From: Philipp K. K. <pk...@sp...> - 2014-02-09 08:32:36
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Am 09.02.2014 04:33, schrieb Ben Shi: > Hello, here are their definition > > bitVect *rMask; /* registers in use during this > instruction */ bitVect *rSurv; /* registers that > survive this instruction (i.e. they are in use, it is not their > last use and they are not in the return) */ It seems both of them > indicate regs are keeping values, but what is the difference? Can > somebody show me an example to distinguish? > > Ben They survive, if they need to keep their value: The value after the instruction in the register should be the same af before. For a register that is in use during the instruction this is not true: It might hold a value that is written during the instruction. Assume for example We have one value in register x and one in y at the instruction that adds the value in x to the value in y. And there are further uses for the value in y. In this case both x and y are in use at the instruction. y survives, but y does not. Philipp -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iEYEARECAAYFAlL3PRQACgkQbtUV+xsoLpqudwCgqoj8/lZXIodKvQaDvXEHUlET Q44AoK2APqONxFPNVw73UA/EY4H9w7Tm =j9A1 -----END PGP SIGNATURE----- |