What would you want to test for? All I can think of is: Zero result, Not-Zero result, Overflow, Underflow. JZ, JNZ, JO, and ???
On Fri, Mar 15, 2013 at 12:27 PM, Ed Jaffe <[email protected]>wrote: > In the original S/360, nearly all instructions that manipulated binary > integers treated them as signed quantities. (It's the reason that 32K is > a limit in so many places in z/OS e.g., block sizes, number of ASIDs, > etc.) The assembler has a robust implementation of extended mnemonics to > be used after signed arithmetic instructions. > > Recent System z machines have put much more emphasis on unsigned (aka > 'logical') arithmetic. There is now logical load, logical add (with or > without carry), logical subtract (with or without borrow), logical > multiply, logical divide, etc. This technology advance makes sense. In > analyzing our assembler product code, it appears that _at least_ 90% of > our binary integers are eligible for treatment as unsigned values > (counts, offsets, masks, loop control, etc.). Legitimate needs for > signed binary quantities are actually difficult to find! > > Surprisingly, in spite of this hardware instruction paradigm shift, the > assembler still has not yet implemented a set of useful extended > mnemonics for use after unsigned (logical) arithmetic instructions. > Reading PoOp and hard-coding "BRC xx," is an error prone process. I > "smell" a SHARE requirement. In the mean-time, I'm thinking about > writing macros to provide this capability. > > Has anyone thought this through already and come up with what the > mnemonics should be? > > -- > Edward E Jaffe > Phoenix Software International, Inc > 831 Parkview Drive North > El Segundo, CA 90245 > http://www.phoenixsoftware.**com/ <http://www.phoenixsoftware.com/> > -- This is a test of the Emergency Broadcast System. If this had been an actual emergency, do you really think we'd stick around to tell you? Maranatha! <>< John McKown
