reactos/lib/sdk/crt/float/i386/cntrlfp.c

   1 /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
   2
   3 #include <precomp.h>
   4 #include <float.h>
   5
   6 #define X87_CW_IM   (1<<0)      /* Invalid operation mask */
   7 #define X87_CW_DM   (1<<1)      /* Denormal operand mask */
   8 #define X87_CW_ZM   (1<<2)      /* Zero divide mask */
   9 #define X87_CW_OM   (1<<3)      /* Overflow mask */
  10 #define X87_CW_UM   (1<<4)      /* Underflow mask */
  11 #define X87_CW_PM   (1<<5)      /* Precision mask */
  12
  13 #define X87_CW_PC_MASK     (3<<8)   /* precision control mask */
  14 #define X87_CW_PC24        (0<<8)   /* 24 bit precision */
  15 #define X87_CW_PC53        (2<<8)   /* 53 bit precision */
  16 #define X87_CW_PC64        (3<<8)   /* 64 bit precision */
  17
  18 #define X87_CW_RC_MASK     (3<<10)  /* rounding control mask */
  19 #define X87_CW_RC_NEAREST  (0<<10)  /* round to nearest */
  20 #define X87_CW_RC_DOWN     (1<<10)  /* round down */
  21 #define X87_CW_RC_UP       (2<<10)  /* round up */
  22 #define X87_CW_RC_ZERO     (3<<10)  /* round toward zero (chop) */
  23
  24 #define X87_CW_IC          (1<<12)  /* infinity control flag */
  25
  26 /*
  27  * @implemented
  28  */
  29
  30 unsigned int CDECL _controlfp(unsigned int newval, unsigned int mask)
  31 {
  32   return _control87( newval, mask & ~_EM_DENORMAL );
  33 }
  34
  35 /*********************************************************************
  36  *              _control87 (MSVCRT.@)
  37  */
  38 unsigned int CDECL _control87(unsigned int newval, unsigned int mask)
  39 {
  40   unsigned int fpword = 0;
  41   unsigned int flags = 0;
  42
  43   TRACE("(%08x, %08x): Called\n", newval, mask);
  44
  45   /* Get fp control word */
  46 #if defined(__GNUC__)
  47   __asm__ __volatile__( "fstcw %0" : "=m" (fpword) : );
  48 #else
  49   __asm fstcw [fpword];
  50 #endif
  51
  52   TRACE("Control word before : %08x\n", fpword);
  53
  54   /* Convert into mask constants */
  55   if (fpword & 0x1)  flags |= _EM_INVALID;
  56   if (fpword & 0x2)  flags |= _EM_DENORMAL;
  57   if (fpword & 0x4)  flags |= _EM_ZERODIVIDE;
  58   if (fpword & 0x8)  flags |= _EM_OVERFLOW;
  59   if (fpword & 0x10) flags |= _EM_UNDERFLOW;
  60   if (fpword & 0x20) flags |= _EM_INEXACT;
  61   switch(fpword & 0xC00) {
  62   case 0xC00: flags |= _RC_UP|_RC_DOWN; break;
  63   case 0x800: flags |= _RC_UP; break;
  64   case 0x400: flags |= _RC_DOWN; break;
  65   }
  66   switch(fpword & 0x300) {
  67   case 0x0:   flags |= _PC_24; break;
  68   case 0x200: flags |= _PC_53; break;
  69   case 0x300: flags |= _PC_64; break;
  70   }
  71   if (fpword & 0x1000) flags |= _IC_AFFINE;
  72
  73   /* Mask with parameters */
  74   flags = (flags & ~mask) | (newval & mask);
  75
  76   /* Convert (masked) value back to fp word */
  77   fpword = 0;
  78   if (flags & _EM_INVALID)    fpword |= 0x1;
  79   if (flags & _EM_DENORMAL)   fpword |= 0x2;
  80   if (flags & _EM_ZERODIVIDE) fpword |= 0x4;
  81   if (flags & _EM_OVERFLOW)   fpword |= 0x8;
  82   if (flags & _EM_UNDERFLOW)  fpword |= 0x10;
  83   if (flags & _EM_INEXACT)    fpword |= 0x20;
  84   switch(flags & (_RC_UP | _RC_DOWN)) {
  85   case _RC_UP|_RC_DOWN: fpword |= 0xC00; break;
  86   case _RC_UP:          fpword |= 0x800; break;
  87   case _RC_DOWN:        fpword |= 0x400; break;
  88   }
  89   switch (flags & (_PC_24 | _PC_53)) {
  90   case _PC_64: fpword |= 0x300; break;
  91   case _PC_53: fpword |= 0x200; break;
  92   case _PC_24: fpword |= 0x0; break;
  93   }
  94   if (flags & _IC_AFFINE) fpword |= 0x1000;
  95
  96   TRACE("Control word after  : %08x\n", fpword);
  97
  98   /* Put fp control word */
  99 #if defined(__GNUC__)
 100   __asm__ __volatile__( "fldcw %0" : : "m" (fpword) );
 101 #else
 102   __asm fldcw [fpword];
 103 #endif
 104
 105   return flags;
 106 }
 107
 108 /*********************************************************************
 109  *              _controlfp_s (MSVCRT.@)
 110  */
 111 int CDECL _controlfp_s(unsigned int *cur, unsigned int newval, unsigned int mask)
 112 {
 113 #ifdef __i386__
 114     unsigned int flags;
 115
 116     FIXME("(%p %u %u) semi-stub\n", cur, newval, mask);
 117
 118     flags = _control87( newval, mask & ~_EM_DENORMAL );
 119
 120     if(cur)
 121         *cur = flags;
 122
 123     return 0;
 124 #else
 125     FIXME(":Not Implemented!\n");
 126     return 0;
 127 #endif
 128 }