From: MaartenBrock <MaartenBrock@4a8a32a2-be11-0410-ad9d-d568d2c75423>
Date: Sun, 25 Feb 2007 21:43:00 +0000 (+0000)
Subject: * src/mcs51/rtrack.c,
X-Git-Url: https://git.gag.com/?a=commitdiff_plain;h=57c133d2e24db717fc72275a7de171c2b1b1d956;p=fw%2Fsdcc

* src/mcs51/rtrack.c,
* src/mcs51/rtrack.h: set svn properties


git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@4653 4a8a32a2-be11-0410-ad9d-d568d2c75423
---

diff --git a/src/mcs51/rtrack.c b/src/mcs51/rtrack.c
index 6fbc92b7..0c64d07f 100644
--- a/src/mcs51/rtrack.c
+++ b/src/mcs51/rtrack.c
@@ -1,684 +1,684 @@
-/*-------------------------------------------------------------------------
-  rtrack.c - tracking content of registers on an mcs51
-
-  Copyright 2007 Frieder Ferlemann (Frieder Ferlemann AT web.de)
-
-  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, write to the Free Software
-  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
--------------------------------------------------------------------------*/
-
-/*-------------------------------------------------------------------------
-  Status:
-    - passes regression test suite, still bugs are likely
-    - only active if environment variable SDCC_RTRACK is set
-
-  Missed opportunities:
-    - does not track symbols as in "mov a,#_my_int" or "mov a,#(_my_int+1)"
-    - only used with moves to acc so chances to use: "inc dptr",
-      "inc r2", "add a,r2" or "mov r2,a" would not be detected)
-    - a label causes loss of tracking (no handling of information of blocks
-      known to follow/preceed the current block)
-    - not used in aopGet or genRet
--------------------------------------------------------------------------*/
-
-
-#include <stdio.h>
-#include <string.h>
-#include "SDCCglobl.h"
-
-#include "common.h"
-#include "ralloc.h"
-#include "gen.h"
-
-#define DEBUG(x)
-//#define DEBUG(x) x
-
-#define D(x) x
-
-#define REGS8051_SET(idx,val) do{ \
-                                  regs8051[idx].value = (val) & 0xff; \
-                                  regs8051[idx].valueKnown = 1; \
-                                  DEBUG(printf("%s:0x%02x\n",regs8051[idx].name, \
-                                                       regs8051[idx].value);) \
-                              } while(0)
-
-#define REGS8051_UNSET(idx)   do{ \
-                                  regs8051[idx].valueKnown = 0; \
-                                  DEBUG(printf("%s:*\n",regs8051[idx].name);) \
-                              } while(0)
-
-/* r0..r7 are not in numerical order in struct regs: r2..r7,r0,r1 */
-#define Rx_NUM_TO_IDX(num) (R2_IDX+((num-2)&0x07))
-
-
-/* move this (or rtrackGetLit() and rtrackMoveALit()
-   elsewhere? stealing emitcode from gen.c */
-void emitcode (const char *inst, const char *fmt,...);
-
-
-static int enable = -1;
-
-/*
-static void dumpAll()
-{
-  unsigned int i;
-  unsigned int nl=0;
-
-  for (i=0; i<END_IDX; i++)
-    {
-       if (regs8051[i].valueKnown)
-         {
-           if (!nl)
-             {
-               DEBUG(printf("know:");)
-             }
-           DEBUG(printf(" %s:0x%02x",regs8051[i].name,regs8051[i].value);)
-           nl = 1;
-         }
-    }
-  if (nl)
-    {
-      DEBUG(printf("\n");)
-    }
-}
-*/
-
-
-static void invalidateAllRx()
-{
-  //DEBUG(dumpAll();)
-  DEBUG(printf("R0..7:*\n");)
-  regs8051[R2_IDX].valueKnown = 0;
-  regs8051[R3_IDX].valueKnown = 0;
-  regs8051[R4_IDX].valueKnown = 0;
-  regs8051[R5_IDX].valueKnown = 0;
-  regs8051[R6_IDX].valueKnown = 0;
-  regs8051[R7_IDX].valueKnown = 0;
-  regs8051[R0_IDX].valueKnown = 0;
-  regs8051[R1_IDX].valueKnown = 0;
-}
-
-static void invalidateAll()
-{
-  DEBUG(printf("All:* ");)
-  invalidateAllRx();
-  regs8051[DPL_IDX].valueKnown = 0;
-  regs8051[DPH_IDX].valueKnown = 0;
-  regs8051[B_IDX].valueKnown = 0;
-  regs8051[A_IDX].valueKnown = 0;
-}
-
-static regs * getReg(const char *str)
-{
-  char *s;
-  int regNum;
-
-  regNum = strtol (str, &s, 16);
-  if (s == str+1)
-    {
-      return &regs8051[Rx_NUM_TO_IDX(regNum)];
-    }
-  return NULL;
-}
-
-/* tracking values within registers by looking
-   at the line passed to the assembler.
-   Tries to keep regs8051[] up to date */
-void rtrackUpdate (const char *line)
-{
-  if (enable == -1)
-    enable = (NULL != getenv("SDCC_RTRACK"));
-
-  if (!enable ||
-      *line == ';' ||                 /* comment */
-      (NULL != strstr( line, "==."))) /* dirty check for _G.debugLine */
-    return;                           /* nothing to do */
-
-  DEBUG(printf("%s\n",line);)
-
-  if (!strncmp (line,"mov",3))
-    {
-      /* check literal mov to accumulator */
-      if(!strncmp (line,"mov\ta,#0x",9))
-        {
-          char *s;
-          int value;
-
-          value = strtol (line+7, &s, 16);
-          if (s != line+7)
-              REGS8051_SET (A_IDX, value); /* valid hex found */
-          else
-              REGS8051_UNSET (A_IDX); /* probably a symbol (not handled) */
-
-          return;
-        }
-
-      if (!strncmp (line,"mov\ta,r",7))
-        {
-          /* handle mov from Rx if Rx is known */
-          regs *r = getReg(line+7);
-          if (r && r->valueKnown)
-            {
-              REGS8051_SET (A_IDX, r->value);
-              return;
-            }
-          REGS8051_UNSET (A_IDX);
-          return;
-        }
-
-      if (!strncmp (line,"mov\ta",5))
-        {
-          REGS8051_UNSET (A_IDX);
-          return;
-        }
-
-      if (!strncmp (line,"movc\ta",6) ||
-          !strncmp (line,"movx\ta",6))
-        {
-          REGS8051_UNSET (A_IDX);
-          return;
-        }
-
-      /* move direct to symbol, do not care */
-      if (!strncmp (line,"mov\t_",5) ||
-          !strncmp (line,"mov\t(_",6))
-        return;
-
-      /* check literal mov to register */
-      if (!strncmp (line,"mov\tr",5))
-        {
-          char *s;
-          int value;
-          int regNum;
-
-          regNum = strtol (line+5, &s, 16);
-          if (s == line+6)
-            {
-              value = strtol (line+8, &s, 16);
-              if ((s != line+8) && !strncmp (line+6,",#0x",4))
-                REGS8051_SET (Rx_NUM_TO_IDX(regNum), value);
-              else
-                REGS8051_UNSET (Rx_NUM_TO_IDX(regNum));
-              return;
-            }
-        }
-
-      /* mov to psw can change register bank */
-      if (!strncmp (line,"mov\tpsw,",8))
-        {
-          invalidateAllRx();
-          return;
-        }
-
-      /* no tracking of these, so we do not care */
-      if (!strncmp (line,"mov\tdptr,#",10) ||
-          !strncmp (line,"mov\tdpl,",8) ||
-          !strncmp (line,"mov\tdph,",8) ||
-          !strncmp (line,"mov\tsp,",7) ||
-          !strncmp (line,"mov\tb,",6))
-        return;
-
-      /* mov to xdata memory does not change registers */
-      if (!strncmp (line,"movx\t@",6))
-        return;
-
-      if (!strncmp (line,"mov\t@",5))
-        {
-          invalidateAllRx();
-          return;
-        }
-    }
-
-  /* no tracking of SP */
-  if (!strncmp (line,"push",4))
-    return;
-
-  if (!strncmp (line,"pop\ta",5))
-    {
-      if (!strncmp (line+4,"acc",3)){ REGS8051_UNSET (A_IDX); return; }
-      if (!strncmp (line+4,"ar2",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (2)); return; }
-      if (!strncmp (line+4,"ar3",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (3)); return; }
-      if (!strncmp (line+4,"ar4",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (4)); return; }
-      if (!strncmp (line+4,"ar5",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (5)); return; }
-      if (!strncmp (line+4,"ar6",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (6)); return; }
-      if (!strncmp (line+4,"ar7",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (7)); return; }
-      if (!strncmp (line+4,"ar0",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (0)); return; }
-      if (!strncmp (line+4,"ar1",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (1)); return; }
-    }
-
-  if (!strncmp (line,"inc",3))
-    {
-      /* no tracking of dptr, ignore */
-      if (!strcmp (line,"inc\tdptr") ||
-          !strcmp (line,"inc\tdph") ||
-          !strcmp (line,"inc\tdpl"))
-        return;
-
-      if (!strcmp (line,"inc\ta"))
-        {
-          if (regs8051[A_IDX].valueKnown)
-            REGS8051_SET (A_IDX, regs8051[A_IDX].value+1);
-          return;
-        }
-
-      if(!strncmp (line,"inc\tr",5))
-        {
-          regs *r = getReg(line+5);
-          if (r && r->valueKnown)
-            {
-              REGS8051_SET (r->rIdx, r->value+1);
-            }
-          return;
-        }
-    }
-
-  /* some bit in acc is cleared
-     MB: I'm too lazy to find out which right now */
-  if (!strncmp (line,"jbc\tacc",7))
-    {
-      REGS8051_UNSET (A_IDX);
-      return;
-    }
-
-  /* unfortunately the label typically following these
-     will cause loss of tracking */
-  if (!strncmp (line,"jc\t",3) ||
-      !strncmp (line,"jnc\t",4) ||
-      !strncmp (line,"jb\t",3) ||
-      !strncmp (line,"jnb\t",4) ||
-      !strncmp (line,"jbc\t",4))
-    return;
-
-  /* if branch not taken in "cjne r2,#0x08,somewhere" 
-     r2 is known to be 8 */
-  if (!strncmp (line,"cjne",4))
-    {
-      if(!strncmp (line,"cjne\ta,#0x",10))
-        {
-          char *s;
-          int value;
-
-          value = strtol (line+8, &s, 16);
-          if (s != line+8)
-              REGS8051_SET (A_IDX, value); /* valid hex found */
-        }
-      if(!strncmp (line,"cjne\tr",6))
-        {
-          char *s;
-          int value;
-          regs *r = getReg(line+6);
-          value = strtol (line+8, &s, 16);
-          if (r && s != line+8)
-              REGS8051_SET (r->rIdx, value); /* valid hex found */
-        }
-      return;
-    }
-
-  /* acc eventually known to be zero */
-  if (!strncmp (line,"jz\t",3))
-    return;
-
-  /* acc eventually known to be zero */
-  if (!strncmp (line,"jnz\t",4))
-    {
-      REGS8051_SET (A_IDX, 0x00); // branch not taken
-      return;
-    }
-
-  if (!strncmp (line,"djnz\tr",6))
-    {
-      char *s;
-      int regNum;
-
-      regNum = strtol (line+6, &s, 16);
-      if (s == line+7)
-        {
-          //REGS8051_UNSET (Rx_NUM_TO_IDX(regNum));
-          REGS8051_SET (Rx_NUM_TO_IDX(regNum), 0x00); // branch not taken
-          return;
-        }
-    }
-
-  /* only carry bit, so we do not care */
-  if (!strncmp (line,"setb\tc",6) ||
-      !strncmp (line,"clr\tc",5) ||
-      !strncmp (line,"cpl\tc",5))
-    return;
-
-  if (!strncmp (line,"add\ta,",6) ||
-      !strncmp (line,"addc\ta,",7)||
-      !strncmp (line,"subb\ta,",7)||
-      !strncmp (line,"xrl\ta,",6) ||
-      !strncmp (line,"orl\ta,",6) ||
-      !strncmp (line,"anl\ta,",6) ||
-      !strncmp (line,"da\ta",4)   ||
-      !strncmp (line,"rlc\ta,",6) ||
-      !strncmp (line,"rrc\ta,",6) ||
-      !strncmp (line,"setb\ta",6) ||
-      !strncmp (line,"clrb\ta,",7)||
-      !strncmp (line,"cpl\tacc",7))
-    {
-      /* could also handle f.e. "add a,Rx" if a, Rx are known or "xrl a,#0x08" */
-      REGS8051_UNSET (A_IDX);
-      return;
-    }
-
-
-  if (!strncmp (line,"dec",3))
-    {
-      /* no tracking of dptr, so we would not care */
-      if (!strcmp (line,"dec\tdph") ||
-          !strcmp (line,"dec\tdpl"))
-        return;
-
-      if (!strcmp (line,"dec\ta"))
-        {
-          if (regs8051[A_IDX].valueKnown)
-            REGS8051_SET (A_IDX, regs8051[A_IDX].value-1);
-          return;
-        }
-
-      if(!strncmp (line,"dec\tr",5))
-        {
-          regs *r = getReg(line+5);
-          if (r && r->valueKnown)
-            {
-              REGS8051_SET (r->rIdx, r->value-1);
-            }
-          return;
-        }
-    }
-
-
-  if (!strcmp (line,"clr\ta"))
-    {
-      REGS8051_SET (A_IDX, 0);
-      return;
-    }
-
-  if (!strcmp (line,"cpl\ta"))
-    {
-      if (regs8051[A_IDX].valueKnown)
-        REGS8051_SET (A_IDX, ~regs8051[A_IDX].value);
-      return;
-    }
-  if (!strcmp (line,"rl\ta"))
-    {
-      if (regs8051[A_IDX].valueKnown)
-        REGS8051_SET (A_IDX, (regs8051[A_IDX].value<<1) | 
-                             (regs8051[A_IDX].value>>7) );
-      return;
-    }
-  if (!strcmp (line,"rr\ta"))
-    {
-      if (regs8051[A_IDX].valueKnown)
-        REGS8051_SET (A_IDX, (regs8051[A_IDX].value>>1) |
-                             (regs8051[A_IDX].value<<7));
-      return;
-    }
-  if (!strcmp (line,"swap\ta"))
-    {
-      if (regs8051[A_IDX].valueKnown)
-        REGS8051_SET (A_IDX, (regs8051[A_IDX].value>>4) |
-                             (regs8051[A_IDX].value<<4));
-      return;
-    }
-
-  if (!strncmp (line,"mul",3) ||
-      !strncmp (line,"div",3)
-      )
-    {
-      REGS8051_UNSET (A_IDX);
-      REGS8051_UNSET (B_IDX);
-      return;
-    }
-
-  /* assuming these library functions have no side-effects */
-  if (!strcmp (line,"lcall"))
-    {
-      if (!strcmp (line,"lcall\t__gptrput"))
-        {
-          /* invalidate R0..R7 because they might have been changed */
-          /* MB: too paranoid ? */
-          //invalidateAllRx();
-          return;
-        }
-      if (!strcmp (line,"lcall\t__gptrget"))
-        {
-          REGS8051_UNSET (A_IDX);
-          return;
-        }
-      if (!strcmp (line,"lcall\t__decdptr"))
-        {
-          return;
-        }
-     }
-
-  if (!strncmp (line,"xch\ta,r",7))
-    {
-      /* handle xch acc with Rn */
-      regs *r = getReg(line+7);
-      if (r)
-        {
-          unsigned swap;
-          swap = r->valueKnown;
-          r->valueKnown = regs8051[A_IDX].valueKnown;
-          regs8051[A_IDX].valueKnown = swap;
-
-          swap = r->value;
-          r->value = regs8051[A_IDX].value;
-          regs8051[A_IDX].value = swap;
-          return;
-        }
-    }
-
-  /* all others unrecognized, invalidate */
-  invalidateAll();
-}
-
-
-/* expects f.e. "#0x01" and returns either "#0x01"
-   if the value is not known to be within registers
-   or "a" or "r0".."r7".
-   (mov a,r7 or add a,r7 need one byte whereas
-    mov a,#0x01 or add a,#0x01 would take two
- */
-char * rtrackGetLit(const char *x)
-{
-  unsigned int i;
-
-  char *s;
-
-  if (enable != 1)
-    return (char *)x;
-
-  /* was it a numerical literal? */
-  if (*x == '#')
-    {
-      int val = strtol (x+1, &s, 16);
-      if (x+1 != s)
-        {
-          /* try to get from acc */
-          regs *r = &regs8051[A_IDX];
-          if (r->valueKnown &&
-              r->value == val)
-            {
-              D(emitcode (";", "genFromRTrack 0x%02x=%s", val, r->name));
-              return r->name;
-            }
-          /* try to get from register R0..R7 */
-          for (i=0; i<8; i++)
-            {
-              regs *r = &regs8051[Rx_NUM_TO_IDX(i)];
-              if (r->valueKnown &&
-                  r->value == val)
-                {
-                  D(emitcode (";", "genFromRTrack 0x%02x=%s", val, r->name));
-                  return r->name;
-                }
-            }
-        }
-      else
-        {
-          /* probably a symbolic literal as in "mov r3,#(_i+1)",
-             not handled... */
-        }
-    }
-
-  return (char *)x;
-}
-
-/* Similar to the above function 
-   As the destination is the accumulator try harder yet and
-   try to generate the result with arithmetic operations */
-int rtrackMoveALit (const char *x)
-{
-
-  if (enable != 1)
-    return 0;
-
-  /* if it is a literal mov try to get it cheaper */
-  if ( *x == '#' )
-    {
-      regs *a = &regs8051[A_IDX];
-
-      char *s;
-      int val = strtol (x+1, &s, 16);
-
-      /* was it a numerical literal? */
-      if (x+1 != s)
-        {
-          /* prefer mov a,#0x00 */
-          if (val == 0 &&
-              ((a->valueKnown && a->value != 0) ||
-               !a->valueKnown))
-            {
-              /* peepholes convert to clr a */
-              /* MB: why not here ? */
-              emitcode ("mov", "a,#0x00");
-              return 1;
-            }
-
-          if (a->valueKnown)
-            {
-              /* already there? */
-              if (val == a->value)
-                {
-                  D(emitcode (";", "genFromRTrack acc=0x%02x", a->value));
-                  return 1;
-                }
-
-              /* can be calculated with an instruction
-                 that does not change flags from acc itself? */
-              if (val == ((a->value+1) & 0xff) )
-                {
-                  D(emitcode (";", "genFromRTrack 0x%02x=0x%02x+1", val, a->value));
-                  emitcode ("inc", "a");
-                  return 1;
-                }
-              if (val == ((a->value-1) & 0xff) )
-                {
-                  D(emitcode (";", "genFromRTrack 0x%02x=0x%02x-1", val, a->value));
-                  emitcode ("dec", "a");
-                  return 1;
-                }
-              if (val == ((~a->value) & 0xff) )
-                {
-                  D(emitcode (";", "genFromRTrack 0x%02x=~0x%02x", val, a->value));
-                  emitcode ("cpl", "a");
-                  return 1;
-                }
-              if (val == (((a->value>>1) |
-                           (a->value<<7)) & 0xff))
-                {
-                  D(emitcode (";", "genFromRTrack 0x%02x=rr(0x%02x)", val, a->value));
-                  emitcode ("rr", "a");
-                  return 1;
-                }
-              if (val == (((a->value<<1) |
-                           (a->value>>7)) & 0xff ))
-                {
-                  D(emitcode (";", "genFromRTrack 0x%02x=rl(0x%02x)", val, a->value));
-                  emitcode ("rl", "a");
-                  return 1;
-                }
-              if (val == ( ((a->value & 0x0f)<<4) |
-                           ((a->value & 0xf0)>>4) ))
-                {
-                  D(emitcode (";", "genFromRTrack 0x%02x=swap(0x%02x)", val, a->value));
-                  emitcode ("swap", "a");
-                  return 1;
-                }
-              /* Decimal Adjust Accumulator (da a) changes flags so not used */
-            }
-
-
-          {
-            unsigned int i;
-            char *ptr= rtrackGetLit(x);
-
-            if (x != ptr)
-              {
-                /* could get from register, fine */
-                emitcode ("mov", "a,%s", ptr);
-                return 1;
-              }
-
-            /* not yet giving up - try to calculate from register R0..R7 */
-            for (i=0; i<8; i++)
-              {
-                regs *r = &regs8051[Rx_NUM_TO_IDX(i)];
-
-                if (a->valueKnown && r->valueKnown)
-                  {
-                    /* calculate with a single byte instruction from R0..R7? */
-                    if (val == (a->value | r->value))
-                      {
-                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x|0x%02x",
-                                    val, a->value, r->value));
-                        emitcode ("orl", "a,%s",r->name);
-                        return 1;
-                      }
-                    if (val == (a->value & r->value))
-                      {
-                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x&0x%02x",
-                                    val, a->value, r->value));
-                        emitcode ("anl", "a,%s", r->name);
-                        return 1;
-                      }
-                    if (val == (a->value ^ r->value))
-                      {
-                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x^0x%02x",
-                                    val, a->value, r->value));
-                        emitcode ("xrl", "a,%s", r->name);
-                        return 1;
-                      }
-                    /* changes flags (does that matter?)
-                    if (val == (a->value + r->value))
-                      {
-                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x+%0x02x",
-                                    val, a->value, r->value));
-                        emitcode ("add", "a,%s",r->name);
-                        return 1;
-                      }
-                    so not used */
-                  }
-              }
-          }
-      }
-    }
-
-  return 0;
-}
-
+/*-------------------------------------------------------------------------
+  rtrack.c - tracking content of registers on an mcs51
+
+  Copyright 2007 Frieder Ferlemann (Frieder Ferlemann AT web.de)
+
+  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, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+-------------------------------------------------------------------------*/
+
+/*-------------------------------------------------------------------------
+  Status:
+    - passes regression test suite, still bugs are likely
+    - only active if environment variable SDCC_RTRACK is set
+
+  Missed opportunities:
+    - does not track symbols as in "mov a,#_my_int" or "mov a,#(_my_int+1)"
+    - only used with moves to acc so chances to use: "inc dptr",
+      "inc r2", "add a,r2" or "mov r2,a" would not be detected)
+    - a label causes loss of tracking (no handling of information of blocks
+      known to follow/preceed the current block)
+    - not used in aopGet or genRet
+-------------------------------------------------------------------------*/
+
+
+#include <stdio.h>
+#include <string.h>
+#include "SDCCglobl.h"
+
+#include "common.h"
+#include "ralloc.h"
+#include "gen.h"
+
+#define DEBUG(x)
+//#define DEBUG(x) x
+
+#define D(x) x
+
+#define REGS8051_SET(idx,val) do{ \
+                                  regs8051[idx].value = (val) & 0xff; \
+                                  regs8051[idx].valueKnown = 1; \
+                                  DEBUG(printf("%s:0x%02x\n",regs8051[idx].name, \
+                                                       regs8051[idx].value);) \
+                              } while(0)
+
+#define REGS8051_UNSET(idx)   do{ \
+                                  regs8051[idx].valueKnown = 0; \
+                                  DEBUG(printf("%s:*\n",regs8051[idx].name);) \
+                              } while(0)
+
+/* r0..r7 are not in numerical order in struct regs: r2..r7,r0,r1 */
+#define Rx_NUM_TO_IDX(num) (R2_IDX+((num-2)&0x07))
+
+
+/* move this (or rtrackGetLit() and rtrackMoveALit()
+   elsewhere? stealing emitcode from gen.c */
+void emitcode (const char *inst, const char *fmt,...);
+
+
+static int enable = -1;
+
+/*
+static void dumpAll()
+{
+  unsigned int i;
+  unsigned int nl=0;
+
+  for (i=0; i<END_IDX; i++)
+    {
+       if (regs8051[i].valueKnown)
+         {
+           if (!nl)
+             {
+               DEBUG(printf("know:");)
+             }
+           DEBUG(printf(" %s:0x%02x",regs8051[i].name,regs8051[i].value);)
+           nl = 1;
+         }
+    }
+  if (nl)
+    {
+      DEBUG(printf("\n");)
+    }
+}
+*/
+
+
+static void invalidateAllRx()
+{
+  //DEBUG(dumpAll();)
+  DEBUG(printf("R0..7:*\n");)
+  regs8051[R2_IDX].valueKnown = 0;
+  regs8051[R3_IDX].valueKnown = 0;
+  regs8051[R4_IDX].valueKnown = 0;
+  regs8051[R5_IDX].valueKnown = 0;
+  regs8051[R6_IDX].valueKnown = 0;
+  regs8051[R7_IDX].valueKnown = 0;
+  regs8051[R0_IDX].valueKnown = 0;
+  regs8051[R1_IDX].valueKnown = 0;
+}
+
+static void invalidateAll()
+{
+  DEBUG(printf("All:* ");)
+  invalidateAllRx();
+  regs8051[DPL_IDX].valueKnown = 0;
+  regs8051[DPH_IDX].valueKnown = 0;
+  regs8051[B_IDX].valueKnown = 0;
+  regs8051[A_IDX].valueKnown = 0;
+}
+
+static regs * getReg(const char *str)
+{
+  char *s;
+  int regNum;
+
+  regNum = strtol (str, &s, 16);
+  if (s == str+1)
+    {
+      return &regs8051[Rx_NUM_TO_IDX(regNum)];
+    }
+  return NULL;
+}
+
+/* tracking values within registers by looking
+   at the line passed to the assembler.
+   Tries to keep regs8051[] up to date */
+void rtrackUpdate (const char *line)
+{
+  if (enable == -1)
+    enable = (NULL != getenv("SDCC_RTRACK"));
+
+  if (!enable ||
+      *line == ';' ||                 /* comment */
+      (NULL != strstr( line, "==."))) /* dirty check for _G.debugLine */
+    return;                           /* nothing to do */
+
+  DEBUG(printf("%s\n",line);)
+
+  if (!strncmp (line,"mov",3))
+    {
+      /* check literal mov to accumulator */
+      if(!strncmp (line,"mov\ta,#0x",9))
+        {
+          char *s;
+          int value;
+
+          value = strtol (line+7, &s, 16);
+          if (s != line+7)
+              REGS8051_SET (A_IDX, value); /* valid hex found */
+          else
+              REGS8051_UNSET (A_IDX); /* probably a symbol (not handled) */
+
+          return;
+        }
+
+      if (!strncmp (line,"mov\ta,r",7))
+        {
+          /* handle mov from Rx if Rx is known */
+          regs *r = getReg(line+7);
+          if (r && r->valueKnown)
+            {
+              REGS8051_SET (A_IDX, r->value);
+              return;
+            }
+          REGS8051_UNSET (A_IDX);
+          return;
+        }
+
+      if (!strncmp (line,"mov\ta",5))
+        {
+          REGS8051_UNSET (A_IDX);
+          return;
+        }
+
+      if (!strncmp (line,"movc\ta",6) ||
+          !strncmp (line,"movx\ta",6))
+        {
+          REGS8051_UNSET (A_IDX);
+          return;
+        }
+
+      /* move direct to symbol, do not care */
+      if (!strncmp (line,"mov\t_",5) ||
+          !strncmp (line,"mov\t(_",6))
+        return;
+
+      /* check literal mov to register */
+      if (!strncmp (line,"mov\tr",5))
+        {
+          char *s;
+          int value;
+          int regNum;
+
+          regNum = strtol (line+5, &s, 16);
+          if (s == line+6)
+            {
+              value = strtol (line+8, &s, 16);
+              if ((s != line+8) && !strncmp (line+6,",#0x",4))
+                REGS8051_SET (Rx_NUM_TO_IDX(regNum), value);
+              else
+                REGS8051_UNSET (Rx_NUM_TO_IDX(regNum));
+              return;
+            }
+        }
+
+      /* mov to psw can change register bank */
+      if (!strncmp (line,"mov\tpsw,",8))
+        {
+          invalidateAllRx();
+          return;
+        }
+
+      /* no tracking of these, so we do not care */
+      if (!strncmp (line,"mov\tdptr,#",10) ||
+          !strncmp (line,"mov\tdpl,",8) ||
+          !strncmp (line,"mov\tdph,",8) ||
+          !strncmp (line,"mov\tsp,",7) ||
+          !strncmp (line,"mov\tb,",6))
+        return;
+
+      /* mov to xdata memory does not change registers */
+      if (!strncmp (line,"movx\t@",6))
+        return;
+
+      if (!strncmp (line,"mov\t@",5))
+        {
+          invalidateAllRx();
+          return;
+        }
+    }
+
+  /* no tracking of SP */
+  if (!strncmp (line,"push",4))
+    return;
+
+  if (!strncmp (line,"pop\ta",5))
+    {
+      if (!strncmp (line+4,"acc",3)){ REGS8051_UNSET (A_IDX); return; }
+      if (!strncmp (line+4,"ar2",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (2)); return; }
+      if (!strncmp (line+4,"ar3",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (3)); return; }
+      if (!strncmp (line+4,"ar4",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (4)); return; }
+      if (!strncmp (line+4,"ar5",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (5)); return; }
+      if (!strncmp (line+4,"ar6",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (6)); return; }
+      if (!strncmp (line+4,"ar7",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (7)); return; }
+      if (!strncmp (line+4,"ar0",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (0)); return; }
+      if (!strncmp (line+4,"ar1",3)){ REGS8051_UNSET (Rx_NUM_TO_IDX (1)); return; }
+    }
+
+  if (!strncmp (line,"inc",3))
+    {
+      /* no tracking of dptr, ignore */
+      if (!strcmp (line,"inc\tdptr") ||
+          !strcmp (line,"inc\tdph") ||
+          !strcmp (line,"inc\tdpl"))
+        return;
+
+      if (!strcmp (line,"inc\ta"))
+        {
+          if (regs8051[A_IDX].valueKnown)
+            REGS8051_SET (A_IDX, regs8051[A_IDX].value+1);
+          return;
+        }
+
+      if(!strncmp (line,"inc\tr",5))
+        {
+          regs *r = getReg(line+5);
+          if (r && r->valueKnown)
+            {
+              REGS8051_SET (r->rIdx, r->value+1);
+            }
+          return;
+        }
+    }
+
+  /* some bit in acc is cleared
+     MB: I'm too lazy to find out which right now */
+  if (!strncmp (line,"jbc\tacc",7))
+    {
+      REGS8051_UNSET (A_IDX);
+      return;
+    }
+
+  /* unfortunately the label typically following these
+     will cause loss of tracking */
+  if (!strncmp (line,"jc\t",3) ||
+      !strncmp (line,"jnc\t",4) ||
+      !strncmp (line,"jb\t",3) ||
+      !strncmp (line,"jnb\t",4) ||
+      !strncmp (line,"jbc\t",4))
+    return;
+
+  /* if branch not taken in "cjne r2,#0x08,somewhere" 
+     r2 is known to be 8 */
+  if (!strncmp (line,"cjne",4))
+    {
+      if(!strncmp (line,"cjne\ta,#0x",10))
+        {
+          char *s;
+          int value;
+
+          value = strtol (line+8, &s, 16);
+          if (s != line+8)
+              REGS8051_SET (A_IDX, value); /* valid hex found */
+        }
+      if(!strncmp (line,"cjne\tr",6))
+        {
+          char *s;
+          int value;
+          regs *r = getReg(line+6);
+          value = strtol (line+8, &s, 16);
+          if (r && s != line+8)
+              REGS8051_SET (r->rIdx, value); /* valid hex found */
+        }
+      return;
+    }
+
+  /* acc eventually known to be zero */
+  if (!strncmp (line,"jz\t",3))
+    return;
+
+  /* acc eventually known to be zero */
+  if (!strncmp (line,"jnz\t",4))
+    {
+      REGS8051_SET (A_IDX, 0x00); // branch not taken
+      return;
+    }
+
+  if (!strncmp (line,"djnz\tr",6))
+    {
+      char *s;
+      int regNum;
+
+      regNum = strtol (line+6, &s, 16);
+      if (s == line+7)
+        {
+          //REGS8051_UNSET (Rx_NUM_TO_IDX(regNum));
+          REGS8051_SET (Rx_NUM_TO_IDX(regNum), 0x00); // branch not taken
+          return;
+        }
+    }
+
+  /* only carry bit, so we do not care */
+  if (!strncmp (line,"setb\tc",6) ||
+      !strncmp (line,"clr\tc",5) ||
+      !strncmp (line,"cpl\tc",5))
+    return;
+
+  if (!strncmp (line,"add\ta,",6) ||
+      !strncmp (line,"addc\ta,",7)||
+      !strncmp (line,"subb\ta,",7)||
+      !strncmp (line,"xrl\ta,",6) ||
+      !strncmp (line,"orl\ta,",6) ||
+      !strncmp (line,"anl\ta,",6) ||
+      !strncmp (line,"da\ta",4)   ||
+      !strncmp (line,"rlc\ta,",6) ||
+      !strncmp (line,"rrc\ta,",6) ||
+      !strncmp (line,"setb\ta",6) ||
+      !strncmp (line,"clrb\ta,",7)||
+      !strncmp (line,"cpl\tacc",7))
+    {
+      /* could also handle f.e. "add a,Rx" if a, Rx are known or "xrl a,#0x08" */
+      REGS8051_UNSET (A_IDX);
+      return;
+    }
+
+
+  if (!strncmp (line,"dec",3))
+    {
+      /* no tracking of dptr, so we would not care */
+      if (!strcmp (line,"dec\tdph") ||
+          !strcmp (line,"dec\tdpl"))
+        return;
+
+      if (!strcmp (line,"dec\ta"))
+        {
+          if (regs8051[A_IDX].valueKnown)
+            REGS8051_SET (A_IDX, regs8051[A_IDX].value-1);
+          return;
+        }
+
+      if(!strncmp (line,"dec\tr",5))
+        {
+          regs *r = getReg(line+5);
+          if (r && r->valueKnown)
+            {
+              REGS8051_SET (r->rIdx, r->value-1);
+            }
+          return;
+        }
+    }
+
+
+  if (!strcmp (line,"clr\ta"))
+    {
+      REGS8051_SET (A_IDX, 0);
+      return;
+    }
+
+  if (!strcmp (line,"cpl\ta"))
+    {
+      if (regs8051[A_IDX].valueKnown)
+        REGS8051_SET (A_IDX, ~regs8051[A_IDX].value);
+      return;
+    }
+  if (!strcmp (line,"rl\ta"))
+    {
+      if (regs8051[A_IDX].valueKnown)
+        REGS8051_SET (A_IDX, (regs8051[A_IDX].value<<1) | 
+                             (regs8051[A_IDX].value>>7) );
+      return;
+    }
+  if (!strcmp (line,"rr\ta"))
+    {
+      if (regs8051[A_IDX].valueKnown)
+        REGS8051_SET (A_IDX, (regs8051[A_IDX].value>>1) |
+                             (regs8051[A_IDX].value<<7));
+      return;
+    }
+  if (!strcmp (line,"swap\ta"))
+    {
+      if (regs8051[A_IDX].valueKnown)
+        REGS8051_SET (A_IDX, (regs8051[A_IDX].value>>4) |
+                             (regs8051[A_IDX].value<<4));
+      return;
+    }
+
+  if (!strncmp (line,"mul",3) ||
+      !strncmp (line,"div",3)
+      )
+    {
+      REGS8051_UNSET (A_IDX);
+      REGS8051_UNSET (B_IDX);
+      return;
+    }
+
+  /* assuming these library functions have no side-effects */
+  if (!strcmp (line,"lcall"))
+    {
+      if (!strcmp (line,"lcall\t__gptrput"))
+        {
+          /* invalidate R0..R7 because they might have been changed */
+          /* MB: too paranoid ? */
+          //invalidateAllRx();
+          return;
+        }
+      if (!strcmp (line,"lcall\t__gptrget"))
+        {
+          REGS8051_UNSET (A_IDX);
+          return;
+        }
+      if (!strcmp (line,"lcall\t__decdptr"))
+        {
+          return;
+        }
+     }
+
+  if (!strncmp (line,"xch\ta,r",7))
+    {
+      /* handle xch acc with Rn */
+      regs *r = getReg(line+7);
+      if (r)
+        {
+          unsigned swap;
+          swap = r->valueKnown;
+          r->valueKnown = regs8051[A_IDX].valueKnown;
+          regs8051[A_IDX].valueKnown = swap;
+
+          swap = r->value;
+          r->value = regs8051[A_IDX].value;
+          regs8051[A_IDX].value = swap;
+          return;
+        }
+    }
+
+  /* all others unrecognized, invalidate */
+  invalidateAll();
+}
+
+
+/* expects f.e. "#0x01" and returns either "#0x01"
+   if the value is not known to be within registers
+   or "a" or "r0".."r7".
+   (mov a,r7 or add a,r7 need one byte whereas
+    mov a,#0x01 or add a,#0x01 would take two
+ */
+char * rtrackGetLit(const char *x)
+{
+  unsigned int i;
+
+  char *s;
+
+  if (enable != 1)
+    return (char *)x;
+
+  /* was it a numerical literal? */
+  if (*x == '#')
+    {
+      int val = strtol (x+1, &s, 16);
+      if (x+1 != s)
+        {
+          /* try to get from acc */
+          regs *r = &regs8051[A_IDX];
+          if (r->valueKnown &&
+              r->value == val)
+            {
+              D(emitcode (";", "genFromRTrack 0x%02x=%s", val, r->name));
+              return r->name;
+            }
+          /* try to get from register R0..R7 */
+          for (i=0; i<8; i++)
+            {
+              regs *r = &regs8051[Rx_NUM_TO_IDX(i)];
+              if (r->valueKnown &&
+                  r->value == val)
+                {
+                  D(emitcode (";", "genFromRTrack 0x%02x=%s", val, r->name));
+                  return r->name;
+                }
+            }
+        }
+      else
+        {
+          /* probably a symbolic literal as in "mov r3,#(_i+1)",
+             not handled... */
+        }
+    }
+
+  return (char *)x;
+}
+
+/* Similar to the above function 
+   As the destination is the accumulator try harder yet and
+   try to generate the result with arithmetic operations */
+int rtrackMoveALit (const char *x)
+{
+
+  if (enable != 1)
+    return 0;
+
+  /* if it is a literal mov try to get it cheaper */
+  if ( *x == '#' )
+    {
+      regs *a = &regs8051[A_IDX];
+
+      char *s;
+      int val = strtol (x+1, &s, 16);
+
+      /* was it a numerical literal? */
+      if (x+1 != s)
+        {
+          /* prefer mov a,#0x00 */
+          if (val == 0 &&
+              ((a->valueKnown && a->value != 0) ||
+               !a->valueKnown))
+            {
+              /* peepholes convert to clr a */
+              /* MB: why not here ? */
+              emitcode ("mov", "a,#0x00");
+              return 1;
+            }
+
+          if (a->valueKnown)
+            {
+              /* already there? */
+              if (val == a->value)
+                {
+                  D(emitcode (";", "genFromRTrack acc=0x%02x", a->value));
+                  return 1;
+                }
+
+              /* can be calculated with an instruction
+                 that does not change flags from acc itself? */
+              if (val == ((a->value+1) & 0xff) )
+                {
+                  D(emitcode (";", "genFromRTrack 0x%02x=0x%02x+1", val, a->value));
+                  emitcode ("inc", "a");
+                  return 1;
+                }
+              if (val == ((a->value-1) & 0xff) )
+                {
+                  D(emitcode (";", "genFromRTrack 0x%02x=0x%02x-1", val, a->value));
+                  emitcode ("dec", "a");
+                  return 1;
+                }
+              if (val == ((~a->value) & 0xff) )
+                {
+                  D(emitcode (";", "genFromRTrack 0x%02x=~0x%02x", val, a->value));
+                  emitcode ("cpl", "a");
+                  return 1;
+                }
+              if (val == (((a->value>>1) |
+                           (a->value<<7)) & 0xff))
+                {
+                  D(emitcode (";", "genFromRTrack 0x%02x=rr(0x%02x)", val, a->value));
+                  emitcode ("rr", "a");
+                  return 1;
+                }
+              if (val == (((a->value<<1) |
+                           (a->value>>7)) & 0xff ))
+                {
+                  D(emitcode (";", "genFromRTrack 0x%02x=rl(0x%02x)", val, a->value));
+                  emitcode ("rl", "a");
+                  return 1;
+                }
+              if (val == ( ((a->value & 0x0f)<<4) |
+                           ((a->value & 0xf0)>>4) ))
+                {
+                  D(emitcode (";", "genFromRTrack 0x%02x=swap(0x%02x)", val, a->value));
+                  emitcode ("swap", "a");
+                  return 1;
+                }
+              /* Decimal Adjust Accumulator (da a) changes flags so not used */
+            }
+
+
+          {
+            unsigned int i;
+            char *ptr= rtrackGetLit(x);
+
+            if (x != ptr)
+              {
+                /* could get from register, fine */
+                emitcode ("mov", "a,%s", ptr);
+                return 1;
+              }
+
+            /* not yet giving up - try to calculate from register R0..R7 */
+            for (i=0; i<8; i++)
+              {
+                regs *r = &regs8051[Rx_NUM_TO_IDX(i)];
+
+                if (a->valueKnown && r->valueKnown)
+                  {
+                    /* calculate with a single byte instruction from R0..R7? */
+                    if (val == (a->value | r->value))
+                      {
+                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x|0x%02x",
+                                    val, a->value, r->value));
+                        emitcode ("orl", "a,%s",r->name);
+                        return 1;
+                      }
+                    if (val == (a->value & r->value))
+                      {
+                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x&0x%02x",
+                                    val, a->value, r->value));
+                        emitcode ("anl", "a,%s", r->name);
+                        return 1;
+                      }
+                    if (val == (a->value ^ r->value))
+                      {
+                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x^0x%02x",
+                                    val, a->value, r->value));
+                        emitcode ("xrl", "a,%s", r->name);
+                        return 1;
+                      }
+                    /* changes flags (does that matter?)
+                    if (val == (a->value + r->value))
+                      {
+                        D(emitcode (";", "genFromRTrack 0x%02x=0x%02x+%0x02x",
+                                    val, a->value, r->value));
+                        emitcode ("add", "a,%s",r->name);
+                        return 1;
+                      }
+                    so not used */
+                  }
+              }
+          }
+      }
+    }
+
+  return 0;
+}
+