From: Daniel Liu <mr.picklepinosaur@gmail.com>
Date: Sat, 19 Jun 2021 02:56:05 +0000 (-0400)
Subject: more work on reading file
X-Git-Url: https://git.danieliu.xyz/?p=sped.git;a=commitdiff_plain;h=f0c5604be9e918713786e0fdecd7efe1e3cea0ee

more work on reading file
---

diff --git a/makefile b/makefile
index 64a6613..d031d20 100644
--- a/makefile
+++ b/makefile
@@ -1,12 +1,14 @@
 CC=gcc
-CFLAGS=-m32 -no-pie -g
+CFLAGS=-m32 -no-pie
+ASM=nasm
+ASMFLAGS=-f elf32 -g -F dwarf
 
 .PHONY: clean
 
 make: sped
 
 sped.o: sped.asm
-	nasm -f elf32 $^ -o $@
+	$(ASM) $(ASMFLAGS) -g $^ -o $@
 
 sped: sped.o
 	$(CC) $(CFLAGS) $^ -o $@
diff --git a/sped.asm b/sped.asm
index a76e7de..859d386 100644
--- a/sped.asm
+++ b/sped.asm
@@ -1,3 +1,5 @@
+; sped - the stupidly pointless editor
+; written by pinosaur
 
 global main
 extern printf
@@ -17,27 +19,33 @@ section .data
     nofile_str db `no file provided\n`, 0x00
     argcount_str db `there are %d args\n`, 0x00
     wrongfile_str db `unable to open file, error code: %i\n`, 0x00
+    char_str db `read this char: %i\n`, 0x00
+    printfint_str db `int: %i\n`, 0x00
 
-; section .bss
+section .bss
+    read_buf resb 64
 
 section .text
 main:
+    %define _ARGC 8
+    %define _ARGV 12
+
     push ebp
     mov ebp, esp
 
     ; read command line args
-    mov ecx, [ebp+8]
+    mov ecx, [ebp+_ARGC]
     cmp ecx, 1
-    jg .main_existing
+    jg _main_existing
     
     ; display error msg if no file
     push nofile_str
     call printf
     mov eax, 1
-    jmp .main_exit
+    jmp _main_exit
 
-.main_existing:
-    mov ebx, DWORD [ebp+12]
+    _main_existing:
+    mov ebx, DWORD [ebp+_ARGV]
     add ebx, 4
     push DWORD [ebx]
     ; push readfile_str
@@ -46,13 +54,17 @@ main:
     call readFile
 
     mov eax, 0
-    jmp .main_exit
+    jmp _main_exit
+
+    _main_exit:
+    %undef _ARGC
+    %undef _ARGV
 
-.main_exit:
     mov esp, ebp
     pop ebp
     ret
 
+
 ; reads file line by line
 ; args: filename
 ; return:
@@ -68,29 +80,30 @@ readFile:
     ; allocate vars
     sub esp, 4
     mov DWORD [ebp-FILE_HANDLE], 0x00
-    
+
     ; open existing file
     mov eax, 5
     mov ebx, [ebp+_FILE_NAME]
     mov ecx, 0
-    mov edx, 0700
+    mov edx, 0777
     int 0x80
     mov [ebp-FILE_HANDLE], eax
 
     ; check if file was open successfully
     cmp eax, 0
-    jge .readFile_noerror
+    jge _readFile_noerror
     push eax
     push wrongfile_str
     call printf
-    jmp .readFile_exit
+    jmp _readFile_exit
 
-.readFile_noerror:
+    _readFile_noerror:
+    push DWORD [ebp-FILE_HANDLE]
+    call readLine 
 
-    jmp .readFile_exit
-
-.readFile_exit:
+    jmp _readFile_exit
 
+    _readFile_exit:
     ; close file
     mov eax, 6
     mov ebx, [ebp-FILE_HANDLE]
@@ -106,24 +119,61 @@ readFile:
 
 ; reads a line until newline character is reached
 ; args: file_handle
-; return: location to buffer
+; return:
+;   location to buffer
+;   contains eof
 readLine:
-    
     %define _FILE_HANDLE 8
+    %define CHAR_PTR 4
 
     push ebp
     mov ebp, esp
 
-.readLine_loop:
+    sub esp, 4
+    mov DWORD [ebp-CHAR_PTR], 0x00
+
+    _readLine_loop:
+    ; if buffer is full
+    cmp BYTE [ebp-CHAR_PTR], 64
+    jne _readLine_notfull
+    jmp _readLine_exit
 
+    _readLine_notfull:
     ; read a single character
     mov eax, 3
     mov ebx, [ebp+_FILE_HANDLE]
-    ; mov ecx, 
+    mov ecx, read_buf
+    add ecx, [ebp-CHAR_PTR]
     mov edx, 1
     int 0x80
 
-    jmp .readLine_loop
+    mov eax, 4
+    mov ebx, 1
+    mov ecx, read_buf
+    add ecx, [ebp-CHAR_PTR]
+    mov edx, 1
+    int 0x80
+
+    ; check for newline
+    mov eax, read_buf
+    add eax, [ebp-CHAR_PTR]
+    cmp DWORD [eax], 0x0a
+    je _readLine_exit
+    
+    ; check for eof
+    mov eax, read_buf
+    add eax, [ebp-CHAR_PTR]
+    cmp DWORD [eax], 0x05
+    je _readLine_exit
+
+    add DWORD [ebp-CHAR_PTR], 1
+
+    jmp _readLine_loop
+
+    _readLine_exit:
+
+    %undef _FILE_HANDLE
+    %undef CHAR_PTR
 
     mov esp, ebp
     pop ebp