OZ v4.1 and later provides an advanced CALL subroutine mechanism that allows the application to execute a subroutine call in a 24bit address context, making it possible to reach executable code anywhere in the 4Mbit address space that is available in the Z88 machine hardware. Bank binding and restoration is automatically handled, if the subroutine to be called exist in another bank that is currently bound. EXTCALL helps to scale execution of large applications that span more than 32K of code mapped into the Z80 address space (typically, an application needs at least one segment to access dynamic memory).
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