Hi Guys,
Specifically to Dave Cole's query...
>>>(FWIW, I find both books to be abysmal documents!)
>>>(There. That ought to create a firestorm!)
A few years ago and on this forum I dared to say that the PoO was
totally inadequate for the 21st century...an opinion I still hold
It did get a 'firestorm' reaction, about evenly distributed between,
"it's a bible and cannot be modified" to those agreeing with me
Among my suggestions, only applying to instruction descriptions is that...
These should be in a separate Manual, one 'page' per instruction,
hyperlinks to similar instructions, maybe a tracker saying 'people who
looked at AHI also looked at LHI :-)'
Perhaps there's someone out there who has the time
Melvyn Maltz.
On 10/02/2022 07:40 pm, David Cole wrote:
WRT:
"A gentle reminder on terminology: The term "JUMP" appears neither in
the PoO nor in the z/Architecture Reference Summary (SA22-7832). What
you refer to as "JAS (jump and save)" is simply reflecting the
extended mnemonic for BRANCH RELATIVE AND SAVE (BRAS)."
The PoOps has some inconsistencies... One that I find rather
irritating is the presences of extended mnemonics for a large number
of newer instructions, but the omission of same for all of the BC,
BRC, BRAS and related instructions.
Yes, I am quite aware that I included redundant entries in my list. I
didn't care because it was beside the point.
Speaking of fake mnemonics... What is the difference between "extended
mnemonics" (such as CGIJNE) and "alternative mnemonics" (such as JAS)?
Is it that one is documented only in the PoOp and the other only in
HLASM Ref?
(FWIW, I find both books to be abysmal documents!)
(There. That ought to create a firestorm!)
Dave
At 2/10/2022 01:27 PM, Dan Greiner wrote:
Having learned this stuff in the 1970s — before the linkage stack
showed up in the late 1980s — I was accustomed to hearing them called
simply "linkage instructions." For the common usage of application
programmers who need a simple instruction to branch to Oz while
leaving a footprint of how to get back to Kansas, that's probably
sufficient.
.
The z/Architecture Principles of Operation (SA22-7832-10) refers to
such instruction in a section labelled "Subroutine Linkage without
the Linkage Stack" (p. 5-16 onward), with the simple stuff like
BAL[R], BAS[R] and friends called "Simple Branch Instructions". This
text shows the awkwardness that crept into the architecture when
various commonly-used terms get redeployed for other purposes. [A
brief aside: During the design of the S/360, the designers
deliberately eschewed a stack architecture in favor of the chained
save-area approach. With the advent of ESA, they changed their minds
(sort of) and implemented a linkage stack.]
A gentle reminder on terminology: The term "JUMP" appears neither in
the PoO nor in the z/Architecture Reference Summary (SA22-7832). What
you refer to as "JAS (jump and save)" is simply reflecting the
extended mnemonic for BRANCH RELATIVE AND SAVE (BRAS).
