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jzhardy
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Joined: 31 Oct 2006
Posts: 139
Location: brisbane
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New to HLASM so this may seem a like dumb question, but I couldn't find any answer on google, and the answer from Chat GPT has left me perplexed.
Most commonly I see STM with a displacement of 12, such as:
STM 13,12,12(13)
according to Chat GPT, it's a convention used to force full word alignment, but I can't see how it does that since R13 is set by the caller ... in any case, surely, it's the responsibility of the calling program to establish a save area that is aligned on full words ? |
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jzhardy
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Joined: 31 Oct 2006
Posts: 139
Location: brisbane
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| i think i see it now ... we use the first part of the save area to maintain forward and backward pointers to save areas... |
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Willy Jensen
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Joined: 01 Sep 2015
Posts: 730
Location: Denmark
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Actually, according to the convention, the first 3 words (=12 bytes) are used as follows
word 1 used to be reserved for PL/1, but is now often used to specify the type of save area, I cant' immediately recall what the specifications are, but I am sure that others can.
word 2 point to previous save area
word 3 point to next save area |
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Willy Jensen
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Location: Denmark
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