implement getchar() and putchar() in terms of supervisor call

1 files changed, 11 insertions, 16 deletions

diff --git a/PL0_test.c b/PL0_test.c
index 2e008a2..f476eb7 100644
--- a/PL0_test.c
+++ b/PL0_test.c
@@ -1,34 +1,29 @@
-#include "uart.h"
-#include "psr.h"
+#include "PL0_utils.h"
 
 // entry point - must remain the only function in the file!
 void PL0_main(void)
 {
-  // If all went correct, Success! gets printed
-  uart_puts("Success!\n\r");
-
-  uart_puts("calling supervisor\n\r");
-  
-  asm volatile("svc #0");
-
-  uart_puts("back from supervisor call\n\r");
+  // If loading program to userspace and handling of svc are
+  // implemented correctly, this shall get printed
+  puts("Hello userspace!");
   
-  // if we're indeed in PL0, we should crash now, when trying to access
-  // memory we're not allowed to
+  // if we're indeed in PL0, we should trigger the abort handler now,
+  // when trying to access memory we're not allowed to
+  puts("Attempting to meddle with kernel memory from userspace :d");
   char first_kernel_byte[2];
 
-  first_kernel_byte[0] = *(char*) ((uint32_t) 0x0);
+  first_kernel_byte[0] = *(char*) 0x0;
   first_kernel_byte[1] = '\0';
 
   uart_puts(first_kernel_byte);
     
   while (1)
     {
-      char c = uart_getc();
+      char c = getchar();
 
-      uart_putc(c);
+      putchar(c);
       
       if (c == '\r')
-	uart_putc('\n');
+	putchar('\n');
     }
 }