diff options
author | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2009-12-18 15:43:29 +0000 |
---|---|---|
committer | patacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3> | 2009-12-18 15:43:29 +0000 |
commit | eb3074a4fe3b7c86d2a3ca139eb881964f2f23e1 (patch) | |
tree | 5ce1e76df21acb8d0b5b209fe7f2461a78c36a8e /misc/pascal/insn16/popt/pcopt.c | |
parent | af6cfa901fa8cc78607976e8ed8aedc195500aff (diff) | |
download | nuttx-eb3074a4fe3b7c86d2a3ca139eb881964f2f23e1.tar.gz nuttx-eb3074a4fe3b7c86d2a3ca139eb881964f2f23e1.tar.bz2 nuttx-eb3074a4fe3b7c86d2a3ca139eb881964f2f23e1.zip |
Update to use stdint/stdbool.h
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@2383 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'misc/pascal/insn16/popt/pcopt.c')
-rw-r--r-- | misc/pascal/insn16/popt/pcopt.c | 1811 |
1 files changed, 906 insertions, 905 deletions
diff --git a/misc/pascal/insn16/popt/pcopt.c b/misc/pascal/insn16/popt/pcopt.c index 5af19002c..5f8deed80 100644 --- a/misc/pascal/insn16/popt/pcopt.c +++ b/misc/pascal/insn16/popt/pcopt.c @@ -1,905 +1,906 @@ -/**********************************************************************
- * pcopt.c
- * Constant Expression Optimizations
- *
- * Copyright (C) 2008 Gregory Nutt. All rights reserved.
- * Author: Gregory Nutt <spudmonkey@racsa.co.cr>
- *
- * 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 <stdio.h>
-
-#include "keywords.h"
-#include "pdefs.h"
-#include "pinsn16.h"
-
-#include "paslib.h"
-#include "popt.h"
-#include "polocal.h"
-#include "pcopt.h"
-
-/**********************************************************************/
-
-sint16 unaryOptimize(void)
-{
- sint16 nchanges = 0;
- register uint16 temp;
- register sint16 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)-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)-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 */
-
-/**********************************************************************/
-
-sint16 binaryOptimize(void)
-{
- sint16 nchanges = 0;
- register sint16 stmp16;
- register sint16 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 = (((sint16)pptr[i]->arg2) >> pptr[i+1]->arg2);
- pptr[i]->arg2 = (uint16)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 ((sint16)pptr[i]->arg2 != (sint16)pptr[i+1]->arg2)
- pptr[i]->arg2 = -1;
- else
- pptr[i]->arg2 = 0;
- deletePcodePair((i+1), (i+2));
- nchanges++;
- break;
-
- case oLT :
- if ((sint16)pptr[i]->arg2 < (sint16)pptr[i+1]->arg2)
- pptr[i]->arg2 = -1;
- else
- pptr[i]->arg2 = 0;
- deletePcodePair((i+1), (i+2));
- nchanges++;
- break;
-
- case oGTE :
- if ((sint16)pptr[i]->arg2 >= (sint16)pptr[i+1]->arg2)
- pptr[i]->arg2 = -1;
- else
- pptr[i]->arg2 = 0;
- deletePcodePair((i+1), (i+2));
- nchanges++;
- break;
-
- case oGT :
- if ((sint16)pptr[i]->arg2 > (sint16)pptr[i+1]->arg2)
- pptr[i]->arg2 = -1;
- else
- pptr[i]->arg2 = 0;
- deletePcodePair((i+1), (i+2));
- nchanges++;
- break;
-
- case oLTE :
- if ((sint16)pptr[i]->arg2 <= (sint16)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)-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 */
-
-/**********************************************************************/
-
+/********************************************************************** + * pcopt.c + * Constant Expression Optimizations + * + * Copyright (C) 2008-2009 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <spudmonkey@racsa.co.cr> + * + * 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 */ + +/**********************************************************************/ + |