Adding everything

main.s

@@ -0,0 +1,207 @@
+.intel_syntax noprefix
+.global _start
+
+.data
+welcome: .ascii "Welcome to Brainfuck by cat, written in ASM(GNU)!\nMax char: 65536(incl LF)!\nAllocating memory...\n\0"
+msg2: .ascii "Clearing buffer...\n\0"
+msg3: .ascii "Reading code...\n\0"
+msg4: .ascii "Interpreting...\n\0"
+error_msg_no_path: .ascii "You must specify a path as first argument!!\nAborting!\n\0"
+
+.text
+_start:
+  mov rdi, 1
+  mov rsi, offset welcome
+  call write
+
+  # Is file specified?
+  cmp qword ptr [rsp], 1
+  jle error_no_path
+
+  mov rdi, [rsp+16] # rsp is argc, rsp+8 is argv[0]
+  call open_fd
+  mov rbx, rax      # FD
+
+  # Allocate memory
+  mov rdi, code_max_size
+  call brk_alloc
+  mov r12, rax      # Code heap
+  
+  mov rdi, max_size
+  call brk_alloc
+  mov r13, rax      # Text buffer
+
+  mov rdi, max_size
+  call brk_alloc
+  mov r14, rax      # Cells
+
+  mov rdi, 1
+  mov rsi, offset msg2
+  call write
+
+  # Clear the space
+  mov rdi, r12
+  mov rsi, code_max_size
+  call clear_heap_block
+
+  mov rdi, r13
+  mov rsi, max_size
+  call clear_heap_block
+  
+  mov rdi, r14
+  mov rsi, max_size
+  call clear_heap_block
+
+  mov rdi, 1
+  mov rsi, offset msg3
+  call write
+
+  # Read from file
+  mov rdi, rbx
+  mov rsi, r12
+  mov rdx, code_max_size
+  call read
+
+  mov rdi, 1
+  mov rsi, offset msg4
+  call write
+  # Execution
+  call process_commands
+
+  # Writing result
+  mov rdi, 1
+  mov rsi, r13
+  call write
+
+  # Exiting procedures
+  mov rdi, rbx
+  call close_fd
+
+  xor rdi, rdi
+  call exit
+
+error_no_path:
+  mov rdi, 1
+  mov rsi, offset error_msg_no_path
+  call write
+
+  mov rdi, 1
+  call exit
+
+# r10 text pointer
+# r11 code pointer
+# r12 code
+# r13 text
+# r14 cell
+# r15 cell pointer
+process_commands:
+  xor r11, r11
+  xor r15, r15
+  mov r10, r13
+process_loop:
+  mov r8b, [r12+r11] # Get char
+  call process_symbol
+  inc r11
+  cmp r8b, 0
+  jne process_loop
+  ret
+
+# r8b = char
+process_symbol:
+  cmp r8b, 43 # +
+  je process_inc 
+
+  cmp r8b, 45 # -
+  je process_dec
+
+  cmp r8b, 60 # <
+  je process_back
+  
+  cmp r8b, 62 # >
+  je process_forw
+  
+  cmp r8b, 46 # .
+  je process_prnt
+  
+  cmp r8b, 44 # ,
+  je process_inpt
+
+  cmp r8b, 91 # [
+  je process_loop_start
+
+  cmp r8b, 93 # ]
+  je process_loop_end
+
+  ret
+
+# Ret's here return to process_loop not process_symbol due to Jcc
+process_inc:
+  inc byte ptr [r14+r15]
+  ret 
+
+process_dec:
+  dec byte ptr [r14+r15]
+  ret
+
+# you can't go below or above allocated memory
+process_forw:
+  cmp r15, max_size
+  je 1f
+  inc r15
+1:
+  ret
+
+process_back:
+  cmp r15, 0
+  je 1f
+  dec r15
+1:
+  ret
+
+process_prnt:
+  mov r9b, [r14+r15]
+  mov byte ptr [r10], r9b
+  inc r10
+  ret
+
+process_inpt:
+  mov rdi, r14
+  add rdi, r15
+
+  mov rsi, rdi # char*
+  xor rdi, rdi # fd
+  mov rdx, 1   # size
+  call read
+  ret
+
+# In stack it is 
+# A = Address to loop back
+# C = Cell to check
+# AC AC AC AC AC AC AC <- pop here
+process_loop_start:
+  pop rdi
+  push r11 # Address to loopback
+  push r15 # Cell to check
+  push rdi
+  ret 
+
+process_loop_end:
+  # Gotta get ret value
+  pop rsi
+  pop rdi # Cell
+  pop rax # Address
+  
+  # if cell is 0 we are done with loop
+  cmp byte ptr [r14+rdi], 0
+  je 1f
+  mov r11, rax
+
+  # Make sure stack isn't caught on fire
+  push rax
+  push rdi
+  push rsi
+  ret
+1:
+  push rsi
+  ret # Discard
+