diff --git a/reactos/lib/fast486/common.c b/reactos/lib/fast486/common.c
index 03378c2b3bd..1e9311ae00b 100644
--- a/reactos/lib/fast486/common.c
+++ b/reactos/lib/fast486/common.c
@@ -55,7 +55,7 @@ Fast486ReadMemory(PFAST486_STATE State,
     }
 
     /* Check for protected mode */
-    if (State->ControlRegisters[0] & FAST486_CR0_PE)
+    if (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
     {
         /* Privilege checks */
 
@@ -122,7 +122,7 @@ Fast486WriteMemory(PFAST486_STATE State,
     }
 
     /* Check for protected mode */
-    if (State->ControlRegisters[0] & FAST486_CR0_PE)
+    if (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE)
     {
         /* Privilege checks */
 
diff --git a/reactos/lib/fast486/common.inl b/reactos/lib/fast486/common.inl
index 57bf933633a..4990172fb1a 100644
--- a/reactos/lib/fast486/common.inl
+++ b/reactos/lib/fast486/common.inl
@@ -762,7 +762,7 @@ Fast486ParseModRegRm(PFAST486_STATE State,
     ModRegRm->Register = (ModRmByte >> 3) & 0x07;
 
     /* Check the mode */
-    if ((ModRmByte >> 6) == 3)
+    if (Mode == 3)
     {
         /* The second operand is also a register */
         ModRegRm->Memory = FALSE;
@@ -886,7 +886,6 @@ Fast486ParseModRegRm(PFAST486_STATE State,
                 /* [BX + SI] */
                 ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBX].LowWord
                                            + State->GeneralRegs[FAST486_REG_ESI].LowWord;
-
                 break;
             }
 
@@ -895,7 +894,6 @@ Fast486ParseModRegRm(PFAST486_STATE State,
                 /* [BX + DI] */
                 ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBX].LowWord
                                            + State->GeneralRegs[FAST486_REG_EDI].LowWord;
-
                 break;
             }
 
@@ -904,7 +902,6 @@ Fast486ParseModRegRm(PFAST486_STATE State,
                 /* SS:[BP + SI] */
                 ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBP].LowWord
                                            + State->GeneralRegs[FAST486_REG_ESI].LowWord;
-
                 break;
             }
 
@@ -913,7 +910,6 @@ Fast486ParseModRegRm(PFAST486_STATE State,
                 /* SS:[BP + DI] */
                 ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBP].LowWord
                                            + State->GeneralRegs[FAST486_REG_EDI].LowWord;
-
                 break;
             }
 
@@ -921,7 +917,6 @@ Fast486ParseModRegRm(PFAST486_STATE State,
             {
                 /* [SI] */
                 ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_ESI].LowWord;
-
                 break;
             }
 
@@ -929,7 +924,6 @@ Fast486ParseModRegRm(PFAST486_STATE State,
             {
                 /* [DI] */
                 ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EDI].LowWord;
-
                 break;
             }
 
@@ -953,7 +947,6 @@ Fast486ParseModRegRm(PFAST486_STATE State,
             {
                 /* [BX] */
                 ModRegRm->MemoryAddress = State->GeneralRegs[FAST486_REG_EBX].LowWord;
-
                 break;
             }
         }
diff --git a/reactos/lib/fast486/debug.c b/reactos/lib/fast486/debug.c
index 9af5b9620a2..974e99b3588 100644
--- a/reactos/lib/fast486/debug.c
+++ b/reactos/lib/fast486/debug.c
@@ -137,7 +137,7 @@ Fast486DumpState(PFAST486_STATE State)
 {
     DbgPrint("\nFast486DumpState -->\n");
     DbgPrint("\nCPU currently executing in %s mode at %04X:%08X\n",
-            (State->ControlRegisters[0] & FAST486_CR0_PE) ? "protected" : "real",
+            (State->ControlRegisters[FAST486_REG_CR0] & FAST486_CR0_PE) ? "protected" : "real",
              State->SegmentRegs[FAST486_REG_CS].Selector,
              State->InstPtr.Long);
     DbgPrint("\nGeneral purpose registers:\n"
diff --git a/reactos/lib/fast486/fast486.c b/reactos/lib/fast486/fast486.c
index 9df60e5c462..6bfd382017e 100644
--- a/reactos/lib/fast486/fast486.c
+++ b/reactos/lib/fast486/fast486.c
@@ -54,9 +54,9 @@ Fast486ExecutionControl(PFAST486_STATE State, FAST486_EXEC_CMD Command)
     /* Main execution loop */
     do
     {
-NextInst:
         if (!State->Halted)
         {
+NextInst:
             /* Check if this is a new instruction */
             if (State->PrefixFlags == 0) State->SavedInstPtr = State->InstPtr;
 
diff --git a/reactos/lib/fast486/opcodes.c b/reactos/lib/fast486/opcodes.c
index cadbd540d57..06b3f9eea54 100644
--- a/reactos/lib/fast486/opcodes.c
+++ b/reactos/lib/fast486/opcodes.c
@@ -4985,8 +4985,7 @@ FAST486_OPCODE_HANDLER(Fast486OpcodeLoop)
         /* Additional rule for LOOPNZ */
         if (State->Flags.Zf) Condition = FALSE;
     }
-
-    if (Opcode == 0xE1)
+    else if (Opcode == 0xE1)
     {
         /* Additional rule for LOOPZ */
         if (!State->Flags.Zf) Condition = FALSE;