Modifiers (Windows Embedded CE 6.0)
1/5/2010
ARM and THUMB support Microsoft-specific modifiers for interworking. The iwcall, iw16, and iw32 declspecs allow you to select which function calls are interworking.
Compared to a linker-generated thunking routine, the iwcall or iw16declspecs always result in faster code for interworking calls. The declspecs add only a single MOV instruction to the execution path, while a linker-generated thunking routine adds two instructions: a load from memory, and a branch.
See Also
Concepts
THUMB-enabled ARM Implementation
Linker-Generated Thunking Routines