split into multiple files, .o files in build/

1 files changed, 70 insertions, 72 deletions

diff --git a/main.asm b/main.asm
index d1f424c..f20699a 100644
--- a/main.asm
+++ b/main.asm
@@ -1,99 +1,97 @@
 section .data
-    clear db 0x1B, '[2J', 0x1B, '[H', 0
-    clear_len equ $ - clear 
+
+    ; cursor management
+    reset_cursor db 0x1B , '[H', 0
+    reset_cursor_len equ $ - reset_cursor
+    up_cursor db 0x1B , '[A', 0
+    up_cursor_len equ $ - up_cursor
+    bottom_cursor db 0x1B , '[B', 0
+    bottom_cursor_len equ $ - bottom_cursor
+    right_cursor db 0x1B , '[C', 0
+    right_cursor_len equ $ - right_cursor
+    left_cursor db 0x1B , '[D', 0
+    left_cursor_len equ $ - left_cursor
+
+    ; example messages for later
     message1 db "Hello, World!", 0xA
     msg_len1 equ $ - message1          
     message2 db "Hello 2!", 0xA  
     msg_len2 equ $ - message2
+    
+    ; array of snake - 1000 thousand bytes means max length is 500
+    ; head is at snake[0]
+    snake TIMES 1000 db 0
+
+    ; direction of the snake:
+    ;   3
+    ; 2 x 0
+    ;   1
+    direction db 0
+
+section .bss
+    buffer resb 1
 
 section .rodata
+    ; width and height of the playable area
+    ; (without the borders)
+    global width
+    global height
     width db 70
     height db 30
 
-section .bss
-    byte_to_write resb 1
-
 section .text
+    extern draw_border
+    extern write_byte
+    extern clear_screen
     global _start 
 
-write_byte:
-    push rdi
-    mov byte [byte_to_write], al
-    mov rax, 1                      
-    mov rdi, 1                      
-    mov rsi, byte_to_write                
-    mov rdx, 1                
-    syscall                         
-    pop rdi
-    ret
-
-clear_screen:
-    push rdi
-    mov rax, 1                      
-    mov rdi, 1                      
-    mov rsi, clear                
-    mov rdx, clear_len                
-    syscall                         
-    pop rdi
-    ret
-
-draw_upper_lower_line:
+draw_snake:
     push rbx
-    mov rax, '+'
-    call write_byte
-    mov bl, byte [width]
-_01:mov rax, '-'
-    call write_byte
-    dec bl
-    cmp bl, 0
-    jnz _01
-    mov rax, '+'
-    call write_byte
-    mov rax, 10 ;newline
-    call write_byte
-    pop rbx
-    ret
+    mov bh, byte [snake]
+    mov bl, byte [snake+1]
+_10:
 
-draw_left_right_lines:
-    push rbx
-    mov rax, '|'
-    call write_byte
-    mov bl, byte [width]
-_02:mov rax, 32 ;space
-    call write_byte
-    dec bl
-    cmp bl, 0
-    jnz _02
-    mov rax, '|'
-    call write_byte
-    mov rax, 10;newline
-    call write_byte
     pop rbx
     ret
 
-draw_border:
-    push rbx
-
-    call draw_upper_lower_line
-    mov bl, byte [height]
-_03:call draw_left_right_lines
-    dec bl
-    cmp bl, 0
-    jnz _03
+_start:
+    call clear_screen
+    call draw_border
 
-    call draw_upper_lower_line
+    mov byte [snake], 5
+    mov byte [snake+1], 5
 
-    pop rbx
-    ret
+    mov rax, 1                      
+    mov rdi, 1                      
+    mov rsi, reset_cursor                
+    mov rdx, reset_cursor_len                
+    syscall                         
+    mov rax, 1                      
+    mov rdi, 1                      
+    mov rsi, bottom_cursor                
+    mov rdx, bottom_cursor_len                
+    syscall                         
+    mov rax, 1                      
+    mov rdi, 1                      
+    mov rsi, right_cursor                
+    mov rdx, right_cursor_len                
+    syscall                         
 
+    mov rax, 0           ; Syscall for read
+    mov rdi, 0           ; stdin
+    mov rsi, buffer      ; Address of the buffer
+    mov rdx, 1           ; Read 1 byte
+    syscall
 
-_start:
-    call clear_screen
-    call draw_border
+    ; If a key was pressed, store it in `input`
+    test rax, rax        ; Check if any input was received
+    jz exit         ; If no input, skip
+    mov al, byte [buffer]; Load the input character
 
+    ;mov rax, 'x'
+    call write_byte
 
-exit:
-    ; exit syscall with return code 0
+exit: ; exit syscall with return code 0
     mov rax, 60                     
     xor rdi, rdi                    
     syscall