From 7a7ed6ae81978b84911dab0b902e77ebb7e9b735 Mon Sep 17 00:00:00 2001
From: Daniel Liu <mr.picklepinosaur@gmail.com>
Date: Sat, 19 Jun 2021 19:43:47 -0400
Subject: [PATCH] writing to file done

---
 README.md     |  2 +-
 fileutils.S   |  1 +
 fileutils.asm | 77 +++++++++++++++++++++++++++++++++++++++++++++++++--
 sped.asm      | 19 ++++++++++++-
 4 files changed, 95 insertions(+), 4 deletions(-)

diff --git a/README.md b/README.md
index 0664806..4ea05df 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,7 @@ This is my own stupid and pointless attempt at writing such line editor.
 
 #### Build from source
 
-With `gcc` and `nasm` installed, you can simply run
+with `gcc` and `nasm` installed, you can simply run
 ```
 make
 ```
diff --git a/fileutils.S b/fileutils.S
index 7ce6be3..5a77864 100644
--- a/fileutils.S
+++ b/fileutils.S
@@ -4,5 +4,6 @@
 
 extern readFile
 extern readLine
+extern writeFile
 
 %endif
diff --git a/fileutils.asm b/fileutils.asm
index 8596ff3..b9b41e7 100644
--- a/fileutils.asm
+++ b/fileutils.asm
@@ -1,12 +1,16 @@
 
+; %include "utils.S"
+
 extern printf
 extern malloc
 extern realloc
 extern free
 extern memset
+extern strlen
 
 global readFile
 global readLine
+global writeFile
 
 section .data
     wrongfile_str db `unable to open file, error code: %i\n`, 0x00
@@ -202,6 +206,75 @@ readLine:
     ret
 
 ; writes contents of string array into file
-; arg: filename, string array
-; writeFile:
+; arg: filename, string array, number of lines
+writeFile:
+
+    %define _FILE_NAME    16
+    %define _STR_ARR      12
+    %define _STR_ARR_LEN  8
+    %define FILE_HANDLE   4
+    %define LINES_WRITTEN 8
+
+    push ebp
+    mov ebp, esp
+
+    ; allocate vars
+    sub esp, 8
+    mov DWORD [ebp-FILE_HANDLE], 0x00
+    mov DWORD [ebp-LINES_WRITTEN], 0x00
+
+    ; open existing file
+    mov eax, 5
+    mov ebx, [ebp+_FILE_NAME]
+    mov ecx, 2
+    mov edx, 0777
+    int 0x80
+    mov [ebp-FILE_HANDLE], eax
+
+    ; check if file was open successfully
+    cmp eax, 0
+    jge _writeFile_loop
+    push eax
+    push wrongfile_str
+    call printf
+    jmp _writeFile_exit
+    
+    _writeFile_loop:
+
+    ; check if we are done writing
+    mov eax, [ebp+_STR_ARR_LEN]
+    cmp eax, [ebp-LINES_WRITTEN]
+    je _writeFile_exit
+
+    ; get length of string to write
+    str_offset [ebp+_STR_ARR], [ebp-LINES_WRITTEN]
+    mov esi, eax
+    push DWORD [esi]
+    call strlen
+
+    mov edx, eax
+    mov eax, 4
+    mov ebx, [ebp-FILE_HANDLE]    
+    mov ecx, [esi]
+    int 0x80
+
+    add DWORD [ebp-LINES_WRITTEN], 1
+
+    jmp _writeFile_loop
+
+    _writeFile_exit:
+
+    ; close file
+    mov eax, 6
+    mov ebx, [ebp-FILE_HANDLE]
+    int 0x80
+    
+    %undef _FILE_NAME
+    %undef _STR_ARR
+    %undef _STR_ARR_LEN
+    %undef FILE_HANDLE
+    
+    mov esp, ebp
+    pop ebp
+    ret
 
diff --git a/sped.asm b/sped.asm
index d7dcb8d..213f3ea 100644
--- a/sped.asm
+++ b/sped.asm
@@ -33,6 +33,7 @@ section .data
 section .bss
     buffer resb 4
     buffer_lines resb 4
+    buffer_filename resb 4
     cur_line resb 4
 
 section .text
@@ -57,7 +58,10 @@ main:
     _main_existing:
     mov ebx, DWORD [ebp+_ARGV]
     add ebx, 4 ; first user arg is filename
-    push DWORD [ebx]
+    mov ebx, [ebx]
+    mov [buffer_filename], ebx
+
+    push DWORD [buffer_filename]
     call readFile
 
     mov [buffer], eax
@@ -235,6 +239,19 @@ repl:
     jmp _repl_continue
     _repl_cmd_change_end:
 
+    ; w writes file =-=-=-=-=-=-=-=-=-=-=-=-=
+    mov eax, DWORD [ebp-CMDSTR]
+    cmp BYTE [eax], 'w'
+    jne _repl_cmd_write_end
+
+    push DWORD [buffer_filename]
+    push DWORD [buffer]
+    push DWORD [buffer_lines]
+    call writeFile
+
+    jmp _repl_continue
+    _repl_cmd_write_end:
+
 
     jmp _repl_invalid_cmd
 
-- 
2.20.1