Add sys_hello and testbin/hellotest

`sys_hello` is a new syscall that just prints some text in the terminal.

`testbin/hellotest` is a userland binary that just calls `sys_hello`

kern/arch/mips/syscall/syscall.c

@@ -104,22 +104,15 @@ void syscall(struct trapframe *tf) {
   case SYS___time:
     err = sys___time((userptr_t)tf->tf_a0, (userptr_t)tf->tf_a1);
     break;
+  case SYS_hello:
+    err = sys_hello();
+    break;
 
   case SYS__exit:
     err = 0;
     thread_exit();
     break;
 
-  case SYS_printchar:
-    err = sys_printchar((char)tf->tf_a0);
-    break;
-
-  case SYS_add_three_integers:
-    err = sys_add_three_integers((int)tf->tf_a0, (int)tf->tf_a1, (int)tf->tf_a2,
-                                 &retval);
-    kprintf("%d\n", retval);
-    break;
-
     /* Add stuff here */
 
   default:

kern/conf/conf.kern

@@ -379,8 +379,7 @@ file      vfs/devnull.c
 file      syscall/loadelf.c
 file      syscall/runprogram.c
 file      syscall/time_syscalls.c
-file      syscall/printchar.c
+file      syscall/hello.c
-file      syscall/add_three_integers.c
 
 #
 # Startup and initialization

kern/include/kern/syscall.h

@@ -94,8 +94,7 @@
 // #define SYS_getpriority 38
 // #define SYS_setpriority 39
 //                               (process groups, sessions, and job control)
-#define SYS_printchar 41
+#define SYS_hello 41
-#define SYS_add_three_integers 42
 // #define SYS_getpgid    40
 // #define SYS_setpgid    41
 // #define SYS_getsid     42

kern/include/syscall.h

@@ -57,8 +57,6 @@ __DEAD void enter_new_process(int argc, userptr_t argv, userptr_t env,
 int sys_reboot(int code);
 int sys___time(userptr_t user_seconds, userptr_t user_nanoseconds);
 
-int sys_printchar(char c);
+int sys_hello(void);
-
-int sys_add_three_integers(int a, int b, int c, int *ret);
 
 #endif /* _SYSCALL_H_ */

kern/syscall/add_three_integers.c

@@ -1,8 +0,0 @@
-#include <types.h>
-#include <lib.h>
-#include <syscall.h>
-
-int sys_add_three_integers(int a, int b, int c, int *ret) {
-  *ret = a + b + c;
-  return 0;
-}

kern/syscall/hello.c

@@ -1,7 +1,7 @@
 #include <types.h>
 #include <lib.h>
 #include <syscall.h>
-int sys_printchar(char c) {
+int sys_hello(void) {
-  kprintf("%c", c);
+  kprintf("Hello CSE4001!\n");
   return 0;
 }

userland/include/unistd.h

@@ -156,7 +156,6 @@ int execvp(const char *prog, char *const *args); /* calls execv */
 char *getcwd(char *buf, size_t buflen);          /* calls __getcwd */
 time_t time(time_t *seconds);                    /* calls __time */
 
-int printchar(char c);
+int hello(void);
-int add_three_integers(int a, int b, int c);
 
 #endif /* _UNISTD_H_ */

userland/testbin/Makefile

@@ -5,10 +5,10 @@
 TOP=../..
 .include "$(TOP)/mk/os161.config.mk"
 
-SUBDIRS=add add_three_integers argtest badcall bigexec bigfile bigfork bigseek bloat conman \
+SUBDIRS=add argtest badcall bigexec bigfile bigfork bigseek bloat conman \
 	crash ctest dirconc dirseek dirtest f_test factorial farm faulter \
-	filetest forkbomb forktest frack hash hog huge \
+	filetest forkbomb forktest frack hash hellotest hog huge \
-	malloctest matmult multiexec palin parallelvm poisondisk printchartest psort \
+	malloctest matmult multiexec palin parallelvm poisondisk psort \
 	randcall redirect rmdirtest rmtest \
 	sbrktest schedpong sort sparsefile tail tictac triplehuge \
 	triplemat triplesort usemtest zero

userland/testbin/add_three_integers/Makefile

@@ -1,10 +0,0 @@
-# Makefile for add_three_integers
-
-TOP=../../..
-.include "$(TOP)/mk/os161.config.mk"
-
-PROG=add_three_integers
-SRCS=add_three_integers.c
-BINDIR=/testbin
-
-.include "$(TOP)/mk/os161.prog.mk"

userland/testbin/add_three_integers/add_three_integers.c

@@ -1,10 +0,0 @@
-#include <unistd.h>
-
-extern int add_three_integers(int a, int b, int c);
-
-int main() {
-  add_three_integers(3, 5, 2);  // should output 10
-  add_three_integers(-5, 3, 1); // should output -1
-
-  return 0;
-}

userland/testbin/hellotest/Makefile

@@ -1,10 +1,10 @@
-# Makefile for printchartest
+# Makefile for hello
 
 TOP=../../..
 .include "$(TOP)/mk/os161.config.mk"
 
-PROG=printchartest
+PROG=hellotest
-SRCS=printchartest.c
+SRCS=hello.c
 BINDIR=/testbin
 
 .include "$(TOP)/mk/os161.prog.mk"

userland/testbin/hellotest/hello.c

@@ -0,0 +1,8 @@
+#include <unistd.h>
+
+extern int hello(void);
+
+int main() {
+  hello();
+  return 0;
+}

userland/testbin/printchartest/printchartest.c

@@ -1,17 +0,0 @@
-#include <unistd.h>
-
-extern int printchar(char c);
-
-int main() {
-
-  printchar('C');
-  printchar('S');
-  printchar('E');
-  printchar('4');
-  printchar('0');
-  printchar('0');
-  printchar('1');
-  printchar('\n');
-
-  return 0;
-}