Created xbboot.

xbboot/target-echokernel/echo-kernel.c

@@ -0,0 +1,67 @@
+//
+// Authors: Wolfgang Spraul <wolfgang@qi-hardware.com>
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version
+// 3 of the License, or (at your option) any later version.
+//
+
+#include <inttypes.h>
+#include "../target-common/jz4740.h"
+#include "../target-common/serial.h"
+
+void c_main();
+
+void pre_main(void)
+{
+	volatile unsigned int start_addr, got_start, got_end, addr, offset;
+
+	/* get absolute start address  */
+	__asm__ __volatile__(			
+		"move %0, $20\n\t"
+		: "=r"(start_addr)
+		: 
+		);			
+
+	/* get related GOT address  */
+	__asm__ __volatile__(			
+		"la $4, _GLOBAL_OFFSET_TABLE_\n\t"
+		"move %0, $4\n\t"
+		"la $5, _got_end\n\t"
+		"move %1, $5\n\t"
+		: "=r"(got_start),"=r"(got_end)
+		: 
+		);			
+
+	/* calculate offset and correct GOT*/
+	offset = start_addr - 0x80000000;	
+ 	got_start += offset;
+	got_end  += offset;
+
+	for ( addr = got_start + 8; addr < got_end; addr += 4 )
+		*((volatile unsigned int *)(addr)) += offset; // add offset to correct all GOT
+
+//	fw_args = (struct fw_args *)(start_addr + 0x8);       //get the fw args from memory
+	UART_BASE = 0xB0030000;
+	serial_puts("Start address is:");
+	serial_put_hex(start_addr);
+	serial_puts("Address offset is:");
+	serial_put_hex(start_addr - 0x80000000);
+	serial_puts("GOT corrected to:");
+	serial_put_hex(got_start);
+	c_main();
+}
+
+void c_main()
+{
+	// start infinite 'echo' kernel
+	while (1) {
+		if (serial_tstc()) {
+			int c = serial_getc();
+			serial_putc(c);
+			if (c == '\r')
+				serial_putc('\n');
+		}
+	}
+}