From 7cbef14e8393475b1e569fdbfff2c46db859d43f Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Thu, 4 Nov 2021 11:58:53 +0100
Subject: Add `cons`, `car` and `cdr` primitives

---
 src/x86_64/postlude.asm | 4 ++++
 src/x86_64/prelude.asm  | 7 ++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

(limited to 'src/x86_64')

diff --git a/src/x86_64/postlude.asm b/src/x86_64/postlude.asm
index 3355286..37f9df1 100644
--- a/src/x86_64/postlude.asm
+++ b/src/x86_64/postlude.asm
@@ -9,3 +9,7 @@ exit:
     mov     rax, 60
     xor     rdi, rdi
     syscall
+
+section .bss
+bdl_heap:
+    resb    HEAP_SIZE
diff --git a/src/x86_64/prelude.asm b/src/x86_64/prelude.asm
index 6bb6627..e57e820 100644
--- a/src/x86_64/prelude.asm
+++ b/src/x86_64/prelude.asm
@@ -1,3 +1,4 @@
+section .text
 printdln:
     sar     rdi, FIXNUM_SHIFT
     sub     rsp, 40
@@ -98,4 +99,8 @@ display_end:
 
 global  _start
 _start:
-    push NIL_VAL
+    ;; point `rdi` to the start of the heap.
+    mov     rsi, bdl_heap
+
+    ;; make sure the last element in the stack is the nil value.
+    push    NIL_VAL
-- 
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