Add basic thermal printer control

src/debug.c

@@ -0,0 +1,29 @@
+#include "debug.h"
+
+void Debug_Print(const char *message)
+{
+    uint32_t m[] = {2, (uint32_t)message, strlen(message)};
+    __asm__("mov r0, #0x05;"
+            "mov r1, %[m];"
+            "bkpt #0xAB"
+            :
+            : [m] "r" (m)
+            : "r0", "r1", "memory");
+}
+
+void Debug_PutChar(char c)
+{
+    uint32_t m[] = {2, (uint32_t)(&c), 1};
+    __asm__("mov r0, #0x05;"
+            "mov r1, %[m];"
+            "bkpt #0xAB"
+            :
+            : [m] "r" (m)
+            : "r0", "r1", "memory");
+//    __asm__("mov r0, #0x03;"
+//            "mov r1, %[msg];"
+//            "bkpt #0xAB"
+//            :
+//            : [msg] "r" (&c)
+//            : "r0", "r1");
+}