Serial Fix

Fixes a typo with getc_nb, removes the RTC tick code (since we know it
works now and it is clogging up the screen), read characters in a loop
instead of just once.

sw/kernel/devices/serial.s

@@ -9,7 +9,7 @@
 .export _serial_init
 .export _serial_handle_irq
 
-.export _serial_putc, _serial_puts, _serial_getc, _serial_get_nb
+.export _serial_putc, _serial_puts, _serial_getc, _serial_getc_nb
 
 .zeropage
 
@@ -39,8 +39,8 @@ UART_STATUS = UART + 1
 ; Get the character and store it.
 .proc _serial_handle_irq
         lda UART_RXB
-        sta last_char
         ora #$80        ; set msb
+        sta last_char
         jsr _send_eoi
         rti
 .endproc
@@ -58,7 +58,7 @@ L1:     lda last_char
 ; Serial Port Get Character Non-Blocking
 ; return last character, even if it has already been read.
 ; If the character is new, we still clear the new flag.
-.proc _serial_get_nb
+.proc _serial_getc_nb
         lda last_char
         bpl L1
         and #$7f

sw/kernel/kernel.c

@@ -8,7 +8,7 @@
 
 void handle_rtc_interrupt() {
     // cputs("In IRQ interrupt!\n");
-    cputc('A');
+    // cputc('A');
     send_eoi();
     asm volatile ("rti");
 }
@@ -40,12 +40,12 @@ int main() {
 
     serial_puts("Hello from serial!\n");
 
-    c = serial_getc();
-
-    serial_puts("Got a character!: ");
-    serial_putc(c);
-
-    while(1);
+    while(1) {
+        c = serial_getc();
+        serial_puts("Got a character!: ");
+        serial_putc(c);
+        serial_putc('\n');
+    }
 
     return 0;
 }