From: Daniel Liu <mr.picklepinosaur@gmail.com>
Date: Fri, 18 Jun 2021 18:54:04 +0000 (-0400)
Subject: reading command line arg
X-Git-Url: https://git.danieliu.xyz/?p=sped.git;a=commitdiff_plain;h=17adbf435e9341831aa580404d18d8caa7448ce2

reading command line arg
---

diff --git a/makefile b/makefile
index d83be28..64a6613 100644
--- a/makefile
+++ b/makefile
@@ -1,3 +1,5 @@
+CC=gcc
+CFLAGS=-m32 -no-pie -g
 
 .PHONY: clean
 
@@ -7,7 +9,7 @@ sped.o: sped.asm
 	nasm -f elf32 $^ -o $@
 
 sped: sped.o
-	ld -m elf_i386 $^ -o $@
+	$(CC) $(CFLAGS) $^ -o $@
 
 clean:
 	rm sped *.o
diff --git a/sped.asm b/sped.asm
index 6230c85..eda67b3 100644
--- a/sped.asm
+++ b/sped.asm
@@ -1,4 +1,8 @@
 
+global main
+extern printf
+
+; macros
 %macro write_str 2
     mov eax, 4
     mov ebx, 1
@@ -8,14 +12,41 @@
 %endmacro
 
 section .data
-    msg db "SPED - the stupidly pointless editor", 0x0a
-    len equ $ - msg
+    banner_str db `SPED - the stupidly pointless editor\n`, 0x00
+    readfile_str db `reading file %s\n`, 0x00
+    nofile_str db `no file provided\n`, 0x00
+    argcount_str db `there are %d args\n`, 0x00
 
 section .text
-global _start
-_start:
-    write_str msg, len
+main:
+    push ebp
+    mov ebp, esp
+
+    ; read command line args
+    mov ecx, [ebp+8]
 
+    cmp ecx, 1
+    jg .readFile
+    
+    ; display error msg if no file
+    push nofile_str
+    call printf
     mov eax, 1
-    mov ebx, 42
-    int 0x80
+    jmp .exit
+
+.readFile:
+
+    mov ebx, DWORD [ebp+12]
+    add ebx, 4
+    push DWORD [ebx]
+    push readfile_str
+    call printf
+
+    mov eax, 0
+    jmp .exit
+
+.exit:
+    mov esp, ebp
+    pop ebp
+    ret
+