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http://www.devx.com/amd/Article/16018/204
Most modern operating systems have built-in support for Compatibility Mode. Microsoft Windows supports this through the Windows on Windows subsystem (WoW). The WOW.DLL converts function arguments from 32-bit to 64-bit and return values from 64-bit to 32-bit. This is a low-overhead conversion, as most of the calculations involve adding leading zeros; the address translation is from flat 32-bit to flat 64-bit. Figure 1 illustrates how 32-bit and 64-bit applications interact with the Windows operating system.
Los mas modernos sistemas operativos tienen enbebido el soporte para COMPATIBILIY MODE
Microsoft Windows soporta esto a traves del subsistema Windows en Windows(WoW). La WOW.DLL convierte los argumentos de 32 a 64Bits y los devueve de 64 a 32bits
Asi que si que cambia de submodo
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