almost got the term emu working and shell

rocklibc/src/syscall.c

@@ -27,6 +27,10 @@ void exit(int status) {
     while(1);
 }
 
+int open(const char* path) {
+    return syscall1(SYS_OPEN, (uint32_t)path);
+}
+
 int write(int fd, const void* buf, size_t cnt) {
     return syscall3(SYS_WRITE, (uint32_t)fd, (uint32_t)buf, (uint32_t)cnt);
 }
@@ -35,10 +39,22 @@ int read(int fd, void* buf, size_t cnt) {
     return syscall3(SYS_READ, (uint32_t)fd, (uint32_t)buf, (uint32_t)cnt);
 }
 
+int close(int fd) {
+    return syscall1(SYS_CLOSE, fd);
+}
+
 int pty(int* slave) {
     return syscall1(SYS_PTY, (uint32_t)slave);
 }
 
 int fork() {
     return syscall1(SYS_FORK, 0);
+}
+
+int exec(const char* path) {
+    return syscall1(SYS_EXEC, (uint32_t)path);
+}
+
+int dup2(int src, int dst) {
+    return syscall3(SYS_DUP2, src, dst, 0);
 }