OS_IsRunOnTwl

Syntax

#include <nitro/os.h>

BOOL OS_IsRunOnTwl( void );

Arguments

None.

Return Values

If TRUE, the application is running in TWL mode. The actual operating environment may be either an actual TWL system or the IS-TWL-DEBUGGER hardware.

If FALSE, the application is running in some other mode (that is, in NITRO mode). The actual operating environment may be either an actual NITRO console or IS-NITRO-DEBUGGER. This also applies to the case of running an application in NITRO mode on IS-TWL-DEBUGGER.

Description

Determines whether the program is running in TWL mode.

The OS_IsRunOnTwl function determines the operating mode. It does not determine the operating environment. For example, this function will sometimes return TRUE and sometimes return FALSE, even though the application is running on the IS-TWL-DEBUGGER hardware in both cases. In other words, programs run on IS-TWL-DEBUGGER will sometimes be run in TWL mode and will sometimes be run in NITRO mode.

OS_IsRunOnTwl is a useful function when creating TWL/NITRO hybrid ROMs. Hybrid ROMs will run in TWL mode on TWL, and in NITRO mode on NITRO. This function will return TRUE when run on a TWL, and FALSE when run on NITRO. This can be used to switch between code dynamically.

Example: How to Split Up Code That Supports NITRO/TWL Hybrid ROMs

if ( OS_IsRunOnTwl() )
{
// Code you want to run in TWL mode
}
else
{
// Code you want to run in NITRO mode
}

Also, while this will not be a very common case during normal development, you can use code like the following to match the #define directives defined for the SDK during development of libraries that support all three types of ROMs (NITRO-exclusive, TWL-exclusive, and NITRO/TWL hybrid). This code could be included in the library's source code.

Example: How to Split Up Code That Supports NITRO-Exclusive ROMs, TWL-Exclusive ROMs, and NITRO/TWL Hybrid ROMs

if ( OS_IsRunOnTwl() )
{
#ifdef SDK_TWL
// Code you want to run in TWL mode
#endif
}
else
{
#ifndef SDK_TWLLTD
// Code you want to run in NITRO mode
#endif
}

The OS_IsRunOnTwl function determines the platform at run time for hybrid ROMs, but for NITRO-exclusive ROMs, it will return the constant FALSE, and for TWL-exclusive ROMs, it will return the constant TRUE. When creating NITRO-exclusive ROMs or TWL-exclusive ROMs, you can expect the cases that do not match the conditions of the if statement to be deadstripped. However, we have used SDK_TWL (defined at compile time for TWL-exclusive ROMs and NITRO/TWL hybrid ROMs) and SDK_TWLLTD (defined at compile time for TWL-exclusive ROMs) to avoid undefined errors and other problems with functions appearing in the code that will be deadstripped.

Actual Values Due to the Environment:

Below is a list of values that can be returned by the OS_IsRunOnTwl function. There are no differences as a result of the build type (DEBUG, RELEASE, FINALROM).

Internal Operation

Makes the judgment based the value in the System Configuration register.

See Also

OS_Printf
OS_GetConsoleType

Revision History

2007/11/16 Added information.
2007/11/06 Initial version.

CONFIDENTIAL