From 6dff42cfa5cbcbe832107be1fb04d23f6993a2d1 Mon Sep 17 00:00:00 2001
From: janis <janis@nirgendwo.xyz>
Date: Sun, 2 Nov 2025 16:49:46 +0100
Subject: [PATCH] var decl/ varref codegen

---
 lang/src/codegen.asm | 77 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 72 insertions(+), 5 deletions(-)

diff --git a/lang/src/codegen.asm b/lang/src/codegen.asm
index 5cf1f8d..2bafc2f 100644
--- a/lang/src/codegen.asm
+++ b/lang/src/codegen.asm
@@ -8,6 +8,7 @@ extern vec_extend
 extern vec_get
 extern vec_push
 extern vec_insert_sorted
+extern vec_binary_search_by
 extern vec_insert_many
 extern vec_init_with
 extern int_to_str2
@@ -967,8 +968,9 @@ codegen_expr:
     ; function_ctx: [8..16]
     ; ctx [0..8]
     sub rsp, 80
-    mov [rsp], rdi          ; ctx
-    mov [rsp + 8], rsi    ; &function_ctx
+    mov [rsp], rdi              ; ctx
+    mov [rsp + 8], rsi          ; &function_ctx
+    mov [rsp + 16], rdx         ; expr index
 
     mov rdi, [rdi]              ; ast
     mov rsi, rdx                ; statement index
@@ -1241,12 +1243,13 @@ codegen_expr:
     lea rdx, [rsp + 64]         ; scratch value
     call codegen_move_dst_src
 
-.after_unspill_rdx:
-    ; free [scratch, rhs, lhs]
+    ; free scratch
     mov rdi, [rsp + 8]          ; &function_ctx
     lea rsi, [rsp + 64]         ; scratch value
     call codegen_free_operand
 
+.after_unspill_rdx:
+    ; free  [rhs, lhs]
     mov rdi, [rsp + 8]          ; &function_ctx
     lea rsi, [rsp + 48]         ; right operand
     call codegen_free_operand
@@ -1286,9 +1289,70 @@ codegen_expr:
     jmp .done
 
 .var_decl:
+    ; allocate place for variable
+    mov rdi, [rsp + 8]          ; &function_ctx
+    mov rsi, 8                  ; size_of::<u64>
+    call codegen_allocate_place
+    mov [rsp + 64], rax         ; Operand
+    mov [rsp + 72], rdx         ; Operand.value
+    neg rdx
+    mov [rsp + 24], rdx        ; &(_, offset)
+
+    mov rdi, [rsp + 8]         ; &function_ctx
+    lea rdi, [rsp + 8]         ; stack_vars
+    lea rsi, [rsp + 16]        ; &(index, offset)
+    mov rdx, stackvar_cmp
+    mov rcx, 0
+    call vec_insert_sorted
+
+    mov rax, [rsp + 64]         ; Operand
+    mov rdx, [rsp + 72]         ; Operand.value
+    jmp .done
+
 .var_ref:
-.assignment:
+    mov rax, [rax + 8]          ; AstNode.data
+    mov rax, [rax]              ; variable index
+
+    mov [rsp + 16], rax
+    mov qword [rsp + 24], 0
+    ; lookup variable in stack_vars
+
+    mov rdi, [rsp + 8]          ; &function_ctx
+    lea rdi, [rdi + 8]          ; stack_vars
+    lea rsi, [rsp + 16]         ; &(index, offset)
+    mov rdx, stackvar_cmp
+    mov rcx, 0
+    call vec_binary_search_by
+    cmp rdx, 1
+    je .panic                   ; variable not found
+
+    mov rdi, [rsp + 8]          ; &function_ctx
+    lea rdi, [rdi + 8]          ; stack_vars
+    mov rsi, rax                ; index
+    call vec_get
+    mov rdx, [rax + 8]          ; offset
+    neg rdx
+    mov rax, qword [rel OPERAND_RBP_OFFSET]
+    mov [rsp + 16], rax
+    mov [rsp + 24], rdx
+
+    ; allocate value (?)
+    mov rdi, [rsp + 8]          ; &function_ctx
+    mov rsi, 8                  ; width = size_of::<* const()>
+    call codegen_allocate_value
+    mov [rsp + 32], rax         ; dst
+    mov [rsp + 40], rdx
+
+    ; lea dst, [rbp - offset]
+    mov rdi, [rsp]              ; ctx
+    lea rsi, [rdi + 8]          ; &ctx.text
+    mov rdi, [rsp + 8]          ; &function_ctx
+    lea rdx, [rsp + 32]         ; dst
+    lea rcx, [rsp + 16]         ; src
+    mov r8, 'lea '
+    call codegen_binary_op_rm64_rm64
 .place_to_value:
+.assignment:
 .value_to_place:
 .deref:
 .address_of:
@@ -1875,4 +1939,7 @@ section .rdata
     ; Operand { kind: REGISTER, register: 0, width: 8, len: 0, padding: 0, value: 0 }
     align 8
     OPERAND_RAX dq 0x0000_8001, 0
+    align 8
     OPERAND_RDX dq 0x0000_8301, 0
+    align 8
+    OPERAND_RBP_OFFSET dq 0x0000_8002, 0