glenda.party
term% ls -F
term% pwd
$home/manuals/plan9_2nd/1/vi
term% cat index.txt
VI(1)                       General Commands Manual                      VI(1)



NAME
       vi, ki, xi - instruction simulators

SYNOPSIS
       vi [ textfile ]
       vi pid
       ki [ textfile ]
       ki pid
       xi [ textfile ]
       xi pid

DESCRIPTION
       Vi  simulates  the  execution of a MIPS binary in a Plan 9 environment.
       It has two main uses: as a debugger and as a statistics gatherer.  Pro‐
       grams running under vi execute about two hundred times slower than nor‐
       mal—but faster than single stepping under db.  Ki and xi are similar to
       vi  but interpret SPARC and ATT3210 binaries.  The following discussion
       refers to vi but applies to the others as well.

       Vi will simulate the execution of a named textfile.  It will also  make
       a copy of an existing process with process id pid and simulate its con‐
       tinuation.

       As a debugger vi offers more complete information than db(1).   Tracing
       can  be  performed at the level of instructions, system calls, or func‐
       tion calls.  Vi allows breakpoints to be triggered when  specified  ad‐
       dresses  in  memory are accessed.  A report of instruction counts, load
       delay fills and distribution is produced for each  run.   Vi  simulates
       the  CPU's  caches  and MMU to assist the optimization of compilers and
       programs.

       The command interface mirrors the interface to db; see db(1) for a  de‐
       tailed description.  Data formats and addressing are compatible with db
       except for disassembly: vi offers only MIPS (db -mmipsco) mnemonics for
       machine instructions.  Ki offers both Plan 9 and Sun SPARC formats.

       Several  extra  commands allow extended tracing and printing of statis‐
       tics:

       $t[0ics]
              The t command controls tracing. Zero  cancels  all  tracing  op‐
              tions.

              i      Enable instruction tracing

              c      Enable call tracing

              s      Enable system call tracing

       $i[itsp]
              The  i  command prints statistics accumulated by all code run in
              this session.

              i      Print instruction counts and frequency.

              p      Print cycle profile.

              t      (Vi only) Print TLB and cache statistics.

              s      Print memory reference, working set and size statistics.

       :b[arwe]
              Vi allows breakpoints to be set on any memory  location.   These
              breakpoints  monitor when a location is accessed, read, written,
              or equals a certain value.  For equality the compared  value  is
              the count (see db(1)) supplied to the command.

SOURCE
       /sys/src/cmd/vi etc.

SEE ALSO
       nm(1), db(1)

BUGS
       The code generated by the compilers is well supported, but some unusual
       instructions are unimplemented.  Some Plan 9 system calls such as rfork
       cause simulated traps.  The floating point simulation makes assumptions
       about the interpreting machine's floating point support.  The  floating
       point conversions performed by vi may cause a loss of precision.



                                                                         VI(1)