count words

lang/Makefile

@@ -1,9 +1,16 @@
-SRC := asem.s
-
+SRCDIR := src
+SRC := $(addprefix $(SRCDIR)/, $(addsuffix .s, asem balloc split))
 
 OBJDIR := obj
-OBJ := $(OBJDIR)/$(SRC:.s=.o)
+OBJ := $(addprefix $(OBJDIR)/, $(notdir $(SRC:.s=.o)))
 
-all: 
-	nasm -felf64 -g $(SRC) -o $(OBJ)
+$(shell mkdir -p $(OBJDIR))
+
+all: $(OBJ) 
 	ld -o debug $(OBJ) -nostdlib -static
+
+$(OBJDIR)/%.o: $(SRCDIR)/%.s
+	nasm -felf64 -g $< -o $@
+
+clean:
+	rm -rf $(OBJDIR) debug

lang/asem.s

@@ -1,49 +0,0 @@
-%define DEF_BUFFER_LEN 4096
-%define INPUT_LENGTH 64
-
-; rax -- syscall
-
-; type widths
-
-section .data
-    message:        db      "Hello World!", 0xA, 0 ; hello
-    message_length: equ     $-message
-
-section .bss
-    arr:            resb DEF_BUFFER_LEN
-
-section .text
-    global  _start
-
-print_string:
-    push rbp
-    push rdx
-    mov rbp, rsp    ; set up stack frame
-
-    mov rax, 1      ; sys_write
-
-    pop rdx
-    pop rbp
-
-exit:
-    mov     rax, 60
-    syscall
-
-strlen:
-    push rcx
-    xor rcx, rcx
-.loop:
-    cmp byte [rdi + rcx], 0
-    jz  .done
-    inc rcx
-    jmp .loop
-.done:
-    mov rax, rcx
-    pop rcx
-    ret
-
-_start:
-    mov rdi, message    ; prepare first arg -> string addr to rdi
-    call strlen
-    mov rdi, rax
-    call exit

lang/src/asem.s

@@ -0,0 +1,100 @@
+%define DEF_BUFFER_LEN 4096
+%define INPUT_LENGTH 64
+
+extern split
+
+section .data
+    message:        db      "Hello World!", 0xA, 0
+    message_length: equ     $-message
+    filepath:       db      "./test.c"
+
+section .bss
+    file_content_buffer:    resb DEF_BUFFER_LEN
+
+section .text
+    global  _start
+
+open_file:
+    mov rax, 2          ; sys_open
+
+    syscall
+    ret
+
+close_file:
+    mov rax, 3         ; sys_close
+
+    syscall
+    ret
+
+read_file_bytes:    ; read(RDI: int fd, RSI: char *buffer, RDX: size_t size)
+    mov rax, 0      ; sys_read
+    syscall         ;
+    ret
+
+print_string:       ; print_string(RDI: char *string)
+    call strlen
+
+    mov rdx, rax    ; string length
+
+    mov rsi, rdi
+    mov rdi, 1      ; stdout
+    mov rax, 1      ; sys_write
+    syscall
+
+    ret
+
+exit:
+    mov     rax, 60
+    syscall
+
+strlen:                 ; strlen(RDI: char *str)
+    push rcx            ; save counter
+    xor rcx, rcx
+.loop:                  ; loop until '\0' character
+    cmp byte [rdi + rcx], 0
+    jz  .done
+    inc rcx
+    jmp .loop
+.done:
+    mov rax, rcx        ; mov return value to rax
+    pop rcx             ; restore counter
+    ret
+
+_start:
+    mov rdi, message    ; prepare first arg -> string addr to rdi
+    call print_string
+
+    mov rdi, rax
+    push rax            ; save rax
+    push rdi            ; save rdi since arg comes into it
+
+    mov rdi, filepath   ; filepath for open call
+    mov rsi, 0          ; O_RDONLY flag
+    call open_file
+
+    mov rbx, rax        ; mov new fd to rbx
+
+    mov rdi, rbx        ; first arg: mov fd to rdi for read call
+    mov rsi, file_content_buffer    ; 2nd arg: buffer
+    mov rdx, 15         ; 3rd arg: read len
+
+    call read_file_bytes
+    mov byte [file_content_buffer + 15], 0xA   ; newline
+    mov byte [file_content_buffer + 16], 0x0   ; 0 terminate string
+
+    push rdi            ; save fd
+    mov rdi, rsi          ; stdout fd
+
+    call print_string
+    pop rdi             ; restore fd
+
+    call close_file
+
+    mov rdi, rsi
+    mov rsi, 0x20       ; ' ' space character
+    call split
+
+.exit_early:
+    mov rdi, rax
+
+    call exit

lang/src/balloc.s

@@ -0,0 +1,26 @@
+global balloc
+
+brk_find_break:     ; RAX: long brk(0)
+    mov rdi, 0x0
+    mov rax, 0xC    ; sys_brk
+    syscall
+    ret
+
+balloc:                 ; RAX: long basic_malloc(RDI: size_t n, RSI void **heap_begin_ptr)
+    cmp dword [rsi], 0        ; check if heap_begin_ptr exist
+    jne .allocate       ; allocate normally if exists
+
+    push rdi
+
+    call brk_find_break
+
+    mov qword [rsi], rax        ; get heap beginning
+    pop rdi
+
+.allocate:
+    mov rax, qword [rsi]
+    add rdi, rax
+    mov rax, 0xC        ; sys_brk
+
+    syscall
+    ret

lang/src/split.s

@@ -0,0 +1,43 @@
+global  split   ; export split
+
+section .text
+
+count_splits:   ; RAX: int count_splits(RDI: char *, RSI: int c)
+    push rbx
+    xor rcx, rcx
+    xor rbx, rbx
+.loop:
+    cmp byte [rdi + rcx], 0
+    jz  .done
+    cmp byte [rdi + rcx], sil
+    jne .skip
+    inc rbx
+.skip:
+    inc rcx
+    jmp .loop
+.done:
+    mov rax, rbx
+    pop rbx
+    ret
+
+split:          ; RAX: char ** split(RDI: char *str, RSI: int c)
+    push rbp
+    mov rbp, rsp    ; save base pointer
+
+    ; int count = [ rbp - 4 ]
+
+    sub rsp, 4      ; allocate local vars
+
+    call count_splits
+
+    mov rsp, rbp
+    pop rbp
+
+    ret
+
+    ; count = count_splits()
+    mov [rbp - 4], rax
+
+    pop rbp
+
+    ret