Changes between Version 11 and Version 12 of CallingConventionsOverview

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Timestamp:
10/04/09 00:38:12 (5 years ago)
Author:
jkeenan
Comment:

minor spelling correction

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  • CallingConventionsOverview

    v11 v12  
    1 The purpose of the PCC branch is to unify the internal implentation of the calling conventions into one code path. The current implementation of subroutine, method, and NCI invocation uses multiple different styles of passing and receiving arguments. A call to a subroutine or method from PIR saves a pointer to the location of the opcode where the arguments were passed, and later extracts the variables or constants from that opcode instruction. A call to a subroutine or method from C may pass around a varargs list and extract the arguments from it later or create a call state struct. 
     1The purpose of the PCC branch is to unify the internal implementation of the calling conventions into one code path. The current implementation of subroutine, method, and NCI invocation uses multiple different styles of passing and receiving arguments. A call to a subroutine or method from PIR saves a pointer to the location of the opcode where the arguments were passed, and later extracts the variables or constants from that opcode instruction. A call to a subroutine or method from C may pass around a varargs list and extract the arguments from it later or create a call state struct. 
    22 
    33The new implementation standardizes argument passing for all calls (whether from PIR or C). Each call creates a call signature object right away, inserting arguments into the signature object from the opcode pointer or varargs list as soon as the call is made. Parameters are always extracted from a call signature object, and know nothing about the source of the call (they don't need to know what kind of environment invoked them, since all calls follow the same code path, and pass arguments the same way). NCI calls and what was previously known as PCCMETHOD calls also use the same argument passing strategy. Signature strings will be standardized on the PCC form (e.g. PI->S, for a call with a pmc and an integer argument, that returns a string result). The exception is NCI signatures, which will be left alone for now, but may be standardized later.