Issue #852 add bswap command (#856)

* defined 'bswap' command as cbInstrBswap.  seems to work when the dest var is a register or user-defined var.  address args fail.

* rewrote bswap to use StringUtils::sprintf formatting.

* removed debug prints from byteswap func.  added error message when parsed arg isn't a variable.

* formatted.

src/dbg/instruction.cpp

@@ -858,6 +858,36 @@ CMDRESULT cbInstrPop(int argc, char* argv[])
     return STATUS_CONTINUE;
 }
 
+CMDRESULT cbInstrBswap(int argc, char* argv[])
+{
+    if(argc < 2)
+    {
+        dputs("not enough arguments!");
+        return STATUS_ERROR;
+    }
+    duint arg1 = 0;
+    int size = 0;
+    bool isvar = false;
+    if(!valfromstring(argv[1], &arg1, false, false, &size, &isvar))
+        return STATUS_ERROR;
+    if(!isvar)
+    {
+        dprintf("Invalid expression: \"%s\"", argv[1]);
+        return STATUS_ERROR;
+    }
+    duint result = arg1;
+    if(size == 2)
+        result = _byteswap_ushort((uint16)arg1);
+    else if(size == 4)
+        result = _byteswap_ulong((uint32)arg1);
+#ifdef _WIN64
+    else if(size == 8)
+        result = _byteswap_uint64(arg1);
+#endif
+    String swapcmd = StringUtils::sprintf("mov %s, " fhex, argv[1], result);
+    return cmddirectexec(swapcmd.c_str());
+}
+
 CMDRESULT cbInstrRefinit(int argc, char* argv[])
 {
     GuiReferenceInitialize("Script");

src/dbg/instruction.h

@@ -46,6 +46,7 @@ CMDRESULT cbInstrTest(int argc, char* argv[]);
 CMDRESULT cbInstrXor(int argc, char* argv[]);
 CMDRESULT cbInstrPush(int argc, char* argv[]);
 CMDRESULT cbInstrPop(int argc, char* argv[]);
+CMDRESULT cbInstrBswap(int argc, char* argv[]);
 
 CMDRESULT cbInstrRefinit(int argc, char* argv[]);
 CMDRESULT cbInstrRefadd(int argc, char* argv[]);

src/dbg/x64_dbg.cpp

@@ -261,6 +261,7 @@ static void registercommands()
     dbgcmdnew("xor", cbInstrXor, false);
     dbgcmdnew("push", cbInstrPush, true);
     dbgcmdnew("pop", cbInstrPop, true);
+    dbgcmdnew("bswap", cbInstrBswap, true);
 
     //script
     dbgcmdnew("scriptload", cbScriptLoad, false);