ALSIHN - Add Logical With Signed Immediate High

But I can't think of why it exists. ALSIH also exists which performs the
exact same operation, but does set the CC.

ALSIHN Rx,I

Bits 0..31 of Rx are considered an unsigned 32 bit integer. I is a 32
bit signed integer. Bits 32..63 of Rx are undisturbed.

Do __you__ know why? I assume the C compiler writers asked for it for
some reason. Likely a multi-instruction sequence where a branch of some
sort is done after the ALSIHN but needs the CC of the previous
instruction. I just can't think of the need.


..some instruction which sets the CC..
ALSIHN ????
..branch based on CC of instruction before ALSIHN

Or maybe it's more complicated than that.

On Sat, 2010-12-11 at 10:13 -0500, Don Higgins wrote:
> As I'm finishing up adding all the new z196 instructions to the z390
> Portable Mainframe Assembler and Emulator for Windows and Linux, I've come
> across a single ADD instruction which does not set the condition code.
> What is it and why was it added?
>
> Don Higgins
> [email protected]
--
John McKown
Maranatha! <><

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