From f7d49ec7b506417b10e77ba0d373d85d243c3ed5 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <andrew@subarctic.org>
Date: Mon, 1 Jan 2024 17:05:49 -0700
Subject: [PATCH] print atom is working along with hello world

---
 .cargo/config.toml |  3 +++
 src/g.rs           |  4 +---
 stdlib/prelude.lm  | 21 ++++++++++++++++++++-
 3 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 .cargo/config.toml

diff --git a/.cargo/config.toml b/.cargo/config.toml
new file mode 100644
index 000000000..17871dde2
--- /dev/null
+++ b/.cargo/config.toml
@@ -0,0 +1,3 @@
+
+[env]
+RUST_TEST_THREADS = "1"
diff --git a/src/g.rs b/src/g.rs
index a9403f358..291ff39d3 100644
--- a/src/g.rs
+++ b/src/g.rs
@@ -97,7 +97,7 @@ fn compile_expr(helpers_ctx: &S, program_ctx: &S, e: &S) -> S {
       let xpg = compile_expr(helpers_ctx, program_ctx, &x);
       assert_eq!( head(&f).to_string(), "variable" );
       let f_name = label_case( &tail(&f).to_string() );
-      let call = variable( &format!("\tjmp {}\n", f_name) );
+      let call = variable( &format!("\tcall {}\n", f_name) );
       let prog = app(
          head(&xpg),
          call
@@ -152,8 +152,6 @@ pub fn compile(cfg: &str, main_ctx: &S) {
    for (k,v) in kv_iter(&main_ctx) {
       let k = k.to_string();
       let v = compile_expr(&helpers_ctx, &main_ctx, &v);
-      println!("compile user {} = {}", k, v);
-      println!("compile user {} = {}", k, head(&v));
       raw_program = app(
          raw_program,
          app(
diff --git a/stdlib/prelude.lm b/stdlib/prelude.lm
index 5859eaaa9..667338c56 100644
--- a/stdlib/prelude.lm
+++ b/stdlib/prelude.lm
@@ -1,5 +1,18 @@
 
 .text := (
+   # internal strlen (%rdi: *char)
+   _strlen:                    \n
+   \t xor %rcx, %rcx           \n
+   _strlen_loop:               \n
+   \t cmpb $0, 0(%rdi)         \n
+   \t jz _strlen_exit          \n
+   \t inc %rcx                 \n
+   \t inc %rdi                 \n
+   \t jmp  _strlen_loop        \n
+   _strlen_exit:               \n
+   \t ret                      \n
+   # result is stored in %rcx
+
    # entry points
    print_s:                    \n
    __print_this:               \n
@@ -8,7 +21,13 @@
    __print_this_atom:          \n
    \t cmp $0, %r8              \n
    \t je __print_this_cons     \n
-   # TODO print .atom
+   \t mov %r8, %rdi            \n
+   \t call _strlen             \n
+   \t mov %r8, %rsi            \n   # address of string to output
+   \t mov %rcx, %rdx           \n   # length is %rcx
+   \t mov $1, %rax             \n   # system call 1 is write
+   \t mov $1, %rdi             \n   # file handle 1 is stdout
+   \t syscall                  \n   # invoke operating system to do the write
    \t ret                      \n
 
    __print_this_cons:          \n