root/kernel/FPU-emu/reg_constant.c

/* */

DEFINITIONS

1. fld_const
2. fld1
3. fldl2t
4. fldl2e
5. fldpi
6. fldlg2
7. fldln2
8. fldz
9. fconst

   1 /*---------------------------------------------------------------------------+
   2  |  reg_constant.c                                                           |
   3  |                                                                           |
   4  | All of the constant FPU_REGs                                              |
   5  |                                                                           |
   6  | Copyright (C) 1992    W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   7  |                       Australia.  E-mail apm233m@vaxc.cc.monash.edu.au    |
   8  |                                                                           |
   9  |                                                                           |
  10  +---------------------------------------------------------------------------*/
  11 
  12 #include "fpu_system.h"
  13 #include "fpu_emu.h"
  14 #include "status_w.h"
  15 #include "reg_constant.h"
  16 
  17 
  18 FPU_REG CONST_1    = { SIGN_POS, TW_Valid, EXP_BIAS,
  19                             0x00000000, 0x80000000 };
  20 FPU_REG CONST_2    = { SIGN_POS, TW_Valid, EXP_BIAS+1,
  21                             0x00000000, 0x80000000 };
  22 FPU_REG CONST_HALF = { SIGN_POS, TW_Valid, EXP_BIAS-1,
  23                             0x00000000, 0x80000000 };
  24 FPU_REG CONST_L2T  = { SIGN_POS, TW_Valid, EXP_BIAS+1,
  25                             0xcd1b8afe, 0xd49a784b };
  26 FPU_REG CONST_L2E  = { SIGN_POS, TW_Valid, EXP_BIAS,
  27                             0x5c17f0bc, 0xb8aa3b29 };
  28 FPU_REG CONST_PI   = { SIGN_POS, TW_Valid, EXP_BIAS+1,
  29                             0x2168c235, 0xc90fdaa2 };
  30 FPU_REG CONST_PI2  = { SIGN_POS, TW_Valid, EXP_BIAS,
  31                             0x2168c235, 0xc90fdaa2 };
  32 FPU_REG CONST_PI4  = { SIGN_POS, TW_Valid, EXP_BIAS-1,
  33                             0x2168c235, 0xc90fdaa2 };
  34 FPU_REG CONST_LG2  = { SIGN_POS, TW_Valid, EXP_BIAS-2,
  35                             0xfbcff799, 0x9a209a84 };
  36 FPU_REG CONST_LN2  = { SIGN_POS, TW_Valid, EXP_BIAS-1,
  37                             0xd1cf79ac, 0xb17217f7 };
  38 
  39 /* Only the sign (and tag) is used in internal zeroes */
  40 FPU_REG CONST_Z    = { SIGN_POS, TW_Zero, 0,          0x0,        0x0 };
  41 
  42 /* Only the sign and significand (and tag) are used in internal NaNs */
  43 /* The 80486 never generates one of these 
  44 FPU_REG CONST_SNAN = { SIGN_POS, TW_NaN, EXP_OVER, 0x00000001, 0x80000000 };
  45  */
  46 /* This is the real indefinite QNaN */
  47 FPU_REG CONST_QNaN = { SIGN_NEG, TW_NaN, EXP_OVER, 0x00000000, 0xC0000000 };
  48 
  49 /* Only the sign (and tag) is used in internal infinities */
  50 FPU_REG CONST_INF  = { SIGN_POS, TW_Infinity, EXP_OVER, 0x00000000, 0x80000000 };
  51 
  52 
  53 
  54 static void fld_const(FPU_REG *c)
     /*  */
  55 {
  56   FPU_REG *st_new_ptr;
  57 
  58   if ( STACK_OVERFLOW )
  59     {
  60       stack_overflow();
  61       return;
  62     }
  63   push();
  64   reg_move(c, FPU_st0_ptr);
  65   status_word &= ~SW_C1;
  66 }
  67 
  68 
  69 static void fld1(void)
     /*  */
  70 {
  71   fld_const(&CONST_1);
  72 }
  73 
  74 static void fldl2t(void)
     /*  */
  75 {
  76   fld_const(&CONST_L2T);
  77 }
  78 
  79 static void fldl2e(void)
     /*  */
  80 {
  81   fld_const(&CONST_L2E);
  82 }
  83 
  84 static void fldpi(void)
     /*  */
  85 {
  86   fld_const(&CONST_PI);
  87 }
  88 
  89 static void fldlg2(void)
     /*  */
  90 {
  91   fld_const(&CONST_LG2);
  92 }
  93 
  94 static void fldln2(void)
     /*  */
  95 {
  96   fld_const(&CONST_LN2);
  97 }
  98 
  99 static void fldz(void)
     /*  */
 100 {
 101   fld_const(&CONST_Z);
 102 }
 103 
 104 static FUNC constants_table[] = {
 105   fld1, fldl2t, fldl2e, fldpi, fldlg2, fldln2, fldz, Un_impl
 106 };
 107 
 108 void fconst(void)
     /*  */
 109 {
 110   (constants_table[FPU_rm])();
 111 }

/* */