/[pcre]/code/trunk/doc/pcrejit.3
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revision 1220 by ph10, Wed Oct 31 17:42:29 2012 UTC revision 1221 by ph10, Sun Nov 11 20:27:03 2012 UTC
# Line 41  JIT. The support is limited to the follo Line 41  JIT. The support is limited to the follo
41    Intel x86 32-bit and 64-bit    Intel x86 32-bit and 64-bit
42    MIPS 32-bit    MIPS 32-bit
43    Power PC 32-bit and 64-bit    Power PC 32-bit and 64-bit
44    SPARC 32-bit (experimental)    SPARC 32-bit (experimental)
45  .sp  .sp
46  If --enable-jit is set on an unsupported platform, compilation fails.  If --enable-jit is set on an unsupported platform, compilation fails.
47  .P  .P
# Line 49  A program that is linked with PCRE 8.20 Line 49  A program that is linked with PCRE 8.20
49  available by calling \fBpcre_config()\fP with the PCRE_CONFIG_JIT option. The  available by calling \fBpcre_config()\fP with the PCRE_CONFIG_JIT option. The
50  result is 1 when JIT is available, and 0 otherwise. However, a simple program  result is 1 when JIT is available, and 0 otherwise. However, a simple program
51  does not need to check this in order to use JIT. The normal API is implemented  does not need to check this in order to use JIT. The normal API is implemented
52  in a way that falls back to the interpretive code if JIT is not available. For  in a way that falls back to the interpretive code if JIT is not available. For
53  programs that need the best possible performance, there is also a "fast path"  programs that need the best possible performance, there is also a "fast path"
54  API that is JIT-specific.  API that is JIT-specific.
55  .P  .P
56  If your program may sometimes be linked with versions of PCRE that are older  If your program may sometimes be linked with versions of PCRE that are older
# Line 387  callback. Line 387  callback.
387  .SH "JIT FAST PATH API"  .SH "JIT FAST PATH API"
388  .rs  .rs
389  .sp  .sp
390  Because the API described above falls back to interpreted execution when JIT is  Because the API described above falls back to interpreted execution when JIT is
391  not available, it is convenient for programs that are written for general use  not available, it is convenient for programs that are written for general use
392  in many environments. However, calling JIT via \fBpcre_exec()\fP does have a  in many environments. However, calling JIT via \fBpcre_exec()\fP does have a
393  performance impact. Programs that are written for use where JIT is known to be  performance impact. Programs that are written for use where JIT is known to be
394  available, and which need the best possible performance, can instead use a  available, and which need the best possible performance, can instead use a
395  "fast path" API to call JIT execution directly instead of calling  "fast path" API to call JIT execution directly instead of calling
396  \fBpcre_exec()\fP (obviously only for patterns that have been successfully  \fBpcre_exec()\fP (obviously only for patterns that have been successfully
397  studied by JIT).  studied by JIT).
398  .P  .P
399  The fast path function is called \fBpcre_jit_exec()\fP, and it takes exactly  The fast path function is called \fBpcre_jit_exec()\fP, and it takes exactly
400  the same arguments as \fBpcre_exec()\fP, plus one additional argument that  the same arguments as \fBpcre_exec()\fP, plus one additional argument that
401  must point to a JIT stack. The JIT stack arrangements described above do not  must point to a JIT stack. The JIT stack arrangements described above do not
402  apply. The return values are the same as for \fBpcre_exec()\fP.  apply. The return values are the same as for \fBpcre_exec()\fP.
403  .P  .P
# Line 408  given. Also, unless PCRE_NO_UTF[8|16|32] Line 408  given. Also, unless PCRE_NO_UTF[8|16|32]
408  for validity. In the interests of speed, these checks do not happen on the JIT  for validity. In the interests of speed, these checks do not happen on the JIT
409  fast path, and if invalid data is passed, the result is undefined.  fast path, and if invalid data is passed, the result is undefined.
410  .P  .P
411  Bypassing the sanity checks and the \fBpcre_exec()\fP wrapping can give  Bypassing the sanity checks and the \fBpcre_exec()\fP wrapping can give
412  speedups of more than 10%.  speedups of more than 10%.
413  .  .
414  .  .
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