Add conio

Also removes print statements from the interrupt handler (except for the
button interrupt)

sw/conio.s

@@ -0,0 +1,60 @@
+.importzp sp, sreg
+
+.import _uart_txb_block
+.import _lastchar
+
+.export _cputc
+.export gotoxy
+.export _clrscr
+.export _cgetc
+
+.autoimport	on
+
+.code
+
+; void __fastcall__ cputc (char c);
+_cputc:
+        jsr _uart_txb_block
+        cmp #$0a
+        bne @1
+        lda #$0d
+        jsr _uart_txb_block
+@1:     rts
+
+; void __fastcall__ gotoxy (unsigned char x, unsigned char y);
+gotoxy:
+        phx
+        phy
+        tay                         ; Move y position to y
+        lda (sp)
+        tax                         ; Move x position to x
+        lda #$1b
+        jsr _uart_txb_block
+        lda #'['
+        jsr _uart_txb_block
+        tya
+        jsr _uart_txb_block
+        lda #';'
+        jsr _uart_txb_block
+        txa
+        jsr _uart_txb_block
+        lda #'H'
+        jsr _uart_txb_block
+        ply
+        plx
+        rts
+
+_clrscr:
+        phx
+        lda #$1b
+        jsr _uart_txb_block
+        lda #'c'
+        jsr _uart_txb_block
+        pla
+        rts
+
+_cgetc:
+@2:     lda _lastchar
+        beq @2
+        stz _lastchar
+        rts

sw/irq.c

@@ -1,30 +1,26 @@
 
 #include <stdint.h>
+#include <conio.h>
 
 #include "interrupt.h"
 #include "uart.h"
+#include "sevenseg.h"
+
+char lastchar;
 
-// This is defined in main.c
-void puts(const char* s);
 
 void handle_irq() {
     uint8_t status;
     char c;
 
-    puts("Interrupt Detected!\n");
-
     status = irq_get_status();
 
     if (status & BUTTON) {
-        puts("Button Interrupt!\n");
+        cputs("Button Interrupt!\n");
         irq_set_status(status & ~BUTTON);
     }
     if (status & UART) {
-        puts("UART Interrupt!\n");
-        c = uart_rxb();
-        puts("Received: ");
-        puts(&c);
-        puts("\n");
+        lastchar = uart_rxb();
         irq_set_status(status & ~UART);
     }
 }

sw/main.c

@@ -1,24 +1,20 @@
 #include <stdint.h>
+#include <conio.h>
 
 #include "sevenseg.h"
 #include "uart.h"
 
-void puts(const char* s)
-{
-    while (*s) {
-        uart_txb_block(*s);
-        if (*s == '\n')
-            uart_txb_block('\r');
-
-        s++;
-    }
-}
-
 int main() {
-    hex_enable(0x3f);
-    hex_set_24(0xabcdef);
+    char s[16];
+
+    clrscr();
+    cprintf("Hello, world!\n");
+
+    while (1) {
+        cscanf("%15s", s);
+        cprintf("Read string: %s\n", s);
+    }
+
 
-    puts("Hello, World!\n");
-    while(1);
     return 0;
 }