More-working syscall logic (parameters work!)

1 files changed, 9 insertions, 4 deletions

diff --git a/src/userspace/main.c b/src/userspace/main.c
index 22bb42a..5df961f 100644
--- a/src/userspace/main.c
+++ b/src/userspace/main.c
@@ -1,10 +1,15 @@
-#include <stddef.h>
-
-extern void syscall();
+void write(const char *str, int len)
+{
+    int ret;
+    asm volatile ("push %%ebx; movl %2,%%ebx; int $0x80; pop %%ebx" \
+                : "=a" (ret) \
+                : "0" (1), "b" ((int) (str)), "c"((int) (len)));
+}
 
 void user_main()
 {
-    syscall();
+    const char hello[] = "Switched to usermode!\n";
+    write(hello, sizeof(hello));
 
     while (1) {};
 }
\ No newline at end of file