replace %d with 666 kinda works

src/macros.asm

@@ -50,19 +50,20 @@
     ; printdf [format str] [int]
     push_registers
 
+    ; TODO: do not segfault when we write out of those bounds
+    %define MAX_PRINTF_LEN 2048
+
     ; rax = is null terminated format str
     str_to_stack %1
 
-    %define MAX_PRINTF_LEN 10
-
     sub rsp, MAX_PRINTF_LEN
     ; r10 is index in final output string
     mov r10, 0
     ; r11 is pointer to start of output string
     lea r11, [rbp-MAX_PRINTF_LEN]
 
     mov rcx, 0
-.printf_fmt_char_loop:
+%%printf_fmt_char_loop:
     mov r9b, byte [rax+rcx]
     inc rcx
 
@@ -71,15 +72,42 @@
     mov byte [r11+r10], r9b
     inc r10
 
+    cmp r9b, '%'
+    jne %%printf_fmt_char_loop_check_repeat
+
+%%printf_fmt_char_loop_got_percentage:
+    mov r9b, byte [rax+rcx]
+    cmp r9b, 'd'
+    jne %%printf_fmt_char_loop_check_repeat
+
+%%printf_fmt_char_loop_got_fmt_d:
+
+    ; overwrite the %d
+    dec r10
+    inc rcx
+
+    mov byte [r11+r10], '6'
+    inc r10
+    mov byte [r11+r10], '6'
+    inc r10
+    mov byte [r11+r10], '6'
+    inc r10
+
+%%printf_fmt_char_loop_check_repeat:
+
     cmp r9b, 0
-    jne .printf_fmt_char_loop
+    jne %%printf_fmt_char_loop
 
     ; print output buffer
     printn r11, r10
 
     ; frees stack string
     ; and copy buffer
     mov rsp, rbp
+
+    ; TODO: support \n escape sequence
+    call print_newline
+
     pop_registers
 %endmacro