Add `cons`, `car` and `cdr` primitives

2 files changed, 10 insertions, 1 deletions

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