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xburst-tools/xbboot/target-echokernel/echo-kernel.c
2010-06-09 15:10:58 +08:00

65 lines
1.5 KiB
C

//
// Authors: Wolfgang Spraul <wolfgang@sharism.cc>
//
// 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 "../target-common/serial.h"
#include "../target-common/common.h"
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 + 0x1000;
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');
}
}
}