Inside Macintosh: Memory /

Chapter 4 - Memory Management Utilities / Memory Management Utilities Reference

Routines / Changing the Addressing Mode

GetMMUMode

To find out which address-translation mode (24-bit or 32-bit) is currently in use, use the GetMMUMode function.

FUNCTION GetMMUMode: SignedByte;

DESCRIPTION

The GetMMUMode function returns the address-translation mode currently in use. On exit, GetMMUMode returns one of the following constants:

CONST
   false32b    = 0;              {24-bit addressing mode}
   true32b     = 1;              {32-bit addressing mode}

SPECIAL CONSIDERATIONS

To find out which addressing mode was in effect at system startup, use the Gestalt function.

ASSEMBLY-LANGUAGE INFORMATION

To determine the current address-translation mode, you can test the contents of the global variable MMU32Bit. The value TRUE indicates that 32-bit mode is in effect.