Subversion Repositories openrisc_2011-10-31

/*

 * Copyright (c) 1996 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 <string.h>

#include <signal.h>

#include "debug.h"

#include "asm.h"

#include "slite.h"

extern unsigned long rdtbr();

extern struct trap_entry fltr_proto;

extern void trap_low();

exception_t default_trap_hook = trap_low;

void target_reset();

void flush_i_cache();

char *target_read_registers(unsigned long *);

char *target_write_registers(unsigned long *);

char *target_dump_state(unsigned long *);

#define NUMREGS 72

/* Number of bytes of registers.  */

#define NUMREGBYTES (NUMREGS * 4)

enum regnames {G0, G1, G2, G3, G4, G5, G6, G7,

                 O0, O1, O2, O3, O4, O5, SP, O7,

                 L0, L1, L2, L3, L4, L5, L6, L7,

                 I0, I1, I2, I3, I4, I5, FP, I7,

                 F0, F1, F2, F3, F4, F5, F6, F7,

                 F8, F9, F10, F11, F12, F13, F14, F15,

                 F16, F17, F18, F19, F20, F21, F22, F23,

                 F24, F25, F26, F27, F28, F29, F30, F31,

                 Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR };

/*

 * Each entry in the trap vector occupies four words, typically a jump

 * to the processing routine.

 */

struct trap_entry {

  unsigned sethi_filler:10;

  unsigned sethi_imm22:22;

  unsigned jmpl_filler:19;

  unsigned jmpl_simm13:13;

  unsigned long filler[2];

};

/*

 * This table contains the mapping between SPARC hardware trap types, and

 * signals, which are primarily what GDB understands.  It also indicates

 * which hardware traps we need to commandeer when initializing the stub.

 */

struct trap_info hard_trap_info[] = {

  {1, SIGSEGV},                 /* instruction access error */

  {2, SIGILL},                  /* privileged instruction */

  {3, SIGILL},                  /* illegal instruction */

  {4, SIGEMT},                  /* fp disabled */

  {36, SIGEMT},                 /* cp disabled */

  {7, SIGBUS},                  /* mem address not aligned */

  {9, SIGSEGV},                 /* data access exception */

  {10, SIGEMT},                 /* tag overflow */

  {128+1, SIGTRAP},             /* ta 1 - normal breakpoint instruction */

  {0, 0}                  /* Must be last */

};

extern struct trap_entry fltr_proto;

void

exception_handler (int tt, unsigned long routine)

{

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

  DEBUG (1, "Entering exception_handler()");

  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;

  DEBUG (1, "Leaving exception_handler()");

}

/*

 * This is so we can trap a memory fault when reading or writing

 * directly to memory.

 */

void

set_mem_fault_trap(enable)

     int enable;

{

  extern void fltr_set_mem_err();

  DEBUG (1, "Entering set_mem_fault_trap()");

  mem_err = 0;

  if (enable)

    exception_handler(9, (unsigned long)fltr_set_mem_err);

  else

    exception_handler(9, (unsigned long)trap_low);

  DEBUG (1, "Leaving set_mem_fault_trap()");

}

/*

 * This function does all command procesing for interfacing to gdb.  It

 * returns 1 if you should skip the instruction at the trap address, 0

 * otherwise.

 */

extern void breakinst();

void

handle_exception (registers)

     unsigned long *registers;

{

  int sigval;

  /* First, we must force all of the windows to be spilled out */

  DEBUG (1, "Entering handle_exception()");

/*  asm("mov %g0, %wim ; nop; nop; nop"); */

  asm(" save %sp, -64, %sp      \n\

        save %sp, -64, %sp      \n\

        save %sp, -64, %sp      \n\

        save %sp, -64, %sp      \n\

        save %sp, -64, %sp      \n\

        save %sp, -64, %sp      \n\

        save %sp, -64, %sp      \n\

        save %sp, -64, %sp      \n\

        restore                 \n\

        restore                 \n\

        restore                 \n\

        restore                 \n\

        restore                 \n\

        restore                 \n\

        restore                 \n\

        restore                 \n\

");

  if (registers[PC] == (unsigned long)breakinst) {

    registers[PC] = registers[NPC];

    registers[NPC] += 4;

  }

  /* get the last know signal number from the trap register */

  sigval = computeSignal((registers[TBR] >> 4) & 0xff);

  /* call the main command processing loop for gdb */

  gdb_event_loop (sigval, registers);

}

/*

 * This function will generate a breakpoint exception.  It is used at the

 * beginning of a program to sync up with a debugger and can be used

 * otherwise as a quick means to stop program execution and "break" into

 * the debugger.

 */

void

breakpoint()

{

  DEBUG (1, "Entering breakpoint()");

  if (!initialized)

    return;

  asm(" .globl " STRINGSYM(breakinst) "         \n\

        " STRINGSYM(breakinst) ": ta 128+1      \n\

        nop                                     \n\

        nop                                     \n\

      ");

}

/*

 * This is just a test vector for debugging excpetions.

 */

void

bad_trap(tt)

int tt;

{

  print ("Got a bad trap #");

  outbyte (tt);

  outbyte ('\n');

  asm("ta 0             \n\

        nop             \n\

        nop             \n\

      ");

}

/*

 * This is just a test vector for debugging excpetions.

 */

void

soft_trap(tt)

int tt;

{

  print ("Got a soft trap #");

  outbyte (tt);

  outbyte ('\n');

  asm("ta 0             \n\

        nop             \n\

        nop             \n\

      ");

}

/*

 * Flush the instruction cache.  We need to do this for the debugger stub so

 * that breakpoints, et. al. become visible to the instruction stream after

 * storing them in memory.

 *

 * For the sparclite, we need to do something here, but for a standard

 * sparc (which SIS simulates), we don't.

 */

void

flush_i_cache ()

{

}

/*

 * This will reset the processor, so we never return from here.

 */

void

target_reset()

{

  asm ("call 0          \n\

        nop ");

}

/*

 * g - read registers.

 *      no params.

 *      returns a vector of words, size is NUM_REGS.

 */

char *

target_read_registers(unsigned long *registers)

{

  char *ptr;

  unsigned long *sp;

  DEBUG (1, "In target_read_registers()");

  ptr = packet_out_buf;

  ptr = mem2hex((char *)registers, ptr, 16 * 4, 0); /* G & O regs */

  ptr = mem2hex((unsigned char *)(sp + 0), ptr, 16 * 4, 0); /* L & I regs */

  memset(ptr, '0', 32 * 8); /* Floating point */

  mem2hex((char *)&registers[Y],

          ptr + 32 * 4 * 2,

          8 * 4,

          0);            /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */

  return (ptr);

}

/*

 * G - write registers.

 *      param is a vector of words, size is NUM_REGS.

 *      returns an OK or an error number.

 */

char *

target_write_registers(unsigned long *registers)

{

  unsigned char *ptr;

  unsigned long *sp;

  unsigned long *newsp, psr;

  DEBUG (1, "In target_write_registers()");

  psr = registers[PSR];

  ptr = &packet_in_buf[1];

  hex2mem(ptr, (char *)registers, 16 * 4, 0); /* G & O regs */

  hex2mem(ptr + 16 * 4 * 2, (unsigned char *)(sp + 0), 16 * 4, 0); /* L & I regs */

  hex2mem(ptr + 64 * 4 * 2, (char *)&registers[Y],

          8 * 4, 0);     /* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */

  /*

   * see if the stack pointer has moved.  If so, then copy the saved

   * locals and ins to the new location.  This keeps the window

   * overflow and underflow routines happy.

   */

  newsp = (unsigned long *)registers[SP];

  if (sp != newsp)

    sp = memcpy(newsp, sp, 16 * 4);

  /* Don't allow CWP to be modified. */

  if (psr != registers[PSR])

    registers[PSR] = (psr & 0x1f) | (registers[PSR] & ~0x1f);

  return (ptr);

}

char *

target_dump_state(unsigned long *registers)

{

  int tt;                       /* Trap type */

  int sigval;

  char *ptr;

  unsigned long *sp;

  DEBUG (1, "In target_dump_state()");

  sp = (unsigned long *)registers[SP];

  tt = (registers[TBR] >> 4) & 0xff;

  /* reply to host that an exception has occurred */

  sigval = computeSignal(tt);

  ptr = packet_out_buf;

  *ptr++ = 'T';

  *ptr++ = hexchars[sigval >> 4];

  *ptr++ = hexchars[sigval & 0xf];

  *ptr++ = hexchars[PC >> 4];

  *ptr++ = hexchars[PC & 0xf];

  *ptr++ = ':';

  ptr = mem2hex((unsigned char *)&registers[PC], ptr, 4, 0);

  *ptr++ = ';';

  *ptr++ = hexchars[FP >> 4];

  *ptr++ = hexchars[FP & 0xf];

  *ptr++ = ':';

  ptr = mem2hex((unsigned char *)(sp + 8 + 6), ptr, 4, 0); /* FP */

  *ptr++ = ';';

  *ptr++ = hexchars[SP >> 4];

  *ptr++ = hexchars[SP & 0xf];

  *ptr++ = ':';

  ptr = mem2hex((unsigned char *)&sp, ptr, 4, 0);

  *ptr++ = ';';

  *ptr++ = hexchars[NPC >> 4];

  return (packet_out_buf);

}

void

write_pc(unsigned long *registers, unsigned long addr)

{

  DEBUG (1, "In write_pc");

  registers[PC] = addr;

  registers[NPC] = addr + 4;

}