ARM: Generate condition code setting code based on which codes are set.

This change further eliminates cases where condition codes were being read
just so they could be written without change because the instruction in
question was supposed to preserve them. This is done by creating the condition
code code based on the input rather than just doing a simple substitution.

1 files changed, 46 insertions, 35 deletions

diff --git a/src/arch/arm/isa/insts/data.isa b/src/arch/arm/isa/insts/data.isa
index 41722914a..09f9621f1 100644
--- a/src/arch/arm/isa/insts/data.isa
+++ b/src/arch/arm/isa/insts/data.isa
@@ -51,27 +51,36 @@ let {{
         CpsrQ = (resTemp & 1) << 27;
     '''
 
-    calcCcCode = '''
-        uint16_t _ic, _iv, _iz, _in;
-        _in = (resTemp >> %(negBit)d) & 1;
-        _iz = (resTemp == 0);
-        _iv = %(ivValue)s & 1;
-        _ic = %(icValue)s & 1;
-
-        CondCodesNZ = (_in << 1) | _iz;
-        CondCodesC =  _ic;
-        CondCodesV =  _iv;
-
-        DPRINTF(Arm, "(in, iz, ic, iv) = (%%d, %%d, %%d, %%d)\\n",
-                     _in, _iz, _ic, _iv);
-       '''
+    def createCcCode(negBit, carry, overflow):
+        code = ""
+        code += '''
+            uint16_t _iz, _in;
+            _in = (resTemp >> %d) & 1;
+            _iz = (resTemp == 0);
+            CondCodesNZ = (_in << 1) | _iz;
+            DPRINTF(Arm, "(in, iz) = (%%d, %%d)\\n", _in, _iz);
+        ''' % negBit
+        if overflow and overflow != "none":
+            code +=  '''
+                uint16_t _iv;
+                _iv = %s & 1;
+                CondCodesV =  _iv;
+                DPRINTF(Arm, "(iv) = (%%d)\\n", _iv);
+            ''' % overflow
+        if carry and carry != "none":
+            code += '''
+                uint16_t _ic;
+                _ic = %s & 1;
+                CondCodesC =  _ic;
+                DPRINTF(Arm, "(ic) = (%%d)\\n", _ic);
+            ''' % carry
+        return code
 
     # Dict of code to set the carry flag. (imm, reg, reg-reg)
     oldC = 'CondCodesC'
-    oldV = 'CondCodesV'
     carryCode = {
-        "none": (oldC, oldC, oldC),
-        "llbit": (oldC, oldC, oldC),
+        "none": ("none", "none", "none"),
+        "llbit": ("none", "none", "none"),
         "saturate": ('0', '0', '0'),
         "overflow": ('0', '0', '0'),
         "ge": ('0', '0', '0'),
@@ -90,15 +99,15 @@ let {{
     }
     # Dict of code to set the overflow flag.
     overflowCode = {
-        "none": oldV,
-        "llbit": oldV,
+        "none": "none",
+        "llbit": "none",
         "saturate": '0',
         "overflow": '0',
         "ge": '0',
         "add": 'findOverflow(32, resTemp, Op1, secondOp)',
         "sub": 'findOverflow(32, resTemp, Op1, ~secondOp)',
         "rsb": 'findOverflow(32, resTemp, secondOp, ~Op1)',
-        "logic": oldV
+        "logic": "none"
     }
 
     secondOpRe = re.compile("secondOp")
@@ -118,11 +127,9 @@ let {{
         elif flagType == "ge":
             immCcCode = calcGECode
         else:
-            immCcCode = calcCcCode % {
-                "icValue": secondOpRe.sub(immOp2, cCode[0]),
-                "ivValue": secondOpRe.sub(immOp2, vCode),
-                "negBit": negBit
-            }
+            immCcCode = createCcCode(negBit, secondOpRe.sub(immOp2, cCode[0]),
+                                     secondOpRe.sub(immOp2, vCode))
+
         immCode = secondOpRe.sub(immOp2, code)
         immIop = InstObjParams(mnem, mnem.capitalize() + suffix, "DataImmOp",
                        {"code" : immCode,
@@ -149,6 +156,7 @@ let {{
         cCode = carryCode[flagType]
         vCode = overflowCode[flagType]
         negBit = 31
+        regCcCode = ""
         if flagType == "llbit":
             negBit = 63
         if flagType == "saturate":
@@ -156,12 +164,16 @@ let {{
         elif flagType == "ge":
             regCcCode = calcGECode
         else:
-            regCcCode = calcCcCode % {
-                "icValue": secondOpRe.sub(regOp2, cCode[1]),
-                "ivValue": secondOpRe.sub(regOp2, vCode),
-                "negBit": negBit
-            }
+            regCcCode = createCcCode(negBit,secondOpRe.sub(regOp2, cCode[1]),
+                                     secondOpRe.sub(regOp2, vCode))
+
         regCode = secondOpRe.sub(regOp2, code)
+
+        # If we end up needing CondCodesC then remove any trace of the OptShift
+        if re.search('(?<!OptShiftRm)CondCodesC(?!.*=)', regCode + regCcCode):
+            regCode = re.sub('OptShiftRmCondCodesC', 'CondCodesC', regCode)
+            regCcCode = re.sub('OptShiftRmCondCodesC', 'CondCodesC', regCcCode)
+
         regIop = InstObjParams(mnem, mnem.capitalize() + suffix, "DataRegOp",
                        {"code" : regCode, "is_ras_pop" : isRasPop,
                         "is_branch" : isBranch,
@@ -197,11 +209,10 @@ let {{
         elif flagType == "ge":
             regRegCcCode = calcGECode
         else:
-            regRegCcCode = calcCcCode % {
-                "icValue": secondOpRe.sub(regRegOp2, cCode[2]),
-                "ivValue": secondOpRe.sub(regRegOp2, vCode),
-                "negBit": negBit
-            }
+            regRegCcCode = createCcCode(negBit,
+                                        secondOpRe.sub(regRegOp2, cCode[2]),
+                                        secondOpRe.sub(regRegOp2, vCode))
+
         regRegCode = secondOpRe.sub(regRegOp2, code)
         regRegIop = InstObjParams(mnem, mnem.capitalize() + suffix,
                           "DataRegRegOp",