diff --git a/lib/soft386/opgroups.c b/lib/soft386/opgroups.c
index c228b2920f0..f011303ec17 100644
--- a/lib/soft386/opgroups.c
+++ b/lib/soft386/opgroups.c
@@ -243,14 +243,106 @@ SOFT386_OPCODE_HANDLER(Soft386OpcodeGroupC1)
 
 SOFT386_OPCODE_HANDLER(Soft386OpcodeGroupC6)
 {
-    UNIMPLEMENTED;
-    return FALSE; // TODO: NOT IMPLEMENTED
+    UCHAR Immediate;
+    SOFT386_MOD_REG_RM ModRegRm;
+    BOOLEAN AddressSize = State->SegmentRegs[SOFT386_REG_CS].Size;
+
+    if (State->PrefixFlags & SOFT386_PREFIX_ADSIZE)
+    {
+        /* The ADSIZE prefix toggles the size */
+        AddressSize = !AddressSize;
+    }
+
+    if (!Soft386ParseModRegRm(State, AddressSize, &ModRegRm))
+    {
+        /* Exception occurred */
+        return FALSE;
+    }
+
+    if (ModRegRm.Register != 0)
+    {
+        /* Invalid */
+        Soft386Exception(State, SOFT386_EXCEPTION_UD);
+        return FALSE;
+    }
+
+    /* Get the immediate operand */
+    if (!Soft386FetchByte(State, &Immediate))
+    {
+        /* Exception occurred */
+        return FALSE;
+    }
+
+    return Soft386WriteModrmByteOperands(State,
+                                         &ModRegRm,
+                                         FALSE,
+                                         Immediate);
 }
 
 SOFT386_OPCODE_HANDLER(Soft386OpcodeGroupC7)
 {
-    UNIMPLEMENTED;
-    return FALSE; // TODO: NOT IMPLEMENTED
+    SOFT386_MOD_REG_RM ModRegRm;
+    BOOLEAN OperandSize, AddressSize;
+    
+    OperandSize = AddressSize = State->SegmentRegs[SOFT386_REG_CS].Size;
+
+    if (State->PrefixFlags & SOFT386_PREFIX_OPSIZE)
+    {
+        /* The OPSIZE prefix toggles the size */
+        OperandSize = !OperandSize;
+    }
+
+    if (State->PrefixFlags & SOFT386_PREFIX_ADSIZE)
+    {
+        /* The ADSIZE prefix toggles the size */
+        AddressSize = !AddressSize;
+    }
+
+    if (!Soft386ParseModRegRm(State, AddressSize, &ModRegRm))
+    {
+        /* Exception occurred */
+        return FALSE;
+    }
+
+    if (ModRegRm.Register != 0)
+    {
+        /* Invalid */
+        Soft386Exception(State, SOFT386_EXCEPTION_UD);
+        return FALSE;
+    }
+
+    if (OperandSize)
+    {
+        ULONG Immediate;
+
+        /* Get the immediate operand */
+        if (!Soft386FetchDword(State, &Immediate))
+        {
+            /* Exception occurred */
+            return FALSE;
+        }
+
+        return Soft386WriteModrmDwordOperands(State,
+                                              &ModRegRm,
+                                              FALSE,
+                                              Immediate);
+    }
+    else
+    {
+        USHORT Immediate;
+
+        /* Get the immediate operand */
+        if (!Soft386FetchWord(State, &Immediate))
+        {
+            /* Exception occurred */
+            return FALSE;
+        }
+
+        return Soft386WriteModrmWordOperands(State,
+                                             &ModRegRm,
+                                             FALSE,
+                                             Immediate);
+    }
 }
 
 SOFT386_OPCODE_HANDLER(Soft386OpcodeGroupD0)