Subversion Repositories openrisc_2011-10-31

/* Stand-alone library for SPARClite

 *

 * Copyright (c) 1995 Cygnus Support

 *

 * The authors hereby grant permission to use, copy, modify, distribute,

 * and license this software and its documentation for any purpose, provided

 * that existing copyright notices are retained in all copies and that this

 * notice is included verbatim in any distributions. No written agreement,

 * license, or royalty fee is required for any of the authorized uses.

 * Modifications to this software may be copyrighted by their authors

 * and need not follow the licensing terms described here, provided that

 * the new terms are clearly indicated on the first page of each file where

 * they apply.

 */

#include "sparclite.h"

#include "asm.h"

/* LED blinking pattern can be changed by modifying __led_algorithm. */

enum ledtype

{

  led_marching,         /* marching pattern, only one led on at a time */

  led_random,           /* pseudo-random pattern */

  led_blinking,         /* all leds blink on and off */

  led_none              /* leds off all the time */

};

enum ledtype __led_algorithm = led_marching;

/* Pointer to hook for outbyte, set by stub's exception handler.  */

void (*__outbyte_hook) (int c);

#ifdef SL931

#define SDTR_BASE 0x200

#define SDTR_ASI 1

#define SDTR_SHIFT 0

#else

#define SDTR_BASE 0x10000000

#define SDTR_ASI 4

#define SDTR_SHIFT 16

#endif

#define get_uart_status(PORT) \

  (read_asi (SDTR_ASI, SDTR_BASE + 0x24 + (PORT) * 0x10) >> SDTR_SHIFT)

#define xmt_char(PORT, C) \

  write_asi (SDTR_ASI, SDTR_BASE + 0x20 + (PORT) * 0x10, (C) << SDTR_SHIFT)

#define rcv_char(PORT) \

  (read_asi (SDTR_ASI, SDTR_BASE + 0x20 + (PORT) * 0x10) >> SDTR_SHIFT)

void putDebugChar();

#if 0

void

set_uart (cmd)

     int cmd;

{

  write_asi (SDTR_ASI, SDTR_BASE + 0x24, cmd << SDTR_SHIFT);

}

void

set_timer_3 (val)

     int val;

{

  write_asi (SDTR_ASI, SDTR_BASE + 0x78, val << SDTR_SHIFT);

}

#endif

asm("

        .text

        .align 4

! Register window overflow handler.  Come here when save would move us

! into the invalid window.  This routine runs with traps disabled, and

! must be careful not to touch the condition codes, as PSR is never

! restored.

!

! We are called with %l0 = wim, %l1 = pc, %l2 = npc

        .globl " STRINGSYM(win_ovf) "

" STRINGSYM(win_ovf) ":

        mov     %g1, %l3                ! Save g1, we use it to hold the wim

        srl     %l0, 1, %g1             ! Rotate wim right

        sll     %l0, __WINSIZE-1, %l0

        or      %l0, %g1, %g1

        save    %g0, %g0, %g0           ! Slip into next window

        mov     %g1, %wim               ! Install the new wim

        std     %l0, [%sp + 0 * 4]      ! save L & I registers

        std     %l2, [%sp + 2 * 4]

        std     %l4, [%sp + 4 * 4]

        std     %l6, [%sp + 6 * 4]

        std     %i0, [%sp + 8 * 4]

        std     %i2, [%sp + 10 * 4]

        std     %i4, [%sp + 12 * 4]

        std     %i6, [%sp + 14 * 4]

        restore                         ! Go back to trap window.

        mov     %l3, %g1                ! Restore %g1

        jmpl    %l1,  %g0

        rett    %l2

! Register window underflow handler.  Come here when restore would move us

! into the invalid window.  This routine runs with traps disabled, and

! must be careful not to touch the condition codes, as PSR is never

! restored.

!

! We are called with %l0 = wim, %l1 = pc, %l2 = npc

        .globl " STRINGSYM(win_unf) "

" STRINGSYM(win_unf) ":

        sll     %l0, 1, %l3             ! Rotate wim left

        srl     %l0, __WINSIZE-1, %l0

        or      %l0, %l3, %l0

        mov     %l0, %wim               ! Install the new wim

        restore                         ! User's window

        restore                         ! His caller's window

        ldd     [%sp + 0 * 4], %l0      ! restore L & I registers

        ldd     [%sp + 2 * 4], %l2

        ldd     [%sp + 4 * 4], %l4

        ldd     [%sp + 6 * 4], %l6

        ldd     [%sp + 8 * 4], %i0

        ldd     [%sp + 10 * 4], %i2

        ldd     [%sp + 12 * 4], %i4

        ldd     [%sp + 14 * 4], %i6

        save    %g0, %g0, %g0           ! Back to trap window

        save    %g0, %g0, %g0

        jmpl    %l1,  %g0

        rett    %l2

! Read the TBR.

        .globl " STRINGSYM(rdtbr) "

" STRINGSYM(rdtbr) ":

        retl

        mov     %tbr, %o0

");

extern unsigned long rdtbr();

void

die(val)

     int val;

{

  static unsigned char *leds = (unsigned char *)0x02000003;

  *leds = val;

  while (1) ;

}

/* Each entry in the trap vector occupies four words. */

struct trap_entry

{

  unsigned sethi_filler:10;

  unsigned sethi_imm22:22;

  unsigned jmpl_filler:19;

  unsigned jmpl_simm13:13;

  unsigned long filler[2];

};

extern struct trap_entry fltr_proto;

asm ("

        .data

        .globl " STRINGSYM(fltr_proto) "

        .align 4

" STRINGSYM(fltr_proto) ":                      ! First level trap routine prototype

        sethi 0, %l0

        jmpl 0+%l0, %g0

        nop

        nop

        .text

        .align 4

");

/* Setup trap TT to go to ROUTINE.  If TT is between 0 and 255 inclusive, the

   normal trap vector will be used.  If TT is 256, then it's for the SPARClite

   DSU, and that always vectors off to 255 unrelocated.

*/

void

exceptionHandler (tt, routine)

     int tt;

     unsigned long routine;

{

  struct trap_entry *tb;        /* Trap vector base address */

  if (tt != 256)

    tb = (struct trap_entry *) (rdtbr() & ~0xfff);

  else

    {

      tt = 255;

      tb = (struct trap_entry *) 0;

    }

  tb[tt] = fltr_proto;

  tb[tt].sethi_imm22 = routine >> 10;

  tb[tt].jmpl_simm13 = routine & 0x3ff;

}

void

update_leds()

{

  static unsigned char *leds = (unsigned char *)0x02000003;

  static enum ledtype prev_algorithm = led_none;

  if (prev_algorithm != __led_algorithm)

    {

       *leds = 0xff;    /* turn the LEDs off */

       prev_algorithm = __led_algorithm;

    }

  switch (__led_algorithm)

    {

    case led_marching:

      {

        static unsigned char curled = 1;

        static unsigned char dir = 0;

        *leds = ~curled;

        if (dir)

          curled <<= 1;

        else

          curled >>= 1;

        if (curled == 0)

          {

            if (dir)

              curled = 0x80;

            else

              curled = 1;

            dir = ~dir;

          }

        break;

      }

    case led_random:

      {

        static unsigned int next = 0;

        *leds = next & 0xff;

        next = (next * 1103515245 + 12345) & 0x7fff;

        break;

      }

    case led_blinking:

      {

        static unsigned char next = 0;

        *leds = next;

        next = ~next;

        break;

      }

    default:

      break;

    }

}

 /* 1/5th of a second? */

#define LEDTIME (20000000 / 500)

unsigned long ledtime = LEDTIME;

int

inbyte()

{

        return (getDebugChar());

}

int

getDebugChar()

{

  unsigned long countdown = ledtime;

  update_leds();

  while (1)

    {

      if ((get_uart_status(0) & 2) != 0) break;

      if (countdown-- == 0)

        {

          countdown = ledtime;

          update_leds();

        }

    }

  return rcv_char(0);

}

/* Output one character to the serial port */

void

outbyte(c)

    int c;

{

  if (__outbyte_hook)

    __outbyte_hook (c);

  else

    putDebugChar(c);

}

void

putDebugChar(c)

     int c;

{

  update_leds();

  while ((get_uart_status(0) & 1) == 0) ;

  xmt_char(0, c);

}

#if 0

int

write(fd, data, length)

     int fd;

     unsigned char *data;

     int length;

{

  int olength = length;

  while (length--)

    putDebugChar(*data++);

  return olength;

}

int

read(fd, data, length)

     int fd;

     unsigned char *data;

     int length;

{

  int olength = length;

  int c;

  while (length--)

    *data++ = getDebugChar();

  return olength;

}

#endif

/* Set the baud rate for the serial port, returns 0 for success,

   -1 otherwise */

#if 0

int

set_baud_rate(baudrate)

     int baudrate;

{

  /* Convert baud rate to uart clock divider */

  switch (baudrate)

    {

    case 38400:

      baudrate = 16;

      break;

    case 19200:

      baudrate = 33;

      break;

    case 9600:

      baudrate = 65;

      break;

    default:

      return -1;

    }

  set_timer_3(baudrate);        /* Set it */

}

#endif