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|
/**********************************************************************
* pcopt.c
* Constant Expression Optimizations
*
* Copyright (C) 2008-2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
**********************************************************************/
/**********************************************************************
* Included Files
**********************************************************************/
#include <stdint.h>
#include <stdio.h>
#include "keywords.h"
#include "pdefs.h"
#include "pinsn16.h"
#include "paslib.h"
#include "popt.h"
#include "polocal.h"
#include "pcopt.h"
/**********************************************************************/
int16_t unaryOptimize(void)
{
int16_t nchanges = 0;
register uint16_t temp;
register int16_t i;
TRACE(stderr, "[unaryOptimize]");
/* At least two pcodes are need to perform unary optimizations */
i = 0;
while (i < nops-1)
{
/* Check for a constant value being pushed onto the stack */
if ((pptr[i]->op == oPUSH) || (pptr[i]->op == oPUSHB))
{
/* Turn the oPUSHB into an oPUSH op (temporarily) */
if (pptr[i]->op == oPUSHB)
{
pptr[i]->op = oPUSH;
pptr[i]->arg2 = pptr[i]->arg1;
pptr[i]->arg1 = 0;
} /* end if */
switch (pptr[i+1]->op)
{
/* Delete unary operators on constants */
case oNEG :
pptr[i]->arg2 = -(pptr[i]->arg2);
deletePcode(i+1);
nchanges++;
break;
case oABS :
if (signExtend16(pptr[i]->arg2) < 0)
pptr[i]->arg2 = -signExtend16(pptr[i]->arg2);
deletePcode(i+1);
nchanges++;
break;
case oINC :
(pptr[i]->arg2)++;
deletePcode(i+1);
nchanges++;
break;
case oDEC :
(pptr[i]->arg2)--;
deletePcode(i+1);
nchanges++;
break;
case oNOT :
pptr[i]->arg2 = ~(pptr[i]->arg2);
deletePcode(i+1);
nchanges++;
break;
/* Simplify binary operations on constants */
case oADD :
if (pptr[i]->arg2 == 0)
{
deletePcodePair(i, (i+1));
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i+1]->op = oINC;
deletePcode(i);
nchanges++;
} /* end else if */
else if (pptr[i]->arg2 == (uint16_t)-1)
{
pptr[i+1]->op = oDEC;
deletePcode(i);
nchanges++;
} /* end else if */
else i++;
break;
case oSUB :
if (pptr[i]->arg2 == 0)
{
deletePcodePair(i, (i+1));
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i+1]->op = oDEC;
deletePcode(i);
nchanges++;
} /* end else if */
else if (pptr[i]->arg2 == (uint16_t)-1)
{
pptr[i+1]->op = oINC;
deletePcode(i);
nchanges++;
} /* end else if */
else i++;
break;
case oMUL :
case oDIV :
temp = 0;
switch (pptr[i]->arg2)
{
case 1 :
deletePcodePair(i, (i+1));
nchanges++;
break;
case 16384 : temp++;
case 8192 : temp++;
case 4096 : temp++;
case 2048 : temp++;
case 1024 : temp++;
case 512 : temp++;
case 256 : temp++;
case 128 : temp++;
case 64 : temp++;
case 32 : temp++;
case 16 : temp++;
case 8 : temp++;
case 4 : temp++;
case 2 : temp++;
pptr[i]->arg2 = temp;
if (pptr[i+1]->op == oMUL)
pptr[i+1]->op = oSLL;
else
pptr[i+1]->op = oSRA;
nchanges++;
i++;
break;
default :
i++;
break;
} /* end switch */
break;
case oSLL :
case oSRL :
case oSRA :
case oOR :
if (pptr[i]->arg2 == 0)
{
deletePcodePair(i, (i+1));
nchanges++;
} /* end if */
else i++;
break;
case oAND :
if (pptr[i]->arg2 == 0xffff)
{
deletePcodePair(i, (i+1));
nchanges++;
} /* end if */
else i++;
break;
/* Delete comparisons of constants to zero */
case oEQUZ :
if (pptr[i]->arg2 == 0) pptr[i]->arg2 = -1;
else pptr[i]->arg2 = 0;
deletePcode(i+1);
nchanges++;
break;
case oNEQZ :
if (pptr[i]->arg2 != 0)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcode(i+1);
nchanges++;
break;
case oLTZ :
if (signExtend16(pptr[i]->arg2) < 0)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcode(i+1);
nchanges++;
break;
case oGTEZ :
if (signExtend16(pptr[i]->arg2) >= 0)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcode(i+1);
nchanges++;
break;
case oGTZ :
if (pptr[i]->arg2 > 0) pptr[i]->arg2 = -1;
else pptr[i]->arg2 = 0;
deletePcode(i+1);
nchanges++;
break;
case oLTEZ :
if (pptr[i]->arg2 <= 0) pptr[i]->arg2 = -1;
else pptr[i]->arg2 = 0;
deletePcode(i+1);
nchanges++;
break;
/* Simplify comparisons with certain constants */
case oEQU :
if (pptr[i]->arg2 == 0)
{
pptr[i+1]->op = oEQUZ;
deletePcode(i);
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i]->op = oDEC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oEQUZ;
nchanges++;
} /* end else if */
else if (signExtend16(pptr[i]->arg2) == -1)
{
pptr[i]->op = oINC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oEQUZ;
nchanges++;
} /* end else if */
else i++;
break;
case oNEQ :
if (pptr[i]->arg2 == 0)
{
pptr[i+1]->op = oNEQZ;
deletePcode(i);
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i]->op = oDEC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oNEQZ;
nchanges++;
} /* end else if */
else if (signExtend16(pptr[i]->arg2) == -1)
{
pptr[i]->op = oINC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oNEQZ;
nchanges++;
} /* end else if */
else i++;
break;
case oLT :
if (pptr[i]->arg2 == 0)
{
pptr[i+1]->op = oLTZ;
deletePcode(i);
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i]->op = oDEC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oLTZ;
nchanges++;
} /* end else if */
else if (signExtend16(pptr[i]->arg2) == -1)
{
pptr[i]->op = oINC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oLTZ;
nchanges++;
} /* end else if */
else i++;
break;
case oGTE :
if (pptr[i]->arg2 == 0)
{
pptr[i+1]->op = oGTEZ;
deletePcode(i);
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i]->op = oDEC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oGTEZ;
nchanges++;
} /* end else if */
else if (signExtend16(pptr[i]->arg2) == -1)
{
pptr[i]->op = oINC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oGTEZ;
nchanges++;
} /* end else if */
else i++;
break;
case oGT :
if (pptr[i]->arg2 == 0)
{
pptr[i+1]->op = oGTZ;
deletePcode(i);
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i]->op = oDEC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oGTZ;
nchanges++;
} /* end else if */
else if (signExtend16(pptr[i]->arg2) == -1)
{
pptr[i]->op = oINC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oGTZ;
nchanges++;
} /* end else if */
else i++;
break;
case oLTE :
if (pptr[i]->arg2 == 0)
{
pptr[i+1]->op = oLTEZ;
deletePcode(i);
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i]->op = oDEC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oLTEZ;
nchanges++;
} /* end else if */
else if (signExtend16(pptr[i]->arg2) == -1)
{
pptr[i]->op = oINC;
pptr[i]->arg2 = 0;
pptr[i+1]->op = oLTEZ;
nchanges++;
} /* end else if */
else i++;
break;
/* Simplify or delete condition branches on constants */
case oJEQUZ :
if (pptr[i]->arg2 == 0)
{
pptr[i+1]->op = oJMP;
deletePcode(i);
} /* end if */
else
deletePcodePair(i, (i+1));
nchanges++;
break;
case oJNEQZ :
if (pptr[i]->arg2 != 0)
{
pptr[i+1]->op = oJMP;
deletePcode(i);
} /* end if */
else
deletePcodePair(i, (i+1));
nchanges++;
break;
case oJLTZ :
if (signExtend16(pptr[i]->arg2) < 0)
{
pptr[i+1]->op = oJMP;
deletePcode(i);
} /* end if */
else
deletePcodePair(i, (i+1));
nchanges++;
break;
case oJGTEZ :
if (signExtend16(pptr[i]->arg2) >= 0)
{
pptr[i+1]->op = oJMP;
deletePcode(i);
} /* end if */
else
deletePcodePair(i, (i+1));
nchanges++;
break;
case oJGTZ :
if (pptr[i]->arg2 > 0)
{
pptr[i+1]->op = oJMP;
deletePcode(i);
} /* end if */
else
deletePcodePair(i, (i+1));
nchanges++;
break;
case oJLTEZ :
if (pptr[i]->arg2 <= 0)
{
pptr[i+1]->op = oJMP;
deletePcode(i);
} /* end if */
else
deletePcodePair(i, (i+1));
nchanges++;
break;
default :
i++;
break;
} /* end switch */
/* If the oPUSH instruction is still there, see if we can now */
/* represent it with an oPUSHB instruction */
if ((pptr[i]->op == oPUSH) && (pptr[i]->arg2 < 256))
{
pptr[i]->op = oPUSHB;
pptr[i]->arg1 = pptr[i]->arg2;
pptr[i]->arg2 = 0;
} /* end if */
} /* end if */
/* Delete multiple modifications of DSEG pointer */
else if (pptr[i]->op == oINDS)
{
if (pptr[i+1]->op == oINDS)
{
pptr[i]->arg2 += pptr[i+1]->arg2;
deletePcode(i+1);
} /* end if */
else i++;
} /* end else if */
else i++;
} /* end while */
return (nchanges);
} /* end unaryOptimize */
/**********************************************************************/
int16_t binaryOptimize(void)
{
int16_t nchanges = 0;
register int16_t stmp16;
register int16_t i;
TRACE(stderr, "[binaryOptimize]");
/* At least two pcodes are needed to perform the following binary */
/* operator optimizations */
i = 0;
while (i < nops-2)
{
if ((pptr[i]->op == oPUSH) || (pptr[i]->op == oPUSHB))
{
if ((pptr[i+1]->op == oPUSH) || (pptr[i+1]->op == oPUSHB))
{
/* Turn the oPUSHBs into an oPUSHs op (temporarily) */
if (pptr[i]->op == oPUSHB)
{
pptr[i]->op = oPUSH;
pptr[i]->arg2 = pptr[i]->arg1;
pptr[i]->arg1 = 0;
} /* end if */
if (pptr[i+1]->op == oPUSHB)
{
pptr[i+1]->op = oPUSH;
pptr[i+1]->arg2 = pptr[i+1]->arg1;
pptr[i+1]->arg1 = 0;
} /* end if */
switch (pptr[i+2]->op)
{
case oADD :
pptr[i]->arg2 += pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oSUB :
pptr[i]->arg2 -= pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oMUL :
pptr[i]->arg2 *= pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oDIV :
stmp16 = pptr[i]->arg2 / signExtend16(pptr[i+1]->arg2);
pptr[i]->arg2 = stmp16;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oMOD :
pptr[i]->arg2 %= pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oSLL :
pptr[i]->arg2 <<= pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oSRL :
pptr[i]->arg2 >>= pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oSRA :
stmp16 = (((int16_t)pptr[i]->arg2) >> pptr[i+1]->arg2);
pptr[i]->arg2 = (uint16_t)stmp16;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oOR :
pptr[i]->arg2 |= pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oAND :
pptr[i]->arg2 &= pptr[i+1]->arg2;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oEQU :
if (pptr[i]->arg2 == pptr[i+1]->arg2) pptr[i]->arg2 = -1;
else pptr[i]->arg2 = 0;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oNEQ :
if ((int16_t)pptr[i]->arg2 != (int16_t)pptr[i+1]->arg2)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oLT :
if ((int16_t)pptr[i]->arg2 < (int16_t)pptr[i+1]->arg2)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oGTE :
if ((int16_t)pptr[i]->arg2 >= (int16_t)pptr[i+1]->arg2)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oGT :
if ((int16_t)pptr[i]->arg2 > (int16_t)pptr[i+1]->arg2)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
case oLTE :
if ((int16_t)pptr[i]->arg2 <= (int16_t)pptr[i+1]->arg2)
pptr[i]->arg2 = -1;
else
pptr[i]->arg2 = 0;
deletePcodePair((i+1), (i+2));
nchanges++;
break;
default :
i++;
break;
} /* end switch */
/* If the oPUSH instruction is still there, see if we can now */
/* represent it with an oPUSHB instruction */
if (pptr[i] && (pptr[i]->op == oPUSH) && (pptr[i]->arg2 < 256))
{
pptr[i]->op = oPUSHB;
pptr[i]->arg1 = pptr[i]->arg2;
pptr[i]->arg2 = 0;
} /* end if */
if (pptr[i+1] && (pptr[i+1]->op == oPUSH) && (pptr[i+1]->arg2 < 256))
{
pptr[i+1]->op = oPUSHB;
pptr[i+1]->arg1 = pptr[i+1]->arg2;
pptr[i+1]->arg2 = 0;
} /* end if */
} /* end if */
/* A single (constant) pcode is sufficient to perform the */
/* following binary operator optimizations */
else if ((pptr[i+1]->op == oLDSH) || (pptr[i+1]->op == oLDSB) ||
(pptr[i+1]->op == oLAS) || (pptr[i+1]->op == oLAC))
{
/* Turn the oPUSHB into a oPUSH op (temporarily) */
if (pptr[i]->op == oPUSHB)
{
pptr[i]->op = oPUSH;
pptr[i]->arg2 = pptr[i]->arg1;
pptr[i]->arg1 = 0;
} /* end if */
switch (pptr[i+2]->op)
{
case oADD :
if (pptr[i]->arg2 == 0)
{
deletePcodePair(i, (i+2));
nchanges++;
} /* end if */
else if (pptr[i]->arg2 == 1)
{
pptr[i+2]->op = oINC;
deletePcode(i);
nchanges++;
} /* end else if */
else if (pptr[i]->arg2 == (uint16_t)-1)
{
pptr[i+2]->op = oDEC;
deletePcode(i);
nchanges++;
} /* end else if */
else i++;
break;
case oSUB :
if (pptr[i]->arg2 == 0)
{
pptr[i]->op = oNEG;
deletePcode(i);
nchanges++;
} /* end if */
else i++;
break;
case oMUL :
stmp16 = 0;
switch (pptr[i]->arg2)
{
case 1 :
deletePcodePair(i, (i+2));
nchanges++;
break;
case 16384 : stmp16++;
case 8192 : stmp16++;
case 4096 : stmp16++;
case 2048 : stmp16++;
case 1024 : stmp16++;
case 512 : stmp16++;
case 256 : stmp16++;
case 128 : stmp16++;
case 64 : stmp16++;
case 32 : stmp16++;
case 16 : stmp16++;
case 8 : stmp16++;
case 4 : stmp16++;
case 2 : stmp16++;
pptr[i]->op = pptr[i+1]->op;
pptr[i]->arg1 = pptr[i+1]->arg1;
pptr[i]->arg2 = pptr[i+1]->arg2;
pptr[i+1]->op = oPUSH;
pptr[i+1]->arg1 = 0;
pptr[i+1]->arg2 = stmp16;
pptr[i+2]->op = oSLL;
nchanges++;
i++;
break;
default :
i++;
break;
} /* end switch */
break;
case oOR :
if (pptr[i]->arg2 == 0)
{
deletePcodePair(i, (i+2));
nchanges++;
} /* end if */
else i++;
break;
case oAND :
if (pptr[i]->arg2 == 0xffff)
{
deletePcodePair(i, (i+2));
nchanges++;
} /* end if */
else i++;
break;
case oEQU :
if (pptr[i]->arg2 == 0)
{
pptr[i+2]->op = oEQUZ;
deletePcode(i);
nchanges++;
} /* end if */
else i++;
break;
case oNEQ :
if (pptr[i]->arg2 == 0)
{
pptr[i+2]->op = oNEQZ;
deletePcode(i);
nchanges++;
} /* end if */
else i++;
break;
case oLT :
if (pptr[i]->arg2 == 0)
{
pptr[i+2]->op = oGTEZ;
deletePcode(i);
nchanges++;
} /* end if */
else i++;
break;
case oGTE :
if (pptr[i]->arg2 == 0)
{
pptr[i+2]->op = oLTZ;
deletePcode(i);
nchanges++;
} /* end if */
else i++;
break;
case oGT :
if (pptr[i]->arg2 == 0)
{
pptr[i+2]->op = oLTEZ;
deletePcode(i);
nchanges++;
} /* end if */
else i++;
break;
case oLTE :
if (pptr[i]->arg2 == 0)
{
pptr[i+2]->op = oGTZ;
deletePcode(i);
nchanges++;
} /* end if */
else i++;
break;
default :
i++;
break;
} /* end switch */
/* If the oPUSH instruction is still there, see if we can now */
/* represent it with an oPUSHB instruction */
if ((pptr[i]->op == oPUSH) && (pptr[i]->arg2 < 256))
{
pptr[i]->op = oPUSHB;
pptr[i]->arg1 = pptr[i]->arg2;
pptr[i]->arg2 = 0;
} /* end if */
} /* end else if */
else i++;
} /* end if */
/* Misc improvements on binary operators */
else if (pptr[i]->op == oNEG)
{
/* Negation followed by add is subtraction */
if (pptr[i+1]->op == oADD)
{
pptr[i+1]->op = oSUB;
deletePcode(i);
nchanges++;
}
/* Negation followed by subtraction is addition */
else if (pptr[i]->op == oSUB)
{
pptr[i+1]->op = oADD;
deletePcode(i);
nchanges++;
}
else i++;
}
else i++;
} /* end while */
return (nchanges);
} /* end binaryOptimize */
/**********************************************************************/
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