arch/i386/math-emu/reg

/* */
This source file includes following definitions.
fld_const
fld1
fldl2t
fldl2e
fldpi
fldlg2
fldln2
fldz
fconst
   1 /*---------------------------------------------------------------------------+
   2  |  reg_constant.c                                                           |
   3  |                                                                           |
   4  | All of the constant FPU_REGs                                              |
   5  |                                                                           |
   6  | Copyright (C) 1992,1993,1994,1996                                         |
   7  |                     W. Metzenthen, 22 Parker St, Ormond, Vic 3163,        |
   8  |                     Australia.  E-mail   billm@jacobi.maths.monash.edu.au |
   9  |                                                                           |
  10  |                                                                           |
  11  +---------------------------------------------------------------------------*/
  12 
  13 #include "fpu_system.h"
  14 #include "fpu_emu.h"
  15 #include "status_w.h"
  16 #include "reg_constant.h"
  17 #include "control_w.h"
  18 
  19 
  20 FPU_REG const CONST_1    = { SIGN_POS, TW_Valid, EXP_BIAS,
  21                             0x00000000, 0x80000000 };
  22 FPU_REG const CONST_2    = { SIGN_POS, TW_Valid, EXP_BIAS+1,
  23                             0x00000000, 0x80000000 };
  24 FPU_REG const CONST_HALF = { SIGN_POS, TW_Valid, EXP_BIAS-1,
  25                             0x00000000, 0x80000000 };
  26 FPU_REG const CONST_L2T  = { SIGN_POS, TW_Valid, EXP_BIAS+1,
  27                             0xcd1b8afe, 0xd49a784b };
  28 FPU_REG const CONST_L2E  = { SIGN_POS, TW_Valid, EXP_BIAS,
  29                             0x5c17f0bc, 0xb8aa3b29 };
  30 FPU_REG const CONST_PI   = { SIGN_POS, TW_Valid, EXP_BIAS+1,
  31                             0x2168c235, 0xc90fdaa2 };
  32 FPU_REG const CONST_PI2  = { SIGN_POS, TW_Valid, EXP_BIAS,
  33                             0x2168c235, 0xc90fdaa2 };
  34 FPU_REG const CONST_PI4  = { SIGN_POS, TW_Valid, EXP_BIAS-1,
  35                             0x2168c235, 0xc90fdaa2 };
  36 FPU_REG const CONST_LG2  = { SIGN_POS, TW_Valid, EXP_BIAS-2,
  37                             0xfbcff799, 0x9a209a84 };
  38 FPU_REG const CONST_LN2  = { SIGN_POS, TW_Valid, EXP_BIAS-1,
  39                             0xd1cf79ac, 0xb17217f7 };
  40 
  41 /* Extra bits to take pi/2 to more than 128 bits precision. */
  42 FPU_REG const CONST_PI2extra = { SIGN_NEG, TW_Valid, EXP_BIAS-66,
  43                             0xfc8f8cbb, 0xece675d1 };
  44 
  45 /* Only the sign (and tag) is used in internal zeroes */
  46 FPU_REG const CONST_Z    = { SIGN_POS, TW_Zero, EXP_UNDER, 0x0, 0x0 };
  47 
  48 /* Only the sign and significand (and tag) are used in internal NaNs */
  49 /* The 80486 never generates one of these 
  50 FPU_REG const CONST_SNAN = { SIGN_POS, TW_NaN, EXP_OVER, 0x00000001, 0x80000000 };
  51  */
  52 /* This is the real indefinite QNaN */
  53 FPU_REG const CONST_QNaN = { SIGN_NEG, TW_NaN, EXP_OVER, 0x00000000, 0xC0000000 };
  54 
  55 /* Only the sign (and tag) is used in internal infinities */
  56 FPU_REG const CONST_INF  = { SIGN_POS, TW_Infinity, EXP_OVER, 0x00000000, 0x80000000 };
  57 
  58 
  59 
  60 static void fld_const(FPU_REG const *c, int adj)
     /*  */
  61 {
  62   FPU_REG *st_new_ptr;
  63 
  64   if ( STACK_OVERFLOW )
  65     {
  66       stack_overflow();
  67       return;
  68     }
  69   push();
  70   reg_move(c, st_new_ptr);
  71   st_new_ptr->sigl += adj;  /* For all our fldxxx constants, we don't need to
  72                                borrow or carry. */
  73   clear_C1();
  74 }
  75 
  76 /* A fast way to find out whether x is one of RC_DOWN or RC_CHOP
  77    (and not one of RC_RND or RC_UP).
  78    */
  79 #define DOWN_OR_CHOP(x)  (x & RC_DOWN)
  80 
  81 static void fld1(int rc)
     /*  */
  82 {
  83   fld_const(&CONST_1, 0);
  84 }
  85 
  86 static void fldl2t(int rc)
     /*  */
  87 {
  88   fld_const(&CONST_L2T, (rc == RC_UP) ? 1 : 0);
  89 }
  90 
  91 static void fldl2e(int rc)
     /*  */
  92 {
  93   fld_const(&CONST_L2E, DOWN_OR_CHOP(rc) ? -1 : 0);
  94 }
  95 
  96 static void fldpi(int rc)
     /*  */
  97 {
  98   fld_const(&CONST_PI, DOWN_OR_CHOP(rc) ? -1 : 0);
  99 }
 100 
 101 static void fldlg2(int rc)
     /*  */
 102 {
 103   fld_const(&CONST_LG2, DOWN_OR_CHOP(rc) ? -1 : 0);
 104 }
 105 
 106 static void fldln2(int rc)
     /*  */
 107 {
 108   fld_const(&CONST_LN2, DOWN_OR_CHOP(rc) ? -1 : 0);
 109 }
 110 
 111 static void fldz(int rc)
     /*  */
 112 {
 113   fld_const(&CONST_Z, 0);
 114 }
 115 
 116 typedef void (*FUNC_RC)(int);
 117 
 118 static FUNC_RC constants_table[] = {
 119   fld1, fldl2t, fldl2e, fldpi, fldlg2, fldln2, fldz, (FUNC_RC)FPU_illegal
 120 };
 121 
 122 void fconst(void)
     /*  */
 123 {
 124   (constants_table[FPU_rm])(control_word & CW_RC);
 125 }
/* */
root/arch/i386/math-emu/reg_constant.c

DEFINITIONS
