118 lines
3.5 KiB
C
118 lines
3.5 KiB
C
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/*
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NetWinder Floating Point Emulator
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(c) Rebel.COM, 1998,1999
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Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "fpa11.h"
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#include "fpopcode.h"
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unsigned int SingleCPDO(const unsigned int opcode);
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unsigned int DoubleCPDO(const unsigned int opcode);
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unsigned int ExtendedCPDO(const unsigned int opcode);
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unsigned int EmulateCPDO(const unsigned int opcode)
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{
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FPA11 *fpa11 = GET_FPA11();
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unsigned int Fd, nType, nDest, nRc = 1;
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//printk("EmulateCPDO(0x%08x)\n",opcode);
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/* Get the destination size. If not valid let Linux perform
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an invalid instruction trap. */
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nDest = getDestinationSize(opcode);
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if (typeNone == nDest) return 0;
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SetRoundingMode(opcode);
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/* Compare the size of the operands in Fn and Fm.
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Choose the largest size and perform operations in that size,
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in order to make use of all the precision of the operands.
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If Fm is a constant, we just grab a constant of a size
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matching the size of the operand in Fn. */
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if (MONADIC_INSTRUCTION(opcode))
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nType = nDest;
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else
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nType = fpa11->fType[getFn(opcode)];
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if (!CONSTANT_FM(opcode))
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{
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register unsigned int Fm = getFm(opcode);
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if (nType < fpa11->fType[Fm])
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{
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nType = fpa11->fType[Fm];
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}
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}
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switch (nType)
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{
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case typeSingle : nRc = SingleCPDO(opcode); break;
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case typeDouble : nRc = DoubleCPDO(opcode); break;
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case typeExtended : nRc = ExtendedCPDO(opcode); break;
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default : nRc = 0;
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}
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/* If the operation succeeded, check to see if the result in the
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destination register is the correct size. If not force it
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to be. */
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Fd = getFd(opcode);
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nType = fpa11->fType[Fd];
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if ((0 != nRc) && (nDest != nType))
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{
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switch (nDest)
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{
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case typeSingle:
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{
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if (typeDouble == nType)
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fpa11->fpreg[Fd].fSingle =
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float64_to_float32(fpa11->fpreg[Fd].fDouble);
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else
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fpa11->fpreg[Fd].fSingle =
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floatx80_to_float32(fpa11->fpreg[Fd].fExtended);
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}
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break;
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case typeDouble:
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{
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if (typeSingle == nType)
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fpa11->fpreg[Fd].fDouble =
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float32_to_float64(fpa11->fpreg[Fd].fSingle);
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else
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fpa11->fpreg[Fd].fDouble =
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floatx80_to_float64(fpa11->fpreg[Fd].fExtended);
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}
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break;
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case typeExtended:
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{
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if (typeSingle == nType)
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fpa11->fpreg[Fd].fExtended =
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float32_to_floatx80(fpa11->fpreg[Fd].fSingle);
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else
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fpa11->fpreg[Fd].fExtended =
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float64_to_floatx80(fpa11->fpreg[Fd].fDouble);
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}
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break;
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}
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fpa11->fType[Fd] = nDest;
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}
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return nRc;
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}
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