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Pankaj Shrivastava
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Joined: 24 Jul 2009
Posts: 51
Location: Pune
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I have a one byte field in the input file . The value could be a hexadecimal from 00 to 99 .
I have to decrement the value by 1 and update the 1 byte field with new value.
What is the most efficient and shortest way of doing it in assembler .Please help with the code. |
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enrico-sorichetti
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Joined: 14 Mar 2007
Posts: 10873
Location: italy
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post what You have devised, and we' ll comment on it
this is a help forum, not a do it for me one  |
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Pankaj Shrivastava
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Joined: 24 Jul 2009
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Ok Enric
This is what i have designed :
SR R5,R5
IC R5,VAR1BYTE
SH R5,=H'1'
STC R5,VAR1BYTE
Your comment please. |
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Bill O'Boyle
CICS Moderator
Joined: 14 Jan 2008
Posts: 2501
Location: Atlanta, Georgia, USA
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Looks OK. You can eliminate the 2-Byte H'1' Literal by using -
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AHI R5,-1 SUBTRACT 1 FROM R5 (CC SET)
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or you can use -
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BCTR R5,0 SUBTRACT 1 FROM R5 (CC NOT SET)
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There isn't any SHI, so using the AHI adding a negative 1 will work.
FWIW, BCTR R0,0 will not work....
Bill |
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Pankaj Shrivastava
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| Thx Bill |
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