// ask how I make the memory pipelined later ... not today
diff --git a/crates/cpu/tests/main_memory.rs b/crates/cpu/tests/main_memory.rs
new file mode 100644
index 0000000..4792bef
--- /dev/null
+++ b/crates/cpu/tests/main_memory.rs
@@ -0,0 +1,64 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// See Notices.txt for copyright information
+
+use cpu::{
+    config::{CpuConfig, UnitConfig},
+    instruction::{AddSubMOp, LogicalMOp, MOp, MOpDestReg, MOpRegNum, OutputIntegerMode},
+    reg_alloc::{FetchedDecodedMOp, reg_alloc},
+    register::{FlagsMode, PRegFlagsPowerISA},
+    unit::{GlobalState, UnitKind},
+    main_memory::main_memory,
+};
+use fayalite::{
+    assert_export_firrtl,
+    firrtl::ExportOptions,
+    prelude::*,
+    sim::{Simulation, time::SimDuration, vcd::VcdWriterDecls},
+    util::RcWriter,
+};
+use std::num::NonZeroUsize;
+
+#[hdl]
+#[test]
+fn test_main_memory() {
+// see reg_alloc.rs for reference
+	let _n = SourceLocation::normalize_files_for_tests();
+    let mut config = CpuConfig::new(
+        vec![
+            UnitConfig::new(UnitKind::AluBranch),
+            UnitConfig::new(UnitKind::AluBranch),
+        ],
+        NonZeroUsize::new(20).unwrap(),
+    );
+    config.fetch_width = NonZeroUsize::new(2).unwrap(); //unchanged for now
+    let m = main_memory(&config);
+    let mut sim = Simulation::new(m);
+    let mut writer = RcWriter::default();
+    sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
+    sim.write_clock(sim.io().cd.clk, false);
+    sim.write_reset(sim.io().cd.rst, true);
+    //TODO sim.write_bool
+    //TODO sim.write(
+    //footer for tests
+    // FIXME: vcd is just whatever reg_alloc does now, which isn't known to be correct
+    let vcd = String::from_utf8(writer.take()).unwrap();
+    println!("####### VCD:\n{vcd}\n#######");
+    //if vcd != include_str!("expected/reg_alloc.vcd") { //FIXME panic on result compare
+    //    panic!();  //test is incomplete here, getting panic
+    //}
+    // #[rustfmt::skip] // work around https://github.com/rust-lang/rustfmt/issues/6161
+    // assert_export_firrtl! {
+    //     m =>
+    //     options: ExportOptions {
+    //         simplify_enums: None,
+    //         ..ExportOptions::default()
+    //     },
+    //     "/test/reg_alloc.fir": "",
+    // };
+    // let sim_debug = format!("{sim:#?}");
+    // println!("#######\n{sim_debug}\n#######");
+    // if sim_debug != include_str!("expected/reg_alloc.txt") {
+    //     panic!();
+    // }
+    
+}