VMS Help MACRO, /MIGRATION, Compiler Directives, .JSB32 ENTRY *Conan The Librarian (sorry for the slow response - running on an old VAX) |
Declares the entry point of a JSB routine to the compiler. This directive does not preserve any VAX register values (R2 through R12) unless the PRESERVE parameter is specified. The routine itself may save and restore registers by pushing them on the stack, but this will not preserve the upper 32 bits of the registers. See also .JSB_ENTRY. WARNING The .JSB32_ENTRY directive can be a great time-saver if you are sure that you can use it. If you use .JSB32_ENTRY in a situation where the upper 32 bits of a register are being used, it may cause very obscure and difficult-to-track bugs by corrupting a 64-bit value that may be several calling levels above the offending routine. .JSB32_ENTRY should never be used in an AST routine, condition handler, or any other code that can be executed asynchronously. Format .JSB32_ENTRY [input] [,output] [,scratch] [,preserve]
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