man21 - 11/3/71 NAME SYNOPSIS DESCRIPTION break - set...

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11/3/71 SYS BREAK (II) NAME break -- set program break SYNOPSIS sys break; addr / break = 17. DESCRIPTION break sets the system’s idea of the highest location used by the program to addr. Locations greater than addr and below the stack pointer are not swapped and are thus liable to unexpected modification. If the argument is 0 or higher than the stack pointer the entire 4K word user core area is swapped. When a program begins execution via exec the break is set, at the highest location defined by the program and data storage areas. Ordinarily, therefore, only programs with growing data areas need to use break. FILES SEE ALSO exec DIAGNOSTICS none; strange addresses cause the break to be set to include all of core. BUGS OWNER ken, dmr
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11/3/71 SYS CEMT (II) NAME cemt -- catch emt traps SYNOPSIS sys cemt; arg / cemt = 29.; not in assembler DESCRIPTION This call allows one to catch traps resulting from the emt instruction. Arg is a location within the program; emt traps are sent to that location. The normal effect of emt traps may be restored by giving an arg equal to 0. Prior to the use of this call, the result of an emt instruction is a simulated rts instruction. The operand field is interpreted as a register, and an rts instruction is simulated for that register (after verifying that various registers have appropriate values). This feature is useful for debugging, since the most dangerous program bugs usually involve an rts with bad data on the stack or in a register. FILES SEE ALSO DIAGNOSTICS BUGS OWNER ken, dmr
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11/3/71 SYS CHDIR (II) NAME chdir -- change working directory SYNOPSIS sys chdir; dirname / chdir = 12. DESCRIPTION dirname is address of the pathname of a directory, terminated by a 0 byte. chdir causes this directory to become the current working directory. FILES SEE ALSO DIAGNOSTICS The error bit (c—bit) is set if the given name is not that of a directory. BUGS OWNER ken, dmr
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SYS CHMOD (II) NAME chmod -- change mode of file SYNOPSIS sys chmod; name; mode / chmod = 15. DESCRIPTION The file whose name is given as the null—terminated string pointed to by name has its mode changed to mode. Modes are constructed by oring together some combination of the following: 01 write, non—owner 02 read, non—owner 04 write, owner 10 read, owner 20 executable 40 set user ID on execution Only the owner of a file (or the super—user) may change the mode. FILES SEE ALSO DIAGNOSTICS Error bit (c—bit) set if name cannot be found or if current user is neither the owner of the file nor the super—user. BUGS
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This note was uploaded on 04/18/2010 for the course ARCH Arch 101 taught by Professor Edwardhoe during the Spring '10 term at 카이스트, 한국과학기술원.

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man21 - 11/3/71 NAME SYNOPSIS DESCRIPTION break - set...

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