flat assembler
Message board for the users of flat assembler.
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Tomasz Grysztar 23 Sep 2008, 14:22
Since you already know BT, read also about BTS/BTR/BTC.
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asmcoder 23 Sep 2008, 14:47
[content deleted]
Last edited by asmcoder on 14 Aug 2009, 14:56; edited 1 time in total |
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bitRAKE 23 Sep 2008, 15:25
All BT/BTC/BTS/BTR put the bit value in the carry flag - this is the "test". There is no single instruction to swap the carry flag and another bit. IIRC, there is a binary math trick to swap bits requiring two instructions, but no branch.
_________________ ¯\(°_o)/¯ The hardcore cynic mistakes good for guile. |
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edfed 23 Sep 2008, 16:57
no, that means complement.
com1=0 com0=1 and this subject is still aborded on the board many times. |
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baldr 09 Oct 2008, 19:14
asmcoder,
How about good old or [a],1? ![]() btx family is good for bit manipulation at an arbitrary bit index (they support register operand as bit index), for fixed bit index test, and, or & xor are somewhat better (proper coding ensures that you won't access word[0xFFFF] in 16-bit RM ![]() By the way, IA-32 (2003 A.D.) and Intel® 64 (April 2008, maybe 1st ![]() |
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