Fix SRA and SRAV instructions

This implementation is correct one but there is no guarantee that it
will work with all compilers so we should always check on given platform
that tests pass (and potentially fix it).

1 files changed, 4 insertions, 4 deletions

diff --git a/qtmips_machine/alu.cpp b/qtmips_machine/alu.cpp
index 0d40bf0..f266c9b 100644
--- a/qtmips_machine/alu.cpp
+++ b/qtmips_machine/alu.cpp
@@ -11,15 +11,15 @@ std::uint32_t machine::alu_operate(enum AluOp operation, std::uint32_t s, std::u
         case ALU_OP_SRL:
             return t >> sa;
         case ALU_OP_SRA:
-            // TODO is this correct implementation? (Should we be masking top most bit?)
-            return ((t & 0x7fffffff) >> sa) | (t & 0x80000000);
+            // Note: This might be broken with some compilers but works with gcc
+            return (std::int32_t)t >> sa;
         case ALU_OP_SLLV:
             return t << s;
         case ALU_OP_SRLV:
             return t >> s;
         case ALU_OP_SRAV:
-            // TODO is this correct implementation? (Should we be masking top most bit?)
-            return ((t & 0x7fffffff) >> s) | (t & 0x80000000);
+            // Note: same note as in case of SRA
+            return (std::int32_t)t >> s;
         case ALU_OP_JR:
         case ALU_OP_JALR:
             // Do nothing as we solve this when we are handling program counter in instruction decode (handle_pc)