Even though it may not happen often the EQU can point to an odd address
and cause the label to be referenced when it is filled with binary zeroes (S0C1)
The use of 0H always forces boundary alignment for instructions
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On Mon, Jun 1, 2020 at 1:43 PM -0700, "Schmitt, Michael"
<michael.schm...@dxc.com> wrote:
In John R. Ehrman's SHARE presentations on tips for modernizing IBM
z/Architecture assembler programs (such as
https://share.confex.com/share/120/webprogram/Handout/Session12522/modrnasm.pdf),
he says that important advice from experienced assembler programmers is to:
_Don't_ use EQU for statement-label creation
Can anyone venture a guess as to the reason for this advice? I've been coding
MVS assembler for 30 years and this is the first I've heard of this guideline.
One thing I'm wondering is if the suggestion is to avoid stand alone statement
labels entirely (such as LABEL EQU * or LABEL DS 0H) in favor of putting the
label on the next instruction? Or is there something about EQU * that makes it
a bad alternative to DS 0H?
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Michael Schmitt | DXC.technology
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