riscv: Define register index constants using literals

To make it clearer what the register indices are for the semantically
meaningful registers defined by src/arch/riscv/registers.hh, the
constants that were defined using other constants were changed to use
the literal values of those constants.  This also removes the need to
use the M5_VAR_USED attribute.

Change-Id: I7cccbe45d3d820deb5149a5925415735f6ae2e61
Reviewed-on: https://gem5-review.googlesource.com/4080
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Alec Roelke <ar4jc@virginia.edu>

1 files changed, 4 insertions, 5 deletions

diff --git a/src/arch/riscv/registers.hh b/src/arch/riscv/registers.hh
index 114d7e9e1..01e385957 100644
--- a/src/arch/riscv/registers.hh
+++ b/src/arch/riscv/registers.hh
@@ -92,8 +92,8 @@ const int StackPointerReg = 2;
 const int GlobalPointerReg = 3;
 const int ThreadPointerReg = 4;
 const int FramePointerReg = 8;
+const int ReturnValueReg = 10;
 const std::vector<int> ReturnValueRegs = {10, 11};
-const int ReturnValueReg M5_VAR_USED = ReturnValueRegs[0];
 const std::vector<int> ArgumentRegs = {10, 11, 12, 13, 14, 15, 16, 17};
 const int AMOTempReg = 32;
 
@@ -118,10 +118,9 @@ const std::vector<std::string> FloatRegNames = {
     "ft8", "ft9", "ft10", "ft11"
 };
 
-const int SyscallNumReg M5_VAR_USED = ArgumentRegs[7];
-const std::vector<int> SyscallArgumentRegs = {ArgumentRegs[0], ArgumentRegs[1],
-    ArgumentRegs[2], ArgumentRegs[3]};
-const int SyscallPseudoReturnReg M5_VAR_USED = ReturnValueRegs[0];
+const int SyscallNumReg = 17;
+const std::vector<int> SyscallArgumentRegs = {10, 11, 12, 13};
+const int SyscallPseudoReturnReg = 10;
 
 enum MiscRegIndex {
     MISCREG_USTATUS = 0x000,