qemu

fpa11_cprt.c (7676B)

---

 /*
     NetWinder Floating Point Emulator
     (c) Rebel.COM, 1998,1999
     (c) Philip Blundell, 1999
 
     Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 2 of the License, or
     (at your option) any later version.
 
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
 
     You should have received a copy of the GNU General Public License
     along with this program; if not, see <http://www.gnu.org/licenses/>.
 */
 
 #include "qemu/osdep.h"
 #include "fpa11.h"
 #include "fpu/softfloat.h"
 #include "fpopcode.h"
 #include "fpa11.inl"
 //#include "fpmodule.h"
 //#include "fpmodule.inl"
 
 unsigned int PerformFLT(const unsigned int opcode);
 unsigned int PerformFIX(const unsigned int opcode);
 
 static unsigned int
 PerformComparison(const unsigned int opcode);
 
 unsigned int EmulateCPRT(const unsigned int opcode)
 {
   unsigned int nRc = 1;
 
   //printk("EmulateCPRT(0x%08x)\n",opcode);
 
   if (opcode & 0x800000)
   {
      /* This is some variant of a comparison (PerformComparison will
 	sort out which one).  Since most of the other CPRT
 	instructions are oddball cases of some sort or other it makes
 	sense to pull this out into a fast path.  */
      return PerformComparison(opcode);
   }
 
   /* Hint to GCC that we'd like a jump table rather than a load of CMPs */
   switch ((opcode & 0x700000) >> 20)
   {
     case  FLT_CODE >> 20: nRc = PerformFLT(opcode); break;
     case  FIX_CODE >> 20: nRc = PerformFIX(opcode); break;
 
     case  WFS_CODE >> 20: writeFPSR(readRegister(getRd(opcode))); break;
     case  RFS_CODE >> 20: writeRegister(getRd(opcode),readFPSR()); break;
 
 #if 0    /* We currently have no use for the FPCR, so there's no point
 	    in emulating it. */
     case  WFC_CODE >> 20: writeFPCR(readRegister(getRd(opcode)));
     case  RFC_CODE >> 20: writeRegister(getRd(opcode),readFPCR()); break;
 #endif
 
     default: nRc = 0;
   }
 
   return nRc;
 }
 
 unsigned int PerformFLT(const unsigned int opcode)
 {
    FPA11 *fpa11 = GET_FPA11();
 
    unsigned int nRc = 1;
    SetRoundingMode(opcode);
 
    switch (opcode & MASK_ROUNDING_PRECISION)
    {
       case ROUND_SINGLE:
       {
         fpa11->fType[getFn(opcode)] = typeSingle;
         fpa11->fpreg[getFn(opcode)].fSingle =
 	   int32_to_float32(readRegister(getRd(opcode)), &fpa11->fp_status);
       }
       break;
 
       case ROUND_DOUBLE:
       {
         fpa11->fType[getFn(opcode)] = typeDouble;
         fpa11->fpreg[getFn(opcode)].fDouble =
             int32_to_float64(readRegister(getRd(opcode)), &fpa11->fp_status);
       }
       break;
 
       case ROUND_EXTENDED:
       {
         fpa11->fType[getFn(opcode)] = typeExtended;
         fpa11->fpreg[getFn(opcode)].fExtended =
 	   int32_to_floatx80(readRegister(getRd(opcode)), &fpa11->fp_status);
       }
       break;
 
       default: nRc = 0;
   }
 
   return nRc;
 }
 
 unsigned int PerformFIX(const unsigned int opcode)
 {
    FPA11 *fpa11 = GET_FPA11();
    unsigned int nRc = 1;
    unsigned int Fn = getFm(opcode);
 
    SetRoundingMode(opcode);
 
    switch (fpa11->fType[Fn])
    {
       case typeSingle:
       {
          writeRegister(getRd(opcode),
 	               float32_to_int32(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status));
       }
       break;
 
       case typeDouble:
       {
          //printf("F%d is 0x%" PRIx64 "\n",Fn,fpa11->fpreg[Fn].fDouble);
          writeRegister(getRd(opcode),
 	               float64_to_int32(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status));
       }
       break;
 
       case typeExtended:
       {
          writeRegister(getRd(opcode),
 	               floatx80_to_int32(fpa11->fpreg[Fn].fExtended, &fpa11->fp_status));
       }
       break;
 
       default: nRc = 0;
   }
 
   return nRc;
 }
 
 
 static __inline unsigned int
 PerformComparisonOperation(floatx80 Fn, floatx80 Fm)
 {
    FPA11 *fpa11 = GET_FPA11();
    unsigned int flags = 0;
 
    /* test for less than condition */
    if (floatx80_lt(Fn,Fm, &fpa11->fp_status))
    {
       flags |= CC_NEGATIVE;
    }
 
    /* test for equal condition */
    if (floatx80_eq_quiet(Fn,Fm, &fpa11->fp_status))
    {
       flags |= CC_ZERO;
    }
 
    /* test for greater than or equal condition */
    if (floatx80_lt(Fm,Fn, &fpa11->fp_status))
    {
       flags |= CC_CARRY;
    }
 
    writeConditionCodes(flags);
    return 1;
 }
 
 /* This instruction sets the flags N, Z, C, V in the FPSR. */
 
 static unsigned int PerformComparison(const unsigned int opcode)
 {
    FPA11 *fpa11 = GET_FPA11();
    unsigned int Fn, Fm;
    floatx80 rFn, rFm;
    int e_flag = opcode & 0x400000;	/* 1 if CxFE */
    int n_flag = opcode & 0x200000;	/* 1 if CNxx */
    unsigned int flags = 0;
 
    //printk("PerformComparison(0x%08x)\n",opcode);
 
    Fn = getFn(opcode);
    Fm = getFm(opcode);
 
    /* Check for unordered condition and convert all operands to 80-bit
       format.
       ?? Might be some mileage in avoiding this conversion if possible.
       Eg, if both operands are 32-bit, detect this and do a 32-bit
       comparison (cheaper than an 80-bit one).  */
    switch (fpa11->fType[Fn])
    {
       case typeSingle:
         //printk("single.\n");
 	if (float32_is_any_nan(fpa11->fpreg[Fn].fSingle))
 	   goto unordered;
         rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle, &fpa11->fp_status);
       break;
 
       case typeDouble:
         //printk("double.\n");
 	if (float64_is_any_nan(fpa11->fpreg[Fn].fDouble))
 	   goto unordered;
         rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble, &fpa11->fp_status);
       break;
 
       case typeExtended:
         //printk("extended.\n");
 	if (floatx80_is_any_nan(fpa11->fpreg[Fn].fExtended))
 	   goto unordered;
         rFn = fpa11->fpreg[Fn].fExtended;
       break;
 
       default: return 0;
    }
 
    if (CONSTANT_FM(opcode))
    {
      //printk("Fm is a constant: #%d.\n",Fm);
      rFm = getExtendedConstant(Fm);
      if (floatx80_is_any_nan(rFm))
         goto unordered;
    }
    else
    {
      //printk("Fm = r%d which contains a ",Fm);
       switch (fpa11->fType[Fm])
       {
          case typeSingle:
            //printk("single.\n");
 	   if (float32_is_any_nan(fpa11->fpreg[Fm].fSingle))
 	      goto unordered;
            rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle, &fpa11->fp_status);
          break;
 
          case typeDouble:
            //printk("double.\n");
 	   if (float64_is_any_nan(fpa11->fpreg[Fm].fDouble))
 	      goto unordered;
            rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble, &fpa11->fp_status);
          break;
 
          case typeExtended:
            //printk("extended.\n");
 	   if (floatx80_is_any_nan(fpa11->fpreg[Fm].fExtended))
 	      goto unordered;
            rFm = fpa11->fpreg[Fm].fExtended;
          break;
 
          default: return 0;
       }
    }
 
    if (n_flag)
    {
       rFm.high ^= 0x8000;
    }
 
    return PerformComparisonOperation(rFn,rFm);
 
  unordered:
    /* ?? The FPA data sheet is pretty vague about this, in particular
       about whether the non-E comparisons can ever raise exceptions.
       This implementation is based on a combination of what it says in
       the data sheet, observation of how the Acorn emulator actually
       behaves (and how programs expect it to) and guesswork.  */
    flags |= CC_OVERFLOW;
    flags &= ~(CC_ZERO | CC_NEGATIVE);
 
    if (BIT_AC & readFPSR()) flags |= CC_CARRY;
 
    if (e_flag) float_raise(float_flag_invalid, &fpa11->fp_status);
 
    writeConditionCodes(flags);
    return 1;
 }