Split debug functions out into core/debug.c, so that they can be

automatically linked in on demand.

Corrected warnings in misc.c.  strtoul() really should be
  unsigned long strtoul ( const char *p, const char **endp, int base )
but such is not the ANSI standard.

src/core/debug.c

@@ -0,0 +1,87 @@
+#include <stdint.h>
+#include <io.h>
+#include <console.h>
+
+void pause ( void ) {
+	printf ( "\nPress a key" );
+	getchar();
+	printf ( "\r           \r" );
+}
+
+void more ( void ) {
+	printf ( "---more---" );
+	getchar();
+	printf ( "\r          \r" );
+}
+
+/* Produce a paged hex dump of the specified data and length */
+void hex_dump ( const char *data, const unsigned int len ) {
+	unsigned int index;
+	for ( index = 0; index < len; index++ ) {
+		if ( ( index % 16 ) == 0 ) {
+			printf ( "\n" );
+		}
+		if ( ( index % 368 ) == 352 ) {
+			more();
+		}
+		if ( ( index % 16 ) == 0 ) {
+			printf ( "%X [%X] : %hX :", data + index,
+				 virt_to_phys ( data + index ), index );
+		}
+		printf ( " %hhX", data[index] );
+	}
+	printf ( "\n" );
+}
+
+#define GUARD_SYMBOL ( ( 'M' << 24 ) | ( 'I' << 16 ) | ( 'N' << 8 ) | 'E' )
+/* Fill a region with guard markers.  We use a 4-byte pattern to make
+ * it less likely that check_region will find spurious 1-byte regions
+ * of non-corruption.
+ */
+void guard_region ( void *region, size_t len ) {
+	uint32_t offset = 0;
+
+	len &= ~0x03;
+	for ( offset = 0; offset < len ; offset += 4 ) {
+		*((uint32_t *)(region + offset)) = GUARD_SYMBOL;
+	}
+}
+
+/* Check a region that has been guarded with guard_region() for
+ * corruption.
+ */
+int check_region ( void *region, size_t len ) {
+	uint8_t corrupted = 0;
+	uint8_t in_corruption = 0;
+	uint32_t offset = 0;
+	uint32_t test = 0;
+
+	len &= ~0x03;
+	for ( offset = 0; offset < len ; offset += 4 ) {
+		test = *((uint32_t *)(region + offset)) = GUARD_SYMBOL;
+		if ( ( in_corruption == 0 ) &&
+		     ( test != GUARD_SYMBOL ) ) {
+			/* Start of corruption */
+			if ( corrupted == 0 ) {
+				corrupted = 1;
+				printf ( "Region %#x-%#x (physical %#x-%#x) "
+					 "corrupted\n",
+					 region, region + len,
+					 virt_to_phys ( region ),
+					 virt_to_phys ( region + len ) );
+			}
+			in_corruption = 1;
+			printf ( "--- offset %#x ", offset );
+		} else if ( ( in_corruption != 0 ) &&
+			    ( test == GUARD_SYMBOL ) ) {
+			/* End of corruption */
+			in_corruption = 0;
+			printf ( "to offset %#x", offset );
+		}
+
+	}
+	if ( in_corruption != 0 ) {
+		printf ( "to offset %#x (end of region)\n", len-1 );
+	}
+	return corrupted;
+}