The classic dirty trick I saw was a branch 'ladder' where R15 had a return code (must be in multiples of 4!) and the first branch would jump to one of several following branches to real code.
Woe betide if R15 held 3, -1 etc :-) Roops On Sat, 2 Aug 2025 at 22:28, Charles Mills <[email protected]> wrote: > > Did that gain the programmer any advantage over such as TM; BC or was it > entirely theatrical? > > I don't recall at all. > > You can certainly picture some sort of elaborate branch table type logic > dependent on both a condition and an index register in the EX register. > > Charles > > -----Original Message----- > From: IBM Mainframe Assembler List <[email protected]> On > Behalf Of Paul Gilmartin > Sent: Saturday, August 2, 2025 1:27 PM > To: [email protected] > Subject: Re: Execute-Type Instructions > > On 8/2/25 07:54, Charles Mills wrote: > > I think I recall code back in the day that did clever "computed branch" > logic by making a BC or BCR instruction the target of EX. > > > Did that gain the programmer any advantage over such as TM; BC or was it > entirely theatrical? > > > I would defenestrate any programmer that did that sort of thing today. > > > Is the ALTER instruction alive and well in COBOL? > > -- > gil >
