cpu: Physical register structural + flat indexing

Mimic the changes done on the architectural register indexes on the
physical register indexes. This is specific to the O3 model. The
structure, called PhysRegId, contains a register class, a register
index and a flat register index. The flat register index is kept
because it is useful in some cases where the type of register is not
important (dependency graph and scoreboard for example). Instead
of directly using the structure, most of the code is working with
a const PhysRegId* (typedef to PhysRegIdPtr). The actual PhysRegId
objects are stored in the regFile.

Change-Id: Ic879a3cc608aa2f34e2168280faac1846de77667
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/2701
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

1 files changed, 37 insertions, 9 deletions

diff --git a/src/cpu/o3/regfile.cc b/src/cpu/o3/regfile.cc
index e1d84c683..ee8d07b3e 100644
--- a/src/cpu/o3/regfile.cc
+++ b/src/cpu/o3/regfile.cc
@@ -41,18 +41,43 @@ PhysRegFile::PhysRegFile(unsigned _numPhysicalIntRegs,
     : intRegFile(_numPhysicalIntRegs),
       floatRegFile(_numPhysicalFloatRegs),
       ccRegFile(_numPhysicalCCRegs),
-      baseFloatRegIndex(_numPhysicalIntRegs),
-      baseCCRegIndex(_numPhysicalIntRegs + _numPhysicalFloatRegs),
+      numPhysicalIntRegs(_numPhysicalIntRegs),
+      numPhysicalFloatRegs(_numPhysicalFloatRegs),
+      numPhysicalCCRegs(_numPhysicalCCRegs),
       totalNumRegs(_numPhysicalIntRegs
                    + _numPhysicalFloatRegs
                    + _numPhysicalCCRegs)
 {
+    PhysRegIndex phys_reg;
+    PhysRegIndex flat_reg_idx = 0;
+
     if (TheISA::NumCCRegs == 0 && _numPhysicalCCRegs != 0) {
         // Just make this a warning and go ahead and allocate them
         // anyway, to keep from having to add checks everywhere
         warn("Non-zero number of physical CC regs specified, even though\n"
              "    ISA does not use them.\n");
     }
+    // The initial batch of registers are the integer ones
+    for (phys_reg = 0; phys_reg < numPhysicalIntRegs; phys_reg++) {
+        intRegIds.emplace_back(IntRegClass, phys_reg, flat_reg_idx++);
+    }
+
+    // The next batch of the registers are the floating-point physical
+    // registers; put them onto the floating-point free list.
+    for (phys_reg = 0; phys_reg < numPhysicalFloatRegs; phys_reg++) {
+        floatRegIds.emplace_back(FloatRegClass, phys_reg, flat_reg_idx++);
+    }
+
+    // The rest of the registers are the condition-code physical
+    // registers; put them onto the condition-code free list.
+    for (phys_reg = 0; phys_reg < numPhysicalCCRegs; phys_reg++) {
+        ccRegIds.emplace_back(CCRegClass, phys_reg, flat_reg_idx++);
+    }
+
+    // Misc regs have a fixed mapping but still need PhysRegIds.
+    for (phys_reg = 0; phys_reg < TheISA::NumMiscRegs; phys_reg++) {
+        miscRegIds.emplace_back(MiscRegClass, phys_reg, 0);
+    }
 }
 
 
@@ -60,22 +85,25 @@ void
 PhysRegFile::initFreeList(UnifiedFreeList *freeList)
 {
     // Initialize the free lists.
-    PhysRegIndex reg_idx = 0;
+    int reg_idx = 0;
 
     // The initial batch of registers are the integer ones
-    while (reg_idx < baseFloatRegIndex) {
-        freeList->addIntReg(reg_idx++);
+    for (reg_idx = 0; reg_idx < numPhysicalIntRegs; reg_idx++) {
+        assert(intRegIds[reg_idx].regIdx == reg_idx);
+        freeList->addIntReg(&intRegIds[reg_idx]);
     }
 
     // The next batch of the registers are the floating-point physical
     // registers; put them onto the floating-point free list.
-    while (reg_idx < baseCCRegIndex) {
-        freeList->addFloatReg(reg_idx++);
+    for (reg_idx = 0; reg_idx < numPhysicalFloatRegs; reg_idx++) {
+        assert(floatRegIds[reg_idx].regIdx == reg_idx);
+        freeList->addFloatReg(&floatRegIds[reg_idx]);
     }
 
     // The rest of the registers are the condition-code physical
     // registers; put them onto the condition-code free list.
-    while (reg_idx < totalNumRegs) {
-        freeList->addCCReg(reg_idx++);
+    for (reg_idx = 0; reg_idx < numPhysicalCCRegs; reg_idx++) {
+        assert(ccRegIds[reg_idx].regIdx == reg_idx);
+        freeList->addCCReg(&ccRegIds[reg_idx]);
     }
 }