364 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			C
		
	
	
	
			
		
		
	
	
			364 lines
		
	
	
		
			8.4 KiB
		
	
	
	
		
			C
		
	
	
	
/*
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 * Copyright (c) 1996 Cygnus Support
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 *
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 * The authors hereby grant permission to use, copy, modify, distribute,
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 * and license this software and its documentation for any purpose, provided
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 * that existing copyright notices are retained in all copies and that this
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 * notice is included verbatim in any distributions. No written agreement,
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 * license, or royalty fee is required for any of the authorized uses.
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 * Modifications to this software may be copyrighted by their authors
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 * and need not follow the licensing terms described here, provided that
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 * the new terms are clearly indicated on the first page of each file where
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 * they apply.
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 */
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#include <string.h>
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#include <signal.h>
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#include "debug.h"
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#include "asm.h"
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#include "slite.h"
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extern unsigned long rdtbr();
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extern struct trap_entry fltr_proto;
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extern void trap_low();
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exception_t default_trap_hook = trap_low;
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void target_reset();
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void flush_i_cache();
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char *target_read_registers(unsigned long *);
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char *target_write_registers(unsigned long *);
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char *target_dump_state(unsigned long *);
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#define NUMREGS 72
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/* Number of bytes of registers.  */
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#define NUMREGBYTES (NUMREGS * 4)
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enum regnames {G0, G1, G2, G3, G4, G5, G6, G7,
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		 O0, O1, O2, O3, O4, O5, SP, O7,
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		 L0, L1, L2, L3, L4, L5, L6, L7,
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		 I0, I1, I2, I3, I4, I5, FP, I7,
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		 F0, F1, F2, F3, F4, F5, F6, F7,
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		 F8, F9, F10, F11, F12, F13, F14, F15,
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		 F16, F17, F18, F19, F20, F21, F22, F23,
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		 F24, F25, F26, F27, F28, F29, F30, F31,
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		 Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR };
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/*
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 * Each entry in the trap vector occupies four words, typically a jump
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 * to the processing routine.
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 */
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struct trap_entry {
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  unsigned sethi_filler:10;
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  unsigned sethi_imm22:22;
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  unsigned jmpl_filler:19;
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  unsigned jmpl_simm13:13;
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  unsigned long filler[2];
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};
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/*
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 * This table contains the mapping between SPARC hardware trap types, and
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 * signals, which are primarily what GDB understands.  It also indicates
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 * which hardware traps we need to commandeer when initializing the stub.
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 */
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struct trap_info hard_trap_info[] = {
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  {1, SIGSEGV},			/* instruction access error */
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  {2, SIGILL},			/* privileged instruction */
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  {3, SIGILL},			/* illegal instruction */
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  {4, SIGEMT},			/* fp disabled */
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  {36, SIGEMT},			/* cp disabled */
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  {7, SIGBUS},			/* mem address not aligned */
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  {9, SIGSEGV},			/* data access exception */
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  {10, SIGEMT},			/* tag overflow */
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  {128+1, SIGTRAP},		/* ta 1 - normal breakpoint instruction */
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  {0, 0}			/* Must be last */
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};
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extern struct trap_entry fltr_proto;
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void
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exception_handler (int tt, unsigned long routine)
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{
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  struct trap_entry *tb;        /* Trap vector base address */
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  DEBUG (1, "Entering exception_handler()");
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  if (tt != 256) {
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    tb = (struct trap_entry *) (rdtbr() & ~0xfff);
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  } else {
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    tt = 255;
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    tb = (struct trap_entry *) 0;
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  }
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  tb[tt] = fltr_proto;
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  tb[tt].sethi_imm22 = routine >> 10;
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  tb[tt].jmpl_simm13 = routine & 0x3ff;
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  DEBUG (1, "Leaving exception_handler()");
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}
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/*
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 * This is so we can trap a memory fault when reading or writing
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 * directly to memory.
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 */
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void
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set_mem_fault_trap(enable)
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     int enable;
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{
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  extern void fltr_set_mem_err();
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  DEBUG (1, "Entering set_mem_fault_trap()");
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  mem_err = 0;
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  if (enable)
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    exception_handler(9, (unsigned long)fltr_set_mem_err);
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  else
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    exception_handler(9, (unsigned long)trap_low);
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  DEBUG (1, "Leaving set_mem_fault_trap()");
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}
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/*
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 * This function does all command procesing for interfacing to gdb.  It
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 * returns 1 if you should skip the instruction at the trap address, 0
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 * otherwise.
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 */
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extern void breakinst();
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void
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handle_exception (registers)
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     unsigned long *registers;
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{
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  int sigval;
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  /* First, we must force all of the windows to be spilled out */
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  DEBUG (1, "Entering handle_exception()");
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/*  asm("mov %g0, %wim ; nop; nop; nop"); */
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  asm("	save %sp, -64, %sp	\n\
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	save %sp, -64, %sp	\n\
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	save %sp, -64, %sp	\n\
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	save %sp, -64, %sp	\n\
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	save %sp, -64, %sp	\n\
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	save %sp, -64, %sp	\n\
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	save %sp, -64, %sp	\n\
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	save %sp, -64, %sp	\n\
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	restore			\n\
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	restore			\n\
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	restore			\n\
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	restore			\n\
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	restore			\n\
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	restore			\n\
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	restore			\n\
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	restore			\n\
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");
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  if (registers[PC] == (unsigned long)breakinst) {
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    registers[PC] = registers[NPC];
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    registers[NPC] += 4;
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  }
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  /* get the last know signal number from the trap register */
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  sigval = computeSignal((registers[TBR] >> 4) & 0xff);
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  /* call the main command processing loop for gdb */
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  gdb_event_loop (sigval, registers);
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}
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/*
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 * This function will generate a breakpoint exception.  It is used at the
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 * beginning of a program to sync up with a debugger and can be used
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 * otherwise as a quick means to stop program execution and "break" into
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 * the debugger.
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 */
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void
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breakpoint()
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{
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  DEBUG (1, "Entering breakpoint()");
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  if (!initialized)
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    return;
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  asm("	.globl " STRINGSYM(breakinst) "		\n\
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	" STRINGSYM(breakinst) ": ta 128+1	\n\
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	nop					\n\
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	nop					\n\
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      ");
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}
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/*
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 * This is just a test vector for debugging excpetions.
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 */
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void
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bad_trap(tt)
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int tt;
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{
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  print ("Got a bad trap #");
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  outbyte (tt);
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  outbyte ('\n');
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  asm("ta 0		\n\
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	nop		\n\
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	nop		\n\
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      ");
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}
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/*
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 * This is just a test vector for debugging excpetions.
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 */
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void
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soft_trap(tt)
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int tt;
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{
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  print ("Got a soft trap #");
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  outbyte (tt);
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  outbyte ('\n');
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  asm("ta 0		\n\
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	nop		\n\
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	nop		\n\
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      ");
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}
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/*
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 * Flush the instruction cache.  We need to do this for the debugger stub so
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 * that breakpoints, et. al. become visible to the instruction stream after
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 * storing them in memory.
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 * 
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 * For the sparclite, we need to do something here, but for a standard
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 * sparc (which SIS simulates), we don't.
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 */
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void
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flush_i_cache ()
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{
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}
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/*
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 * This will reset the processor, so we never return from here.
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 */
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void
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target_reset()
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{
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  asm ("call 0		\n\
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	nop ");
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}
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/*
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 * g - read registers.
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 *	no params.
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 *	returns a vector of words, size is NUM_REGS.
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 */
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char *
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target_read_registers(unsigned long *registers)
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{
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  char *ptr;
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  unsigned long *sp;
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  DEBUG (1, "In target_read_registers()");
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  ptr = packet_out_buf;
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  ptr = mem2hex((char *)registers, ptr, 16 * 4, 0); /* G & O regs */
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  ptr = mem2hex((unsigned char *)(sp + 0), ptr, 16 * 4, 0); /* L & I regs */
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  memset(ptr, '0', 32 * 8); /* Floating point */
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  mem2hex((char *)®isters[Y],
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	  ptr + 32 * 4 * 2,
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	  8 * 4,
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	  0);		/* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
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  return (ptr);
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}
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/*
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 * G - write registers.
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 *	param is a vector of words, size is NUM_REGS.
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 *	returns an OK or an error number.
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 */
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char *
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target_write_registers(unsigned long *registers)
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{	
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  unsigned char *ptr;
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  unsigned long *sp;
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  unsigned long *newsp, psr;
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  DEBUG (1, "In target_write_registers()");
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  psr = registers[PSR];
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  ptr = &packet_in_buf[1];
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  hex2mem(ptr, (char *)registers, 16 * 4, 0); /* G & O regs */
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  hex2mem(ptr + 16 * 4 * 2, (unsigned char *)(sp + 0), 16 * 4, 0); /* L & I regs */
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  hex2mem(ptr + 64 * 4 * 2, (char *)®isters[Y],
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	  8 * 4, 0);	/* Y, PSR, WIM, TBR, PC, NPC, FPSR, CPSR */
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  /*
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   * see if the stack pointer has moved.  If so, then copy the saved
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   * locals and ins to the new location.  This keeps the window
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   * overflow and underflow routines happy.
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   */
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  newsp = (unsigned long *)registers[SP];
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  if (sp != newsp)
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    sp = memcpy(newsp, sp, 16 * 4);
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  /* Don't allow CWP to be modified. */
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  if (psr != registers[PSR])
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    registers[PSR] = (psr & 0x1f) | (registers[PSR] & ~0x1f);
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  return (ptr);
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}
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char *
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target_dump_state(unsigned long *registers)
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{
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  int tt;			/* Trap type */
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  int sigval;
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  char *ptr;
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  unsigned long *sp;
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  DEBUG (1, "In target_dump_state()");
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  sp = (unsigned long *)registers[SP];
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  tt = (registers[TBR] >> 4) & 0xff;
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  /* reply to host that an exception has occurred */
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  sigval = computeSignal(tt);
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  ptr = packet_out_buf;
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  *ptr++ = 'T';
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  *ptr++ = hexchars[sigval >> 4];
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  *ptr++ = hexchars[sigval & 0xf];
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  *ptr++ = hexchars[PC >> 4];
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  *ptr++ = hexchars[PC & 0xf];
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  *ptr++ = ':';
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  ptr = mem2hex((unsigned char *)®isters[PC], ptr, 4, 0);
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  *ptr++ = ';';
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  *ptr++ = hexchars[FP >> 4];
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  *ptr++ = hexchars[FP & 0xf];
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  *ptr++ = ':';
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  ptr = mem2hex((unsigned char *)(sp + 8 + 6), ptr, 4, 0); /* FP */
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  *ptr++ = ';';
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  *ptr++ = hexchars[SP >> 4];
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  *ptr++ = hexchars[SP & 0xf];
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  *ptr++ = ':';
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  ptr = mem2hex((unsigned char *)&sp, ptr, 4, 0);
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  *ptr++ = ';';
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  *ptr++ = hexchars[NPC >> 4];
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  return (packet_out_buf);
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}
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void
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write_pc(unsigned long *registers, unsigned long addr)
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{
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  DEBUG (1, "In write_pc");
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  registers[PC] = addr;
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  registers[NPC] = addr + 4;
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}
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