On Thu, Jun 20, 2019 at 8:40 AM Charles Mills <[email protected]> wrote:
> IMHO a lot of the z/OS API ("assembler services") documentation is unclear
> on level of indirection. You often have to really parse the wording to
> determine if CODE=(R2) means the code is *in* R2, or in a word that R2
> points to.
>
> That said, I think that while the wording in PoOp might be clearer, it
> seems clear to me. The key phrase is "operand _in storage_." I have trouble
> interpreting that any way except "the doubleword at the operand address
> contains the branch address." Also, given the word "Indirect" in the name I
> have trouble guessing it would be otherwise.
>
I see your point. No RCF needed. Thanks.
>
> Charles
>
>
> -----Original Message-----
> From: IBM Mainframe Assembler List [mailto:[email protected]]
> On Behalf Of John McKown
> Sent: Thursday, June 20, 2019 6:01 AM
> To: [email protected]
> Subject: BIC documentation - unclear?
>
> I am continuing my "education" in the newer instructions. I think that I
> understand what Branch Indirect on Condition (BIC) does. Instead of
> branching to the address in the instruction, it fetches the 8 bytes at that
> address and uses that as the branch address, respecting the AMODE of
> course. But the documentation seems unclear to me. It is on page 7-39 of
> SA22-7832-11
>
>
>
>
>
>
>
> *The eight-byte second operand in storage is used asthe branch address. The
> branch address is subject tothe current addressing mode. All eight bytes of
> thesecond operand are accessed, regardless of theaddressing mode.*
>
>
> I am thinking that it should explicitly state that the second operand
> _contains_ the address to be branched to. Unless, of course, I am totally
> misunderstanding what the instruction does. E.g.
>
> *The eight-byte second operand in storage contains **the branch address.
> The branch address is subject to **the current addressing mode. All eight
> bytes of the **second operand are accessed, regardless of the **addressing
> mode.*
>
> or perhaps
>
>
>
>
>
> *The contents of the eight-byte second operand in storage is used asthe
> branch address. The branch address is subject tothe current addressing
> mode. All eight bytes of thesecond operand are accessed, regardless of the*
> *addressing mode.*
>
> RCF?
>
--
Money is the root of all evil.
Evil is the root of all money.
With that in mind, money is made by the government ...
Maranatha! <><
John McKown
