init stack vec, push rplogue

lang/src/codegen.asm

@@ -5,6 +5,7 @@ default rel
 extern panic
 extern vec_extend
 extern vec_get
+extern vec_init_with
 
 global codegen_function
 
@@ -17,8 +18,37 @@ section .rdata
     COLON_NL_LEN equ $ - COLON_NL
     RET_NL db "ret", 10
     RET_NL_LEN equ $ - RET_NL
+    PROLOGUE db "push rbp", 10, "mov rbp, rsp", 10
+    PROLOGUE_LEN equ $ - PROLOGUE
 
 section .text
+
+
+;; rdi: ctx
+;; rsi: a: *const (index, offset)
+;; rdx: b: *const (index, offset)
+;; define-fn: fn stackvar_cmp(a: *const (u64, u64), b: *const (u64, u64)) -> i32
+stackvar_cmp:
+    push rbp
+    mov rbp, rsp
+
+    mov rax, [rdi + 0]      ; a.index
+    mov rcx, [rsi + 0]      ; b.index
+    cmp rax, 0
+    jl .less
+    jg .greater
+    xor rax, rax
+    jmp .done
+.less:
+    mov rax, -1
+    jmp .done
+.greater:
+    mov rax, 1
+
+.done:
+    pop rbp
+    ret
+
 ;; start-structs
 ;; struct CodegenCtx {
 ;;   ast: *const Ast,
@@ -45,9 +75,16 @@ codegen_function:
     mov rax, [rdi]
     mov [rsp + 8], rax          ; ast
     mov [rsp + 16], rsi         ; func_idx
+    mov [rsp + 24], 0           ; current_stack_size = 0
 
-    bts qword [rsp + 72], 7           ; mark rbp as used
+    lea rdi, [rsp + 32]         ; stack-vars
-    bts qword [rsp + 72], 6           ; mark rsp as used
+    mov rsi, 16                 ; size_of::<(u64, u64)>
+    mov rdx, 0                  ; drop = None
+    mov rcx, 16                 ; initial capacity
+    call vec_init_with
+
+    bts qword [rsp + 72], 7     ; mark rbp as used
+    bts qword [rsp + 72], 6     ; mark rsp as used
 
     ; push "section .text\n"
     mov rdi, [rsp]              ; ctx
@@ -94,7 +131,13 @@ codegen_function:
     lea rsi, [rel COLON_NL]
     mov rdx, 2
     call vec_extend
-    
+
+    ; push prologue
+    mov rdi, [rsp]              ; ctx
+    lea rdi, [rdi + 8]          ; &ctx.text
+    lea rsi, [rel PROLOGUE]
+    mov rdx, PROLOGUE_LEN
+    call vec_extend
 
     ; TODO: generate function body