started implementing our first fool-shell.

1 files changed, 32 insertions, 28 deletions

diff --git a/userspace/syscalls.c b/userspace/syscalls.c
index 7b0f563..f4e77a1 100644
--- a/userspace/syscalls.c
+++ b/userspace/syscalls.c
@@ -45,23 +45,27 @@ int lseek(int file, int ptr, int dir)
 
 int read(int file, char *ptr, int len)
 {
-//    easywrite("syscall: read\n");
+	int ebx; // will hold return value;
+
+	asm("pusha");
+
+	// select syscall
+	asm("mov $62,%eax"); 
 
-    int i;
-    char buf[]="++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++..+++.>>.<-.<.+++.------.--------.>>+.>++.";
+	// pass params
+	asm("mov %0,%%edx"::"m"(file));
+	asm("mov %0,%%ecx"::"m"(ptr));
+	asm("mov %0,%%ebx"::"m"(len));
 
-    if(preread>=strlen(buf)){
-//	easywrite("syscall: read = EOF\n");
-	return 0; //EOF
-    }
+	// interrrupt
+	asm("int $0x80");
 
-    for(i=0;i<len;i++)
-    {
-	if(preread>=strlen(buf))return i;
-	ptr[i]=buf[preread++];
-    }
+	// get return value
+        asm("mov %%ebx, %0": "=b" (ebx));
+
+	asm("popa");
 
-    return len;
+	return ebx;
 }
 
 int open(const char *name, int flags, int mode)
@@ -73,28 +77,28 @@ int open(const char *name, int flags, int mode)
 
 int write(int file, char *ptr, int len) 
 {
-    int todo;
-    for (todo = 0; todo < len; todo++) 
-    {
-
-	char byte=(*ptr++);
-        int byt=byte;
 
 	int ebx; // will hold return value;
-	// system call 
+
 	asm("pusha");
-	asm("mov $61,%eax"); // select syscall)
+	
+	// select syscall
+	asm("mov $61,%eax"); 
 
-	asm("mov %0,%%edx"::"m"(byt));
-	//asm("mov $88,%edx");
+	// pass params
+	asm("mov %0,%%edx"::"m"(file));
+	asm("mov %0,%%ecx"::"m"(ptr));
+	asm("mov %0,%%ebx"::"m"(len));
+
+	// interrupt
+	asm("int $0x80");         
+
+	// get return value	
+	asm("mov %%ebx, %0": "=b" (ebx));
 
-	asm("int $0x80"); // actual syscall ! interrupt
-        asm("mov %%ebx, %0": "=b" (ebx));
 	asm("popa");
-	//
 	
-    }
-    return len;
+	return ebx;
 }