make game loop: head is moving to the right

2 files changed, 91 insertions, 40 deletions

diff --git a/main.asm b/main.asm
index f20699a..1ba1eb5 100644
--- a/main.asm
+++ b/main.asm
@@ -1,17 +1,5 @@
 section .data
 
-    ; 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          
@@ -19,7 +7,8 @@ section .data
     msg_len2 equ $ - message2
     
     ; array of snake - 1000 thousand bytes means max length is 500
-    ; head is at snake[0]
+    ; x head is at snake[0]
+    ; y head is at snake[1]
     snake TIMES 1000 db 0
 
     ; direction of the snake:
@@ -28,6 +17,9 @@ section .data
     ;   1
     direction db 0
 
+    timespec dq 0 
+             dq 500000000
+
 section .bss
     buffer resb 1
 
@@ -43,53 +35,65 @@ section .text
     extern draw_border
     extern write_byte
     extern clear_screen
+    extern reset_cursor
+    extern move_cursor_right
+    extern move_cursor_down
     global _start 
 
 draw_snake:
     push rbx
+    call reset_cursor
     mov bh, byte [snake]
     mov bl, byte [snake+1]
-_10:
+
+_10:call move_cursor_right
+    dec bh
+    cmp bh, 0
+    jnz _10
+_11:call move_cursor_down
+    dec bl
+    cmp bl, 0
+    jnz _11
+
+    mov rax, 'x'
+    call write_byte
 
     pop rbx
+    call reset_cursor
     ret
 
 _start:
-    call clear_screen
-    call draw_border
-
     mov byte [snake], 5
     mov byte [snake+1], 5
 
-    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                         
+main_loop:
+    call clear_screen
+    call draw_border
+    call draw_snake
 
-    mov rax, 0           ; Syscall for read
-    mov rdi, 0           ; stdin
-    mov rsi, buffer      ; Address of the buffer
-    mov rdx, 1           ; Read 1 byte
+    lea rdi, [timespec]    ; Pointer to timespec struct (rdi)
+    xor rsi, rsi           ; NULL (no remaining time)
+    mov rax, 35            ; Syscall number for nanosleep
     syscall
 
+    inc byte [snake]
+
+    jmp main_loop
+
+;    mov rax, 0           ; Syscall for read
+;    mov rdi, 0           ; stdin
+;    mov rsi, buffer      ; Address of the buffer
+;    mov rdx, 1           ; Read 1 byte
+;    syscall
+
     ; 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
+;    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
+;    call write_byte
 
 exit: ; exit syscall with return code 0
     mov rax, 60                     
diff --git a/utils.asm b/utils.asm
index 39a2df3..7c7dc31 100644
--- a/utils.asm
+++ b/utils.asm
@@ -3,6 +3,14 @@ section .data
     clear db 0x1B, '[2J', 0x1B, '[H', 0
     clear_len equ $ - clear 
 
+    ; cursor management
+    reset_cursor_code db 0x1B , '[H', 0
+    reset_cursor_len equ $ - reset_cursor_code
+    bottom_cursor db 0x1B , '[B', 0
+    bottom_cursor_len equ $ - bottom_cursor
+    right_cursor db 0x1B , '[C', 0
+    right_cursor_len equ $ - right_cursor
+
 section .bss
     ; adress for syscall for write_byte wrapper
     byte_to_write resb 1
@@ -10,6 +18,45 @@ section .bss
 section .text
     global write_byte
     global clear_screen
+    global move_cursor_right
+    global move_cursor_down
+    global reset_cursor
+
+reset_cursor:
+    push rdi
+    
+    mov rax, 1                      
+    mov rdi, 1                      
+    mov rsi, reset_cursor_code 
+    mov rdx, reset_cursor_len                
+    syscall                         
+
+    pop rdi
+    ret
+
+move_cursor_right:
+    push rdi
+
+    mov rax, 1
+    mov rdi, 1
+    mov rsi, right_cursor
+    mov rdx, right_cursor_len
+    syscall
+
+    pop rdi
+    ret
+
+move_cursor_down:
+    push rdi
+
+    mov rax, 1
+    mov rdi, 1
+    mov rsi, bottom_cursor
+    mov rdx, bottom_cursor_len
+    syscall
+
+    pop rdi
+    ret
 
 write_byte:
     push rdi