Removed adpcm_decoder function and added comments in cacheSimInstrument.py

Signed-off-by: Gaurav Kukreja <gaurav@gauravk.in>

examples/Makefile

@@ -2,7 +2,7 @@ include ../Makefile.macros
 include Makefile.macros
 
 #EXAMPLES = sieve crc32 adpcm sha basicmath
-EXAMPLES = crc32 basicmath
+EXAMPLES = simple 
 #EXAMPLES = sha sieve
 #EXAMPLES = sha 
 STARTADR = 0x10000214

examples/adpcm/app_dir/adpcm.c

@@ -167,76 +167,3 @@ void adpcm_coder(short indata[], char outdata[], int len, struct adpcm_state *st
     state->index = index;
 }
 
-void adpcm_decoder(char indata[], short outdata[], int len, struct adpcm_state *state)
-{
-    signed char *inp;		/* Input buffer pointer */
-    short *outp;		/* output buffer pointer */
-    int sign;			/* Current adpcm sign bit */
-    int delta;			/* Current adpcm output value */
-    int step;			/* Stepsize */
-    int valpred;		/* Predicted value */
-    int vpdiff;			/* Current change to valpred */
-    int index;			/* Current step change index */
-    int inputbuffer;		/* place to keep next 4-bit value */
-    int bufferstep;		/* toggle between inputbuffer/input */
-
-    outp = outdata;
-    inp = (signed char *)indata;
-
-    valpred = state->valprev;
-    index = state->index;
-    step = stepsizeTable[index];
-
-    bufferstep = 0;
-    
-    for ( ; len > 0 ; len-- ) {
-	
-	/* Step 1 - get the delta value */
-	if ( bufferstep ) {
-	    delta = inputbuffer & 0xf;
-	} else {
-	    inputbuffer = *inp++;
-	    delta = (inputbuffer >> 4) & 0xf;
-	}
-	bufferstep = !bufferstep;
-
-	/* Step 2 - Find new index value (for later) */
-	index += indexTable[delta];
-	if ( index < 0 ) index = 0;
-	if ( index > 88 ) index = 88;
-
-	/* Step 3 - Separate sign and magnitude */
-	sign = delta & 8;
-	delta = delta & 7;
-
-	/* Step 4 - Compute difference and new predicted value */
-	/*
-	** Computes 'vpdiff = (delta+0.5)*step/4', but see comment
-	** in adpcm_coder.
-	*/
-	vpdiff = step >> 3;
-	if ( delta & 4 ) vpdiff += step;
-	if ( delta & 2 ) vpdiff += step>>1;
-	if ( delta & 1 ) vpdiff += step>>2;
-
-	if ( sign )
-	  valpred -= vpdiff;
-	else
-	  valpred += vpdiff;
-
-	/* Step 5 - clamp output value */
-	if ( valpred > 32767 )
-	  valpred = 32767;
-	else if ( valpred < -32768 )
-	  valpred = -32768;
-
-	/* Step 6 - Update step value */
-	step = stepsizeTable[index];
-
-	/* Step 7 - Output value */
-	*outp++ = valpred;
-    }
-
-    state->valprev = valpred;
-    state->index = index;
-}

examples/adpcm/ir_c/adpcm_IR.c

@@ -82,14 +82,14 @@ static int stepsizeTable[89] = {
     
 
 void adpcm_coder(short indata[], char outdata[], int len, struct adpcm_state *state) {
-  int valpred_43;
-  int index_42;
+  int valpred_41;
   int index_40;
-  int delta_39;
-  int step_38;
-  int step_37;
-  int valpred_36;
-  uintptr_t ivtmp_30;
+  int index_38;
+  int delta_37;
+  int step_36;
+  int step_35;
+  int valpred_34;
+  uintptr_t ivtmp_28;
   int bufferstep;
   int outputbuffer;
   int index;
@@ -115,13 +115,13 @@ adpcm_coderbb_2:
 adpcm_coderbb_3:
 //  # PRED: 2 [91.0%]  (true,exec)
   outp =  outdata;
-  ivtmp_30 = 0;
+  ivtmp_28 = 0;
   bufferstep = 1;
 //  # SUCC: 4 [100.0%]  (fallthru,exec)
 
 adpcm_coderbb_4:
 //  # PRED: 18 [91.0%]  (true,exec) 3 [100.0%]  (fallthru,exec)
-  diff = (int) *(short int *)((uintptr_t)indata + (uintptr_t)ivtmp_30) - valpred;
+  diff = (int) *(short int *)((uintptr_t)indata + (uintptr_t)ivtmp_28) - valpred;
   if (diff < 0)
     goto adpcm_coderbb_5;
   else
@@ -164,8 +164,8 @@ adpcm_coderbb_7:
 
 adpcm_coderbb_8:
 //  # PRED: 23 [100.0%]  (fallthru) 7 [100.0%]  (fallthru,exec)
-  step_37 = step >> 1;
-  if (diff >= step_37)
+  step_35 = step >> 1;
+  if (diff >= step_35)
     goto adpcm_coderbb_9;
   else
     goto adpcm_coderbb_10;
@@ -174,14 +174,14 @@ adpcm_coderbb_8:
 adpcm_coderbb_9:
 //  # PRED: 8 [50.0%]  (true,exec)
   delta = delta | 2;
-  diff = diff - step_37;
-  vpdiff = vpdiff + step_37;
+  diff = diff - step_35;
+  vpdiff = vpdiff + step_35;
 //  # SUCC: 10 [100.0%]  (fallthru,exec)
 
 adpcm_coderbb_10:
 //  # PRED: 8 [50.0%]  (false,exec) 9 [100.0%]  (fallthru,exec)
-  step_38 = step_37 >> 1;
-  if (diff >= step_38)
+  step_36 = step_35 >> 1;
+  if (diff >= step_36)
     goto adpcm_coderbb_11;
   else
     goto adpcm_coderbb_12;
@@ -190,7 +190,7 @@ adpcm_coderbb_10:
 adpcm_coderbb_11:
 //  # PRED: 10 [50.0%]  (true,exec)
   delta = delta | 1;
-  vpdiff = vpdiff + step_38;
+  vpdiff = vpdiff + step_36;
 //  # SUCC: 12 [100.0%]  (fallthru,exec)
 
 adpcm_coderbb_12:
@@ -203,23 +203,23 @@ adpcm_coderbb_12:
 
 adpcm_coderbb_13:
 //  # PRED: 12 [50.0%]  (true,exec)
-  valpred_36 = valpred - vpdiff;
+  valpred_34 = valpred - vpdiff;
   goto adpcm_coderbb_15;
 //  # SUCC: 15 [100.0%]  (fallthru,exec)
 
 adpcm_coderbb_14:
 //  # PRED: 12 [50.0%]  (false,exec)
-  valpred_36 = vpdiff + valpred;
+  valpred_34 = vpdiff + valpred;
 //  # SUCC: 15 [100.0%]  (fallthru,exec)
 
 adpcm_coderbb_15:
 //  # PRED: 13 [100.0%]  (fallthru,exec) 14 [100.0%]  (fallthru,exec)
-  valpred_43 = (valpred_36>-32768)?valpred_36:-32768;
-  valpred = (valpred_43<32767)?valpred_43:32767;
-  delta_39 = delta | sign;
-  index_40 = indexTable[delta_39] + index;
-  index_42 = (index_40>0)?index_40:0;
-  index = (index_42<88)?index_42:88;
+  valpred_41 = (valpred_34>-32768)?valpred_34:-32768;
+  valpred = (valpred_41<32767)?valpred_41:32767;
+  delta_37 = delta | sign;
+  index_38 = indexTable[delta_37] + index;
+  index_40 = (index_38>0)?index_38:0;
+  index = (index_40<88)?index_40:88;
   step = stepsizeTable[index];
   if (bufferstep != 0)
     goto adpcm_coderbb_16;
@@ -229,13 +229,13 @@ adpcm_coderbb_15:
 
 adpcm_coderbb_16:
 //  # PRED: 15 [50.0%]  (true,exec)
-  outputbuffer = delta_39 << 4 & 255;
+  outputbuffer = delta_37 << 4 & 255;
   goto adpcm_coderbb_18;
 //  # SUCC: 18 [100.0%]  (fallthru,exec)
 
 adpcm_coderbb_17:
 //  # PRED: 15 [50.0%]  (false,exec)
-  *outp =  (signed char) delta_39 & 15 | (signed char) outputbuffer;
+  *outp =  (signed char) delta_37 & 15 | (signed char) outputbuffer;
   outp = (uintptr_t)outp + 1;
 //  # SUCC: 18 [100.0%]  (fallthru,exec)
 
@@ -243,7 +243,7 @@ adpcm_coderbb_18:
 //  # PRED: 16 [100.0%]  (fallthru,exec) 17 [100.0%]  (fallthru,exec)
   bufferstep = bufferstep == 0;
   len = len + -1;
-  ivtmp_30 = ivtmp_30 + 2;
+  ivtmp_28 = ivtmp_28 + 2;
   if (len != 0)
     goto adpcm_coderbb_4;
   else
@@ -273,152 +273,3 @@ adpcm_coderbb_21:
 }
 
 
-
-void adpcm_decoder(char indata[], short int outdata[], int len, struct adpcm_state *state) {
-  int index_86;
-  int valpred_85;
-  int delta_83;
-  int index_82;
-  int valpred_81;
-  uintptr_t ivtmp_71;
-  int bufferstep;
-  int inputbuffer;
-  int index;
-  int vpdiff;
-  int valpred;
-  int step;
-  int delta;
-  signed char * inp;
-
-adpcm_decoderbb_2:
-//  # PRED: ENTRY [100.0%]  (fallthru,exec)
-  valpred_81 = state->valprev;
-  index = state->index;
-  step = stepsizeTable[index];
-  if (len > 0)
-    goto adpcm_decoderbb_3;
-  else
-    goto adpcm_decoderbb_18;
-//  # SUCC: 3 [91.0%]  (true,exec) 18 [9.0%]  (false,exec)
-
-adpcm_decoderbb_3:
-//  # PRED: 2 [91.0%]  (true,exec)
-  inp =  indata;
-  ivtmp_71 = 0;
-  bufferstep = 0;
-//  # SUCC: 4 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_4:
-//  # PRED: 17 [100.0%]  (fallthru,dfs_back,exec) 3 [100.0%]  (fallthru,exec)
-  if (bufferstep != 0)
-    goto adpcm_decoderbb_5;
-  else
-    goto adpcm_decoderbb_6;
-//  # SUCC: 5 [50.0%]  (true,exec) 6 [50.0%]  (false,exec)
-
-adpcm_decoderbb_5:
-//  # PRED: 4 [50.0%]  (true,exec)
-  delta = inputbuffer & 15;
-  goto adpcm_decoderbb_7;
-//  # SUCC: 7 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_6:
-//  # PRED: 4 [50.0%]  (false,exec)
-  inputbuffer = (int) *inp;
-  inp = (uintptr_t)inp + 1;
-  delta = inputbuffer >> 4 & 15;
-//  # SUCC: 7 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_7:
-//  # PRED: 5 [100.0%]  (fallthru,exec) 6 [100.0%]  (fallthru,exec)
-  index_82 = indexTable[delta] + index;
-  index_86 = (index_82>0)?index_82:0;
-  index = (index_86<88)?index_86:88;
-  delta_83 = delta & 7;
-  vpdiff = step >> 3;
-  if (delta_83 & 4 != 0)
-    goto adpcm_decoderbb_8;
-  else
-    goto adpcm_decoderbb_9;
-//  # SUCC: 8 [50.0%]  (true,exec) 9 [50.0%]  (false,exec)
-
-adpcm_decoderbb_8:
-//  # PRED: 7 [50.0%]  (true,exec)
-  vpdiff = vpdiff + step;
-//  # SUCC: 9 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_9:
-//  # PRED: 7 [50.0%]  (false,exec) 8 [100.0%]  (fallthru,exec)
-  if (delta_83 & 2 != 0)
-    goto adpcm_decoderbb_10;
-  else
-    goto adpcm_decoderbb_11;
-//  # SUCC: 10 [50.0%]  (true,exec) 11 [50.0%]  (false,exec)
-
-adpcm_decoderbb_10:
-//  # PRED: 9 [50.0%]  (true,exec)
-  vpdiff = vpdiff + (step >> 1);
-//  # SUCC: 11 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_11:
-//  # PRED: 9 [50.0%]  (false,exec) 10 [100.0%]  (fallthru,exec)
-  if (delta_83 & 1 != 0)
-    goto adpcm_decoderbb_12;
-  else
-    goto adpcm_decoderbb_13;
-//  # SUCC: 12 [50.0%]  (true,exec) 13 [50.0%]  (false,exec)
-
-adpcm_decoderbb_12:
-//  # PRED: 11 [50.0%]  (true,exec)
-  vpdiff = vpdiff + (step >> 2);
-//  # SUCC: 13 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_13:
-//  # PRED: 11 [50.0%]  (false,exec) 12 [100.0%]  (fallthru,exec)
-  if (delta & 8 != 0)
-    goto adpcm_decoderbb_14;
-  else
-    goto adpcm_decoderbb_15;
-//  # SUCC: 14 [50.0%]  (true,exec) 15 [50.0%]  (false,exec)
-
-adpcm_decoderbb_14:
-//  # PRED: 13 [50.0%]  (true,exec)
-  valpred = valpred_81 - vpdiff;
-  goto adpcm_decoderbb_16;
-//  # SUCC: 16 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_15:
-//  # PRED: 13 [50.0%]  (false,exec)
-  valpred = vpdiff + valpred_81;
-//  # SUCC: 16 [100.0%]  (fallthru,exec)
-
-adpcm_decoderbb_16:
-//  # PRED: 14 [100.0%]  (fallthru,exec) 15 [100.0%]  (fallthru,exec)
-  valpred_85 = (valpred>-32768)?valpred:-32768;
-  valpred_81 = (valpred_85<32767)?valpred_85:32767;
-  step = stepsizeTable[index];
-  *(short int *)((uintptr_t)outdata + (uintptr_t)ivtmp_71) = (short int) (short int) valpred_81;
-  len = len + -1;
-  ivtmp_71 = ivtmp_71 + 2;
-  if (len != 0)
-    goto adpcm_decoderbb_17;
-  else
-    goto adpcm_decoderbb_18;
-//  # SUCC: 17 [91.0%]  (true,exec) 18 [9.0%]  (false,exec)
-
-adpcm_decoderbb_17:
-//  # PRED: 16 [91.0%]  (true,exec)
-  bufferstep = bufferstep == 0;
-  goto adpcm_decoderbb_4;
-//  # SUCC: 4 [100.0%]  (fallthru,dfs_back,exec)
-
-adpcm_decoderbb_18:
-//  # PRED: 16 [9.0%]  (false,exec) 2 [9.0%]  (false,exec)
-  state->valprev = (short int) (short int) valpred_81;
-  state->index = (char) (char) index;
-  return;
-//  # SUCC: EXIT [100.0%] 
-
-}
-
-

examples/sieve/app_dir/erat_sieve_no_print.c

@@ -9,7 +9,7 @@ struct test {
   unsigned int k;
 } m = { 1, 1 };
 
-void sieve()
+void sieve_func()
  {
    unsigned int sieve[N];
  
@@ -51,6 +51,6 @@ void sieve()
 
 int main(void)
 {
-  sieve();
+  sieve_func();
   return 0;
 }

examples/sieve/ir_c/erat_sieve_no_print_IR.c

@@ -21,7 +21,7 @@ struct test {
 } m = { 1, 1 };
 
 
-void sieve() {
+void sieve_func() {
   int j_76;
   uintptr_t ivtmp_74;
   int i_72;
@@ -37,137 +37,137 @@ void sieve() {
   int i;
   unsigned int sieve[500000];
 
-sievebb_2:
+sieve_funcbb_2:
 //  # PRED: ENTRY [100.0%]  (fallthru,exec)
   ivtmp_68 = 0;
 //  # SUCC: 3 [100.0%]  (fallthru,exec)
 
-sievebb_3:
+sieve_funcbb_3:
 //  # PRED: 3 [99.0%]  (true,exec) 2 [100.0%]  (fallthru,exec)
   *(unsigned int*)((uintptr_t)&results + (uintptr_t)ivtmp_68) = 0;
   *(unsigned int*)((uintptr_t)&sieve + (uintptr_t)ivtmp_68) = 1;
   ivtmp_68 = ivtmp_68 + 4;
   if (ivtmp_68 != 2000000)
-    goto sievebb_3;
+    goto sieve_funcbb_3;
   else
-    goto sievebb_17;
+    goto sieve_funcbb_17;
 //  # SUCC: 3 [99.0%]  (true,exec) 17 [1.0%]  (false,exec)
 
-sievebb_17:
+sieve_funcbb_17:
 //  # PRED: 3 [1.0%]  (false,exec)
   ivtmp_49 = 6;
   ivtmp_58 = 4;
   i_72 = 2;
 //  # SUCC: 4 [100.0%]  (fallthru)
 
-sievebb_4:
+sieve_funcbb_4:
 //  # PRED: 7 [99.0%]  (true,exec) 17 [100.0%]  (fallthru)
   D_2263 = (unsigned int) i_72;
   if (*(unsigned int*)((uintptr_t)&sieve + (uintptr_t)D_2263 * 4) != 0)
-    goto sievebb_5;
+    goto sieve_funcbb_5;
   else
-    goto sievebb_7;
+    goto sieve_funcbb_7;
 //  # SUCC: 5 [50.0%]  (true,exec) 7 [50.0%]  (false,exec)
 
-sievebb_5:
+sieve_funcbb_5:
 //  # PRED: 4 [50.0%]  (true,exec)
   j_76 = (int) ivtmp_58;
   if (j_76 <= 499999)
-    goto sievebb_18;
+    goto sieve_funcbb_18;
   else
-    goto sievebb_7;
+    goto sieve_funcbb_7;
 //  # SUCC: 18 [91.0%]  (true,exec) 7 [9.0%]  (false,exec)
 
-sievebb_18:
+sieve_funcbb_18:
 //  # PRED: 5 [91.0%]  (true,exec)
   ivtmp_74 = ivtmp_49;
 //  # SUCC: 6 [100.0%]  (fallthru)
 
-sievebb_6:
+sieve_funcbb_6:
 //  # PRED: 6 [91.0%]  (true,exec) 18 [100.0%]  (fallthru)
   sieve[j_76] = 0;
   D_2252 = (unsigned int) j_76 + D_2263;
   j_76 = (int) D_2252;
   ivtmp_74 = D_2263 + ivtmp_74;
   if ((int) (ivtmp_74 - D_2263) <= 499999)
-    goto sievebb_6;
+    goto sieve_funcbb_6;
   else
-    goto sievebb_7;
+    goto sieve_funcbb_7;
 //  # SUCC: 6 [91.0%]  (true,exec) 7 [9.0%]  (false,exec)
 
-sievebb_7:
+sieve_funcbb_7:
 //  # PRED: 4 [50.0%]  (false,exec) 6 [9.0%]  (false,exec) 5 [9.0%]  (false,exec)
   i_72 = i_72 + 1;
   ivtmp_58 = ivtmp_58 + 2;
   ivtmp_49 = ivtmp_49 + 3;
   if (i_72 * i_72 <= 499999)
-    goto sievebb_4;
+    goto sieve_funcbb_4;
   else
-    goto sievebb_8;
+    goto sieve_funcbb_8;
 //  # SUCC: 4 [99.0%]  (true,exec) 8 [1.0%]  (false,exec)
 
-sievebb_8:
+sieve_funcbb_8:
 //  # PRED: 7 [1.0%]  (false,exec)
   j = 2;
   i = 0;
 //  # SUCC: 9 [100.0%]  (fallthru,exec)
 
-sievebb_9:
+sieve_funcbb_9:
 //  # PRED: 11 [99.0%]  (true,exec) 8 [100.0%]  (fallthru,exec)
   D_2240 = (unsigned int) j;
   if (*(unsigned int*)((uintptr_t)&sieve + (uintptr_t)D_2240 * 4) != 0)
-    goto sievebb_10;
+    goto sieve_funcbb_10;
   else
-    goto sievebb_11;
+    goto sieve_funcbb_11;
 //  # SUCC: 10 [50.0%]  (true,exec) 11 [50.0%]  (false,exec)
 
-sievebb_10:
+sieve_funcbb_10:
 //  # PRED: 9 [50.0%]  (true,exec)
   results[i] = D_2240;
   i = i + 1;
 //  # SUCC: 11 [100.0%]  (fallthru,exec)
 
-sievebb_11:
+sieve_funcbb_11:
 //  # PRED: 9 [50.0%]  (false,exec) 10 [100.0%]  (fallthru,exec)
   j = j + 1;
   if (j != 500000)
-    goto sievebb_9;
+    goto sieve_funcbb_9;
   else
-    goto sievebb_12;
+    goto sieve_funcbb_12;
 //  # SUCC: 9 [99.0%]  (true,exec) 12 [1.0%]  (false,exec)
 
-sievebb_12:
+sieve_funcbb_12:
 //  # PRED: 11 [1.0%]  (false,exec)
   if (results[0] == 0)
-    goto sievebb_16;
+    goto sieve_funcbb_16;
   else
-    goto sievebb_13;
+    goto sieve_funcbb_13;
 //  # SUCC: 16 [4.5%]  (true,exec) 13 [95.5%]  (false,exec)
 
-sievebb_13:
+sieve_funcbb_13:
 //  # PRED: 12 [95.5%]  (false,exec)
   ivtmp_36 = (uintptr_t)&results;
   D_2230 = ivtmp_36 + 1999996;
 //  # SUCC: 14 [100.0%]  (fallthru,exec)
 
-sievebb_14:
+sieve_funcbb_14:
 //  # PRED: 15 [98.9%]  (true,exec) 13 [100.0%]  (fallthru,exec)
   if (*(unsigned int*)((uintptr_t)ivtmp_36 + 4) == 0)
-    goto sievebb_16;
+    goto sieve_funcbb_16;
   else
-    goto sievebb_15;
+    goto sieve_funcbb_15;
 //  # SUCC: 16 [4.5%]  (true,exec) 15 [95.5%]  (false,exec)
 
-sievebb_15:
+sieve_funcbb_15:
 //  # PRED: 14 [95.5%]  (false,exec)
   ivtmp_36 = ivtmp_36 + 4;
   if (ivtmp_36 != D_2230)
-    goto sievebb_14;
+    goto sieve_funcbb_14;
   else
-    goto sievebb_16;
+    goto sieve_funcbb_16;
 //  # SUCC: 14 [98.9%]  (true,exec) 16 [1.1%]  (false,exec)
 
-sievebb_16:
+sieve_funcbb_16:
 //  # PRED: 14 [4.5%]  (true,exec) 15 [1.1%]  (false,exec) 12 [4.5%]  (true,exec)
   m.v = 0;
   return;
@@ -180,7 +180,7 @@ sievebb_16:
 int main(void) {
 mainbb_2:
 //  # PRED: ENTRY [100.0%]  (fallthru,exec)
-  sieve ();
+  sieve_func ();
   return 0;
 //  # SUCC: EXIT [100.0%] 
 

instrument/cacheSimInstrument.py

@@ -64,6 +64,7 @@ class FunctionInitState:
         self.name = name
         self.initRegState = initRegState
 
+# TODO: Probably need to change the name of this function
 def instrumentCache(listISCFileNames, listObjdumpFileNames, listBinaryFileNames):
     
     (listISCFunctions, listObjdumpFunctions) = match_cfg(listISCFileNames, 
@@ -104,6 +105,12 @@ def instrumentCache(listISCFileNames, listObjdumpFileNames, listBinaryFileNames)
                     logging.debug("\t %d: Instruction could not be emulated!" % lineNumObj)
                     return -1
                 
+                '''
+                Branch Instruction
+                  - If branch is to another function, add the called function to
+                    queue of pending functions.
+                  - Ignore all other branch instructions.
+                '''
                 m = re_branchInst.match(instObj)
                 if m is not None:
                     branchToFunction = m.group("labelFunction")
@@ -122,8 +129,21 @@ def instrumentCache(listISCFileNames, listObjdumpFileNames, listBinaryFileNames)
                                                                               initRegState))
                                 continue
                     else:
+                        logging.error("labelFunction in branch instruction could not be matched!")
                         continue
                 
+                '''
+                Store Instruction
+                  - Calculate the address in the store instruction.
+                  - If the address is in Stack, 
+                      - Writing to a local variable. Look up the list of local
+                        variables, and find which one.
+                      - Spilling Registers. Keep a dictionary mapping address 
+                        (relative to SP) and the content of the spilled register
+                  - If address not in stack, it could be accessing Global
+                    Variable. Look up table of Global Variables, and if no match
+                    found, report error.
+                '''
                 m = re_storeInst.match(instObj)
                 if m is not None:
                     for baseRegLabel in ["am2_1BaseReg", 
@@ -138,6 +158,7 @@ def instrumentCache(listISCFileNames, listObjdumpFileNames, listBinaryFileNames)
                     baseReg = m.group(baseRegLabel)
                     baseRegVal = armEmu.reg[baseReg].value
                     destReg = m.group("destReg")
+                    # Calculate store address based on addressing mode used.
                     if m.group("am2_2ImedOff") is not None:
                         strAdd = baseRegVal + int(m.group("am2_2ImedOff"))
                     elif m.group("am2_3OffsetReg") is not None:
@@ -171,6 +192,22 @@ def instrumentCache(listISCFileNames, listObjdumpFileNames, listBinaryFileNames)
                             logging.error(" %d: %s" % (lineNumObj, instObj))
                             continue
                 
+                '''
+                Load Instruction
+                  - If the base address is PC,
+                      - PC Relative Load instruction is used for Global Variables
+                        or Values more than 32 bit long. Check if the value
+                        loaded matches with address of a global variable.
+                  - If base address is not PC, calculate the address to be
+                    be loaded from. If the address is in stack, it may be
+                      - trying to load a local variable. Match the address to 
+                        a local variable. 
+                      - reading from a spilled register. Fetch the value of 
+                        the spilled register stored at the address.
+                  - If the address is not in stack, it must be trying to load
+                    content of a global variable. Match the address to a global
+                    variable. If matching is not found, report error.
+                '''
                 m = re_loadInst.match(instObj)
                 if m is not None:
                     for baseRegLabel in ["am2_1BaseReg", 
@@ -184,6 +221,7 @@ def instrumentCache(listISCFileNames, listObjdumpFileNames, listBinaryFileNames)
                             break
                     baseReg = m.group(baseRegLabel)
                     destReg = m.group("destReg")
+                    # PC Relative Load Instruction
                     if baseReg == "pc":
                         comment = m.group("comment")
                         m_comment = re.match("\s*([0-9a-f]*)\s*\<.*\>", comment)
@@ -202,6 +240,7 @@ def instrumentCache(listISCFileNames, listObjdumpFileNames, listBinaryFileNames)
                         continue
                     else:
                         baseRegVal = armEmu.reg[baseReg].value
+                        # Calculate load address based on addressing mode used.
                         if m.group("am2_2ImedOff") is not None:
                             ldrAdd = baseRegVal + int(m.group("am2_2ImedOff"))
                         elif m.group("am2_3OffsetReg") is not None: