/*---------------------------------------------------------------------------+ |  fpu_aux.c                                                                | |                                                                           | | Code to implement some of the FPU auxiliary instructions.                 | |                                                                           | | Copyright (C) 1992,1993,1994                                              | |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      | |                       Australia.  E-mail   billm@vaxc.cc.monash.edu.au    | |                                                                           | |                                                                           | +---------------------------------------------------------------------------*/#include "fpu_system.h"#include "exception.h"#include "fpu_emu.h"#include "status_w.h"#include "control_w.h"static void fnop(void){}void fclex(void){  partial_status &= ~(SW_Backward|SW_Summary|SW_Stack_Fault|SW_Precision|		   SW_Underflow|SW_Overflow|SW_Zero_Div|SW_Denorm_Op|		   SW_Invalid);  NO_NET_DATA_EFFECT;  FPU_entry_eip = ip_offset;               /* We want no net effect */}/* Needs to be externally visible */void finit(){  int r;  control_word = 0x037f;  partial_status = 0;  top = 0;            /* We don't keep top in the status word internally. */  for (r = 0; r < 8; r++)    {      regs[r].tag = TW_Empty;    }  /* The behaviour is different to that detailed in     Section 15.1.6 of the Intel manual */  data_operand_offset = 0;  operand_selector = 0;  NO_NET_DATA_EFFECT;  FPU_entry_op_cs = 0;  FPU_entry_eip = ip_offset = 0;}/* * These are nops on the i387.. */#define feni fnop#define fdisi fnop#define fsetpm fnopstatic FUNC const finit_table[] = {  feni, fdisi, fclex, finit,  fsetpm, FPU_illegal, FPU_illegal, FPU_illegal};void finit_(){  (finit_table[FPU_rm])();}static void fstsw_ax(void){  *(short *) &FPU_EAX = status_word();  NO_NET_INSTR_EFFECT;}static FUNC const fstsw_table[] = {  fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal,  FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal};void fstsw_(){  (fstsw_table[FPU_rm])();}static FUNC const fp_nop_table[] = {  fnop, FPU_illegal, FPU_illegal, FPU_illegal,  FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal};void fp_nop(){  (fp_nop_table[FPU_rm])();}void fld_i_(){  FPU_REG *st_new_ptr;  if ( STACK_OVERFLOW )    { stack_overflow(); return; }  /* fld st(i) */  if ( NOT_EMPTY(FPU_rm) )    { reg_move(&st(FPU_rm), st_new_ptr); push(); }  else    {      if ( control_word & EX_Invalid )	{	  /* The masked response */	  push();	  stack_underflow();	}      else	EXCEPTION(EX_StackUnder);    }}void fxch_i(){  /* fxch st(i) */  FPU_REG t;  register FPU_REG *sti_ptr = &st(FPU_rm);  if ( FPU_st0_tag == TW_Empty )    {      if ( sti_ptr->tag == TW_Empty )	{	  stack_underflow();	  stack_underflow_i(FPU_rm);	  return;	}      if ( control_word & CW_Invalid )	reg_move(sti_ptr, FPU_st0_ptr);   /* Masked response */      stack_underflow_i(FPU_rm);      return;    }  if ( sti_ptr->tag == TW_Empty )    {      if ( control_word & CW_Invalid )	reg_move(FPU_st0_ptr, sti_ptr);   /* Masked response */      stack_underflow();      return;    }  clear_C1();  reg_move(FPU_st0_ptr, &t);  reg_move(sti_ptr, FPU_st0_ptr);  reg_move(&t, sti_ptr);}void ffree_(){  /* ffree st(i) */  st(FPU_rm).tag = TW_Empty;}void ffreep(){  /* ffree st(i) + pop - unofficial code */  st(FPU_rm).tag = TW_Empty;  pop();}void fst_i_(){  /* fst st(i) */  reg_move(FPU_st0_ptr, &st(FPU_rm));}void fstp_i(){  /* fstp st(i) */  reg_move(FPU_st0_ptr, &st(FPU_rm));  pop();}