kernel/FPU-emu/fpu

/* */
This source file includes following definitions.
fchs
fabs
ftst_
fxam
fp_etc
   1 /*---------------------------------------------------------------------------+
   2  |  fpu_etc.c                                                                |
   3  |                                                                           |
   4  | Implement a few FPU instructions.                                         |
   5  |                                                                           |
   6  | Copyright (C) 1992,1993                                                   |
   7  |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   8  |                       Australia.  E-mail apm233m@vaxc.cc.monash.edu.au    |
   9  |                                                                           |
  10  |                                                                           |
  11  +---------------------------------------------------------------------------*/
  12 
  13 #include "fpu_system.h"
  14 #include "exception.h"
  15 #include "fpu_emu.h"
  16 #include "status_w.h"
  17 #include "reg_constant.h"
  18 
  19 
  20 static void fchs(void)
     /*  */
  21 {
  22   if ( NOT_EMPTY_0 )
  23     {
  24       FPU_st0_ptr->sign ^= SIGN_POS^SIGN_NEG;
  25       status_word &= ~SW_C1;
  26     }
  27   else
  28     stack_underflow();
  29 }
  30 
  31 static void fabs(void)
     /*  */
  32 {
  33   if ( FPU_st0_tag ^ TW_Empty )
  34     {
  35       FPU_st0_ptr->sign = SIGN_POS;
  36       status_word &= ~SW_C1;
  37     }
  38   else
  39     stack_underflow();
  40 }
  41 
  42 
  43 static void ftst_(void)
     /*  */
  44 {
  45   switch (FPU_st0_tag)
  46     {
  47     case TW_Zero:
  48       setcc(SW_C3);
  49       break;
  50     case TW_Valid:
  51 
  52 #ifdef DENORM_OPERAND
  53       if ( (FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()) )
  54         return;
  55 #endif DENORM_OPERAND
  56 
  57       if (FPU_st0_ptr->sign == SIGN_POS)
  58         setcc(0);
  59       else
  60         setcc(SW_C0);
  61       break;
  62     case TW_NaN:
  63       setcc(SW_C0|SW_C2|SW_C3);   /* Operand is not comparable */ 
  64       EXCEPTION(EX_Invalid);
  65       break;
  66     case TW_Infinity:
  67       if (FPU_st0_ptr->sign == SIGN_POS)
  68         setcc(0);
  69       else
  70         setcc(SW_C0);
  71       EXCEPTION(EX_Invalid);
  72       break;
  73     case TW_Empty:
  74       setcc(SW_C0|SW_C2|SW_C3);
  75       EXCEPTION(EX_StackUnder);
  76       break;
  77     default:
  78       setcc(SW_C0|SW_C2|SW_C3);   /* Operand is not comparable */ 
  79       EXCEPTION(EX_INTERNAL|0x14);
  80       break;
  81     }
  82 }
  83 
  84 static void fxam(void)
     /*  */
  85 {
  86   int c=0;
  87   switch (FPU_st0_tag)
  88     {
  89     case TW_Empty:
  90       c = SW_C3|SW_C0;
  91       break;
  92     case TW_Zero:
  93       c = SW_C3;
  94       break;
  95     case TW_Valid:
  96       /* This will need to be changed if TW_Denormal is ever used. */
  97       if ( FPU_st0_ptr->exp <= EXP_UNDER )
  98         c = SW_C2|SW_C3;  /* Denormal */
  99       else
 100         c = SW_C3;
 101       break;
 102     case TW_NaN:
 103       c = SW_C0;
 104       break;
 105     case TW_Infinity:
 106       c = SW_C2|SW_C0;
 107       break;
 108     }
 109   if (FPU_st0_ptr->sign == SIGN_NEG)
 110     c |= SW_C1;
 111   setcc(c);
 112 }
 113 
 114 static FUNC fp_etc_table[] = {
 115   fchs, fabs, Un_impl, Un_impl, ftst_, fxam, Un_impl, Un_impl
 116 };
 117 
 118 void fp_etc()
     /*  */
 119 {
 120   (fp_etc_table[FPU_rm])();
 121 }
/* */
root/kernel/FPU-emu/fpu_etc.c

DEFINITIONS
