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 #ifdef _M_AMD64
  27 unsigned int __getfpcw87(void);
  28 void __setfpcw87(unsigned int);
  29 #endif
  30
  31 /*
  32  * @implemented
  33  */
  34
  35 unsigned int CDECL _controlfp(unsigned int newval, unsigned int mask)
  36 {
  37   return _control87( newval, mask & ~_EM_DENORMAL );
  38 }
  39
  40 /*********************************************************************
  41  *              _control87 (MSVCRT.@)
  42  */
  43 unsigned int CDECL _control87(unsigned int newval, unsigned int mask)
  44 {
  45   unsigned int fpword = 0;
  46   unsigned int flags = 0;
  47
  48   TRACE("(%08x, %08x): Called\n", newval, mask);
  49
  50   /* Get fp control word */
  51 #ifdef _M_AMD64
  52   fpword = __getfpcw87();
  53 #elif defined(__GNUC__)
  54   __asm__ __volatile__( "fstcw %0" : "=m" (fpword) : );
  55 #else
  56   __asm fstcw [fpword];
  57 #endif
  58
  59   TRACE("Control word before : %08x\n", fpword);
  60
  61   /* Convert into mask constants */
  62   if (fpword & 0x1)  flags |= _EM_INVALID;
  63   if (fpword & 0x2)  flags |= _EM_DENORMAL;
  64   if (fpword & 0x4)  flags |= _EM_ZERODIVIDE;
  65   if (fpword & 0x8)  flags |= _EM_OVERFLOW;
  66   if (fpword & 0x10) flags |= _EM_UNDERFLOW;
  67   if (fpword & 0x20) flags |= _EM_INEXACT;
  68   switch(fpword & 0xC00) {
  69   case 0xC00: flags |= _RC_UP|_RC_DOWN; break;
  70   case 0x800: flags |= _RC_UP; break;
  71   case 0x400: flags |= _RC_DOWN; break;
  72   }
  73   switch(fpword & 0x300) {
  74   case 0x0:   flags |= _PC_24; break;
  75   case 0x200: flags |= _PC_53; break;
  76   case 0x300: flags |= _PC_64; break;
  77   }
  78   if (fpword & 0x1000) flags |= _IC_AFFINE;
  79
  80   /* Mask with parameters */
  81   flags = (flags & ~mask) | (newval & mask);
  82
  83   /* Convert (masked) value back to fp word */
  84   fpword = 0;
  85   if (flags & _EM_INVALID)    fpword |= 0x1;
  86   if (flags & _EM_DENORMAL)   fpword |= 0x2;
  87   if (flags & _EM_ZERODIVIDE) fpword |= 0x4;
  88   if (flags & _EM_OVERFLOW)   fpword |= 0x8;
  89   if (flags & _EM_UNDERFLOW)  fpword |= 0x10;
  90   if (flags & _EM_INEXACT)    fpword |= 0x20;
  91   switch(flags & (_RC_UP | _RC_DOWN)) {
  92   case _RC_UP|_RC_DOWN: fpword |= 0xC00; break;
  93   case _RC_UP:          fpword |= 0x800; break;
  94   case _RC_DOWN:        fpword |= 0x400; break;
  95   }
  96   switch (flags & (_PC_24 | _PC_53)) {
  97   case _PC_64: fpword |= 0x300; break;
  98   case _PC_53: fpword |= 0x200; break;
  99   case _PC_24: fpword |= 0x0; break;
 100   }
 101   if (flags & _IC_AFFINE) fpword |= 0x1000;
 102
 103   TRACE("Control word after  : %08x\n", fpword);
 104
 105   /* Put fp control word */
 106 #ifdef _M_AMD64
 107   __setfpcw87(fpword);
 108 #elif defined(__GNUC__)
 109   __asm__ __volatile__( "fldcw %0" : : "m" (fpword) );
 110 #else
 111   __asm fldcw [fpword];
 112 #endif
 113
 114   return flags;
 115 }
 116
 117 /*********************************************************************
 118  *              _controlfp_s (MSVCRT.@)
 119  */
 120 int CDECL _controlfp_s(unsigned int *cur, unsigned int newval, unsigned int mask)
 121 {
 122 #ifdef __i386__
 123     unsigned int flags;
 124
 125     FIXME("(%p %u %u) semi-stub\n", cur, newval, mask);
 126
 127     flags = _control87( newval, mask & ~_EM_DENORMAL );
 128
 129     if(cur)
 130         *cur = flags;
 131
 132     return 0;
 133 #else
 134     FIXME(":Not Implemented!\n");
 135     return 0;
 136 #endif
 137 }