Ah, right. 20-bit displacements don't apply to branching instructions.
I've never seen any use of short or long relative addresses that wasn't
consistent, i.e. signed offset in halfwords.
sas
On Fri, Nov 10, 2023 at 8:13 AM Seymour J Metz wrote:
> I'm not aware of any branch instructions
From: IBM Mainframe Assembler List on behalf
of Steve Smith
Sent: Friday, November 10, 2023 12:22 AM
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Re: Based vs. Relative (was: Internal Exit Routine Handling)
You forgot the 4th, 20-bit based signed displacement
You forgot the 4th, 20-bit based signed displacement (Y & G-suffixed
instructions). Just to have a chance at misremembering, I think that's
about +/- half a MB.
sas
On Thu, Nov 9, 2023 at 1:33 PM Seymour J Metz wrote:
> There are only three sizes:
>
> legacy, 12 bits, unsigned, 4 Ki byts
>
From: IBM Mainframe Assembler List on behalf
of Dave Clark
Sent: Thursday, November 9, 2023 12:54 PM
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Re: Based vs. Relative (was: Internal Exit Routine Handling)
"IBM Mainframe Assembler List" wrote on
11/09/2023 12:33:58 PM:
&g
On Thu, 9 Nov 2023 12:54:36 -0500, Dave Clark wrote:
>"IBM Mainframe Assembler List" wrote on
>11/09/2023 12:33:58 PM:
>> Principles is your friend!
>
>Yes, I will be doing some reading. But a few quick answers are
>helpful.
>
Please do. It isn't that hard to look up one instruction
"IBM Mainframe Assembler List" wrote on
11/09/2023 12:54:36 PM:
> > But in addition to up to 4K, you can actually
> > do up to +/- 65K.
> OK, so the "normal" relative jump is the signed, 16-bit variety
> mentioned (15-bit relative target with left-most bit as the direction).
> How is
"IBM Mainframe Assembler List" wrote on
11/09/2023 12:53:26 PM:
> I would personally find
> If condition
> Then
> 200 lines of code
> Else
> 150 lines of code
> End-if
> hard to navigate.
I don't disagree with you. But if you allow someone to do a
"IBM Mainframe Assembler List" wrote on
11/09/2023 12:33:58 PM:
> Principles is your friend!
Yes, I will be doing some reading. But a few quick answers are
helpful.
> But in addition to up to 4K, you can actually
> do up to +/- 65K.
OK, so the "normal" relative jump is the
hone and delete the original message from your
mail system.
From: IBM Mainframe Assembler List on behalf
of Charles Mills
Sent: November 9, 2023 12:33
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Re: Based vs. Relative (was: Internal Exit Routine Handling)
Princi
ame Assembler List [mailto:ASSEMBLER-LIST@LISTSERV.UGA.EDU]
On Behalf Of Dave Clark
Sent: Thursday, November 9, 2023 9:17 AM
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Based vs. Relative (was: Internal Exit Routine Handling)
"IBM Mainframe Assembler List" wrote on
11/09/2023 11:27:
: IBM Mainframe Assembler List on behalf
of Dave Clark
Sent: Thursday, November 9, 2023 12:16 PM
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: Based vs. Relative (was: Internal Exit Routine Handling)
"IBM Mainframe Assembler List" wrote on
11/09/2023 11:27:20 AM:
> IMHO, relati
"IBM Mainframe Assembler List" wrote on
11/09/2023 11:27:20 AM:
> IMHO, relative branch use is a "best practice" in all situations. I
> *never* use a based branch if an equivalent relative branch will
suffice...
I've been coding based-branches since 1980 and never moved on to
the
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