do awaiting labels, fix bug, make call not crash xd

twasm/asm/main.asm

@@ -63,6 +63,9 @@ start:
   pop rdi ; rdi = number of tokens in token table
   call assemble
 
+  mov rsi, msg_welcome
+  call OUTPUT_ADDR
+
   jmp halt
 
 ; ------------------------------------------------------------------------------
@@ -941,7 +944,7 @@ assemble:
     call print.debug
     pop rsi
     mov rsp, rbp
-    ret
+    jmp resolve_awaiting_labels ; tail call
 
   .unexpected_token:
     call .flush_write_buffer
@@ -1075,6 +1078,70 @@ assemble:
   .msg_operator_2_register_const db "operator_2_register_const", 0x0A, 0x00
   .msg_pseudo_operator db "pseudo_operator", 0x0A, 0x00
 
+; ------------------------------------------------------------------------------
+; resolve_awaiting_labels
+;
+; description:
+; resolves placeholder references in the program at OUTPUT_ADDR using the
+; label table and awaiting label table
+; ------------------------------------------------------------------------------
+
+resolve_awaiting_labels:
+  mov rbp, rsp
+  xor eax, eax
+  .loop:
+    shl rax, 4
+    mov rdi, [AWAITING_LABEL_TABLE_ADDR + rax]
+    ; rdi = raxth hash in awaiting label table
+
+    cmp rdi, 0
+    je .break
+
+    mov rsi, .msg
+    call print.warn
+
+    push rax
+    ; rdi = raxth hash in awaiting label table
+    call add_label_hash
+    ; rax = index in label table
+    shl rax, 4
+    mov edi, [LABEL_TABLE_ADDR + rax + 8] ; edi = address of label
+    pop rax ; rax = count
+
+    mov esi, [AWAITING_LABEL_TABLE_ADDR + rax + 8] ; esi = address of reference
+
+    sub edi, esi ; edi = offset
+    ; TODO fix this off-by-one error
+    dec edi
+    ; also sub length of reference TODO handle non-4-length refs 
+    sub edi, 4
+
+    mov dl, [AWAITING_LABEL_TABLE_ADDR + rax + 12] ; dl = flags
+
+    ; make sure it's 4 byte reference
+    push rdx
+    and dl, 0x0F
+    cmp dl, 4
+    pop rdx
+    jne .break
+
+    ; make sure it's relative reference
+    push rdx
+    and dl, 0x10
+    cmp dl, 0x00
+    pop rdx
+    jne .break
+
+    mov [OUTPUT_ADDR + 1 + rsi], edi
+
+    shr rax, 4
+    inc rax
+    jmp .loop
+  .break:
+    mov rsp, rbp
+    ret
+  .msg db "resolve_awaiting_labels", 0x0A, 0x00
+
 ; ------------------------------------------------------------------------------
 ; get_tte_type
 ;
@@ -2392,7 +2459,7 @@ add_awaiting_label:
     mov rdx, [LABEL_TABLE_ADDR + rdi]
     mov [AWAITING_LABEL_TABLE_ADDR + rax], rdx ; hash
     mov [AWAITING_LABEL_TABLE_ADDR + 8 + rax], esi ; address
-    mov [AWAITING_LABEL_TABLE_ADDR + 13 + rax], cl ; bits passed to al
+    mov [AWAITING_LABEL_TABLE_ADDR + 12 + rax], cl ; bits passed to al
     ret
 
 ; ------------------------------------------------------------------------------
@@ -3169,6 +3236,7 @@ whitespace_2 db " ", 0x0D
 ; test program
 align 128
 program:
+  db "ret", 0x0A
   db "print:", 0x0A
   db "  push rdx", 0x0A
   db "  push rax", 0x0A