/* x86-arch.c -*- Mode: C; comment-column: 40 -*-
 *
 * $Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/lisp/amd64-arch.c,v 1.1 2004/05/18 21:53:56 cwang Exp $ 
 *
 */

#include <stdio.h>

#include "lisp.h"
#include "globals.h"
#include "validate.h"
#include "os.h"
#include "internals.h"
#include "arch.h"
#include "lispregs.h"
#include "signal.h"
#include "alloc.h"
#include "interrupt.h"
#include "interr.h"
#include "breakpoint.h"

#define DPRINTF(test, e) {if(test) fprintf e ;}

#define BREAKPOINT_INST 0xcc	/* INT3 */

unsigned long  fast_random_state = 1;

char * arch_init(void)
{
  return "lisp.core";
}



/*
 * Assuming we get here via an INT3 xxx instruction, the PC now
 * points to the interrupt code (lisp value) so we just move past
 * it. Skip the code, then if the code is an error-trap or
 * Cerror-trap then skip the data bytes that follow.
 */

void arch_skip_instruction(struct sigcontext *context)
{
  int vlen,code;

  DPRINTF(0,(stderr,"[arch_skip_inst at %x>]\n", context->sc_pc));

  /* Get and skip the lisp error code. */
  code = *(char*) context->sc_pc++;
  switch (code)
    {
    case trap_Error:
    case trap_Cerror:
      /* Lisp error arg vector length */
      vlen = *(char*) context->sc_pc++;
      /* Skip lisp error arg data bytes */
      while(vlen-- > 0) 
	((char*) context->sc_pc)++;
      break;

    case trap_Breakpoint:
    case trap_FunctionEndBreakpoint:
      break;

    case trap_PendingInterrupt:
    case trap_Halt:
      /* Only needed to skip the Code. */
      break;

    default:
      fprintf(stderr, "[arch_skip_inst invalid code %d\n]\n", code);
      break;
    }

  DPRINTF(0,(stderr,"[arch_skip_inst resuming at %x>]\n", context->sc_pc));
}

unsigned char * arch_internal_error_arguments(struct sigcontext *context)
{
  return (unsigned char *) (context->sc_pc + 1);
}

boolean arch_pseudo_atomic_atomic(struct sigcontext *context)
{
  return SymbolValue(PSEUDO_ATOMIC_ATOMIC);
}

void arch_set_pseudo_atomic_interrupted(struct sigcontext *context)
{
  SetSymbolValue(PSEUDO_ATOMIC_INTERRUPTED, make_fixnum(1));
}



unsigned long  arch_install_breakpoint(void *pc)
{
  unsigned long result = *(unsigned long*)pc;

  *(char*)pc = BREAKPOINT_INST;		/* x86 INT3       */
  *((char*)pc+1) = trap_Breakpoint;	/* Lisp trap code */
  
  return result;
}

void  arch_remove_breakpoint(void *pc, unsigned long orig_inst)
{
  *((char *) pc) = orig_inst & 0xff;
  *((char *) pc + 1) = (orig_inst & 0xff00) >> 8;
}



/*
 * When single stepping single_stepping holds the original instruction
 * pc location.
 */

unsigned int *single_stepping = NULL;
#ifndef __linux__
unsigned int  single_step_save1;
unsigned int  single_step_save2;
unsigned int  single_step_save3;
#endif

void  arch_do_displaced_inst(struct sigcontext *context,
			     unsigned long orig_inst)
{
  unsigned int *pc = (unsigned int*) context->sc_pc;

  /*
   * Put the original instruction back.
   */

  *((char *) pc) = orig_inst & 0xff;
  *((char *) pc + 1) = (orig_inst & 0xff00) >> 8;

#ifdef __linux__
  context->eflags |= 0x100;
#else

  /*
   * Install helper instructions for the single step:
   * 	pushf; or [esp],0x100; popf.
   */

  single_step_save1 = *(pc - 3);
  single_step_save2 = *(pc - 2);
  single_step_save3 = *(pc - 1);
  *(pc - 3) = 0x9c909090;
  *(pc - 2) = 0x00240c81;
  *(pc - 1) = 0x9d000001;
#endif

  single_stepping = (unsigned int*) pc;

#ifndef __linux__
  (unsigned int*) context->sc_pc = (char *) pc - 9;
#endif
}


void  sigtrap_handler(HANDLER_ARGS)
{
  unsigned int  trap;
  
#ifdef __linux__
  GET_CONTEXT
#endif

#if 0
  fprintf(stderr,"x86sigtrap: %8x %x\n",
	  context->sc_pc, *(unsigned char *)(context->sc_pc-1));
  fprintf(stderr,"sigtrap(%d %d %x)\n",signal,code,context);
#endif

  if (single_stepping && (signal == SIGTRAP))
    {
#if 0
      fprintf(stderr,"* Single step trap %x\n", single_stepping);
#endif

#ifndef __linux__
      /* Un-install single step helper instructions. */
      *(single_stepping-3) = single_step_save1;
      *(single_stepping-2) = single_step_save2;
      *(single_stepping-1) = single_step_save3;
#else  
       context->eflags ^= 0x100;
#endif

      /*
       * Re-install the breakpoint if possible.
       */

      if ((int) context->sc_pc == (int) single_stepping + 1)
	fprintf(stderr, "* Breakpoint not re-install\n");
      else
	{
	  char *ptr = (char *) single_stepping;
	  ptr[0] = BREAKPOINT_INST;	/* x86 INT3 */
	  ptr[1] = trap_Breakpoint;
	}

      single_stepping = NULL;
      return;
    }

  SAVE_CONTEXT();

  /* This is just for info in case monitor wants to print an approx */
  current_control_stack_pointer = (unsigned long*) context->sc_sp;

#if defined(__linux__) && (defined(i386) || defined(__x86_64))
  /*
   * Restore the FPU control word, setting the rounding mode to nearest.
   */

  if (contextstruct.fpstate)
#if defined(__x86_64)
    setfpucw(contextstruct.fpstate->cwd & ~0xc00);
#else
    setfpucw(contextstruct.fpstate->cw & ~0xc00);
#endif
#endif

 /*
  * On entry %eip points just after the INT3 byte and aims at the
  * 'kind' value (eg trap_Cerror). For error-trap and Cerror-trap a
  * number of bytes will follow, the first is the length of the byte
  * arguments to follow.
  */

  trap = *(unsigned char *) (context->sc_pc);

  switch (trap)
    {
    case trap_PendingInterrupt:
      DPRINTF(0,(stderr,"<trap Pending Interrupt.>\n"));
      arch_skip_instruction(context);
      interrupt_handle_pending(context);
      break;
      
    case trap_Halt:
      {
#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
	int fpu_state[27];
	fpu_save(fpu_state);
#endif
	fake_foreign_function_call(context);
	lose("%%primitive halt called; the party is over.\n");
	undo_fake_foreign_function_call(context);
#if defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__NetBSD__)
	fpu_restore(fpu_state);
#endif
	arch_skip_instruction(context);
	break;
      }
      
    case trap_Error:
    case trap_Cerror:
      DPRINTF(0, (stderr, "<trap Error %d>\n",code));
#ifdef __linux__
      interrupt_internal_error(signal, contextstruct, code == trap_Cerror);
#else
      interrupt_internal_error(signal, code, context, code == trap_Cerror);
#endif
      break;

    case trap_Breakpoint:
#if 0
      fprintf(stderr,"*C break\n");
#endif
      (char*) context->sc_pc -= 1;
      handle_breakpoint(signal, code, context);
#if 0
      fprintf(stderr,"*C break return\n");
#endif
      break;
      
    case trap_FunctionEndBreakpoint:
      (char*) context->sc_pc -= 1;
      context->sc_pc = (int) handle_function_end_breakpoint(signal, code, context);
      break;
      
#ifdef trap_DynamicSpaceOverflowWarning
    case trap_DynamicSpaceOverflowWarning:
	interrupt_handle_space_overflow(SymbolFunction(DYNAMIC_SPACE_OVERFLOW_WARNING_HIT),
					context);
	break;
#endif
#ifdef trap_DynamicSpaceOverflowError
    case trap_DynamicSpaceOverflowError:
	interrupt_handle_space_overflow(SymbolFunction(DYNAMIC_SPACE_OVERFLOW_ERROR_HIT),
					context);
            break;
#endif
    default:
      DPRINTF(0,(stderr,"[C--trap default %d %d %x]\n", signal, code,context));
#ifdef __linux__
      interrupt_handle_now(signal, contextstruct);
#else
      interrupt_handle_now(signal, code, context);
#endif
      break;
    }
}

#define FIXNUM_VALUE(lispobj) (((int) lispobj) >> 2)

void arch_install_interrupt_handlers()
{
    interrupt_install_low_level_handler(SIGILL, sigtrap_handler);
    interrupt_install_low_level_handler(SIGTRAP, sigtrap_handler);
}


extern lispobj call_into_lisp(lispobj fun, lispobj *args, int nargs);

/* These next four functions are an interface to the 
 * Lisp call-in facility. Since this is C we can know
 * nothing about the calling environment. The control
 * stack might be the C stack if called from the monitor
 * or the Lisp stack if called as a result of an interrupt
 * or maybe even a separate stack. The args are most likely
 * on that stack but could be in registers depending on
 * what the compiler likes. So I try to package up the
 * args into a portable vector and let the assembly language
 * call-in function figure it out.
 */

lispobj  funcall0(lispobj function)
{
    lispobj *args = NULL;

    return call_into_lisp(function, args, 0);
}

lispobj  funcall1(lispobj function, lispobj arg0)
{
    lispobj args[1];
    args[0] = arg0;
    return call_into_lisp(function, args, 1);
}

lispobj  funcall2(lispobj function, lispobj arg0, lispobj arg1)
{
    lispobj args[2];
    args[0] = arg0;
    args[1] = arg1;
    return call_into_lisp(function, args, 2);
}

lispobj  funcall3(lispobj function, lispobj arg0, lispobj arg1, lispobj arg2)
{
    lispobj args[3];
    args[0] = arg0;
    args[1] = arg1;
    args[2] = arg2;
    return call_into_lisp(function, args, 3);
}

#ifdef LINKAGE_TABLE

#ifndef LinkageEntrySize
#define LinkageEntrySize 16
#endif

void arch_make_linkage_entry(long linkage_entry, void *target_addr, long type)
{
    char *reloc_addr = (char *)(FOREIGN_LINKAGE_SPACE_START
				+ linkage_entry * LinkageEntrySize);

    if (type == 1) {			/* code reference */
        /* Make JMP to function entry. */
	long offset = (char *)target_addr;
	int i;
	
	*reloc_addr++ = 0x49;		/* opcode for MOV */
	*reloc_addr++ = 0xbf; /* %r15 */
	for (i = 0; i < 8; i++) {
	    *reloc_addr++ = offset & 0xff;
	    offset >>= 8;
	}
	*reloc_addr++ = 0x41; /* jmpq */
	*reloc_addr++ = 0xff;
	*reloc_addr++ = 0xe7; /* %r15 */
	/* write a nop for good measure. */
	*reloc_addr = 0x90;
    } else if (type == 2) {
	*(unsigned long *)reloc_addr = (unsigned long)target_addr;
    }
}

/* Make a call to the first function in the linkage table, which is
   resolve_linkage_tramp. */
void arch_make_lazy_linkage(long linkage_entry)
{
    char *reloc_addr = (char *)(FOREIGN_LINKAGE_SPACE_START
				+ linkage_entry * LinkageEntrySize);
    long offset = (char *)(FOREIGN_LINKAGE_SPACE_START) - (reloc_addr + 5);
    int i;

    *reloc_addr++ = 0xe8;		/* opcode for CALL rel32 */
    for (i = 0; i < 4; i++) {
	*reloc_addr++ = offset & 0xff;
	offset >>= 8;
    }
    /* write a nop for good measure. */
    *reloc_addr = 0x90;
}

/* Get linkage entry.  The initial instruction in the linkage
   entry is a CALL; the return address we're passed points to the next
   instruction. */

long arch_linkage_entry(unsigned long retaddr)
{
    return ((retaddr - 5) - FOREIGN_LINKAGE_SPACE_START) / LinkageEntrySize;
}
#endif /* LINKAGE_TABLE */