[svn:parrot] r36161 - trunk/docs
rurban at svn.parrot.org
rurban at svn.parrot.org
Thu Jan 29 23:49:15 UTC 2009
Author: rurban
Date: Thu Jan 29 21:28:51 2009
New Revision: 36161
URL: https://trac.parrot.org/parrot/log/branches?rev=36161
Log:
[docs] Update PBC header info in parrotbyte.pod
Modified:
trunk/docs/parrotbyte.pod
Modified: trunk/docs/parrotbyte.pod
==============================================================================
--- trunk/docs/parrotbyte.pod Thu Jan 29 21:09:59 2009 (r36160)
+++ trunk/docs/parrotbyte.pod Thu Jan 29 21:28:51 2009 (r36161)
@@ -7,47 +7,59 @@
=head1 Format of the Parrot bytecode
- 0 1 2 3
+The 18-byte header consists of:
+
+ 0 7
+----------+----------+----------+----------+
- | Wordsize | Byteorder| Major | Minor |
+ | Parrot Magic = 0x 13155a1 |
+----------+----------+----------+----------+
-The wordsize (or C<opcode_t> size) must be 4 (32-bit) or 8 (64 bit). The
+B<Magic> is stored in native byteorder. The loader uses the byteorder header to
+convert the Magic to verify. More specifically, ALL words (non-bytes) in the
+bytecode file are stored in native order, unless otherwise specified.
+
+ 8 9 10 11
+ +----------+----------+----------+
+ | Wordsize | Byteorder| FloatType|
+ +----------+----------+----------+
+
+The B<Wordsize> (or C<opcode_t> size) must be 4 (32-bit) or 8 (64 bit). The
bytecode loader is responsible for transforming the file into the VM native
wordsize on the fly. For performance, a utility F<pdump> is provided to convert
PBCs on disk if they cannot be recompiled. See F<src/pdump.c> for more
information.
-Byteorder currently supports two values: (0-Little Endian, 1-Big Endian)
+B<Byteorder> currently supports two values: (0-Little Endian, 1-Big Endian)
- 4 5
- +----------+----------+----------+----------+
- | INT size | FloatType| 10 Byte ... |
- +----------+----------+----------+----------+
- | fingerprint for ... |
- +----------+----------+----------+----------+
- | core.ops is here |
- +----------+----------+----------+----------+
+B<FloatType> 0 is IEEE 754 8 byte double, FloatType 1 is
+i386 little endian 12 byte long double.
-INT size (sizeof(INTVAL)) must be 4 or 8. FloatType 0 is IEEE 754 8 byte
-double, FloatType 1 is i386 little endian 12 byte long double.
+ 11 12 13 14 15 16
+ +----------+----------+----------+----------+----------+
+ | Major | Minor | Patch | BC Major | BC Minor |
+ +----------+----------+----------+----------+----------+
- 16
- +----------+----------+----------+----------+
- | Parrot Magic = 0x 13155a1 |
- +----------+----------+----------+----------+
+B<Major>, B<Minor>, B<Patch> for the version of Parrot that wrote
+the bytecode file.
-Magic is stored in native byteorder. The loader uses the byteorder header to
-convert the Magic to verify. More specifically, ALL words (non-bytes) in the
-bytecode file are stored in native order, unless otherwise specified.
+B<BC Major> and B<BC Minor> are for the internal bytecode version.
- 20*
+ 16 17 18 19 20 21 22
+ +----------+----------+----------+----------+----------+----------+
+ | UUID type| UUID size| *UUID data |
+ +----------+----------+----------+----------+----------+----------+
+
+After the UUID type and size comes the UUID data pointer.
+
+ 22*
+----------+----------+----------+----------+
- | Opcode Type (Perl = 0x5045524c) |
+ | dir_format (1) |
+ +----------+----------+----------+----------+
+ | padding (0) |
+----------+----------+----------+----------+
-The asterisk for the offset states, from here we have opcodes. The given
-offsets are for 32 bit opcode types only.
+B<dir_format> has length opcode_t and value 1 for PBC FORMAT 1,
+defined in F<packfile.h>
=head1 PBC FORMAT 1
@@ -55,17 +67,8 @@
header and are kept in directories, which itself is a PBC segment. All offsets
and sizes are in native opcodes of the machine that produced the PBC.
-=head2 Format 1 Header
-
- 24*
- +----------+----------+----------+----------+
- | dir_format (1) |
- +----------+----------+----------+----------+
- | padding (0) |
- +----------+----------+----------+----------+
-
-After this header, the first PBC directory follows at offset 32* starting with
-a:
+After the PBC header, the first PBC directory follows at offset 24*
+starting with a:
=head2 Format 1 Segment Header
@@ -172,7 +175,7 @@
=head2 Debug Segment
-The opcode stream will contain one line number per bytecode instruction. No
+The opcode stream will contain one line number per bytecode instruction. No
information as to what file that line is from will be stored in this stream.
The header will start with a count of the number of source file to bytecode
@@ -183,12 +186,12 @@
| number of source => bytecode mappings |
+----------+----------+----------+----------+
-A source to bytecode position mapping simply states that the bytecode that
-starts from the specified offset up until the offset in the next mapping, or
-if there is none up until the end of the bytecode, has it's source in
+A source to bytecode position mapping simply states that the bytecode that
+starts from the specified offset up until the offset in the next mapping, or
+if there is none up until the end of the bytecode, has it's source in
location X.
-A mapping always starts with the offset in the bytecode, followed by the
+A mapping always starts with the offset in the bytecode, followed by the
type of the mapping.
0 (relative)
@@ -203,18 +206,18 @@
There are 3 mapping types.
-Type B<0> means there is no source available for the bytecode starting at the
-given offset. No further data is stored with this type of mapping; the next
+Type B<0> means there is no source available for the bytecode starting at the
+given offset. No further data is stored with this type of mapping; the next
mapping continues immediately after it.
Type B<1> means the source is available in a file. An index into the constants
table follows, which will point to a string containing the filename.
-Type B<2> means the source is available in a source segment. Another integer
+Type B<2> means the source is available in a source segment. Another integer
follows, which will specify which source file in the source segment to use.
-Note that the ordering of the offsets into the bytecode must be sequential;
-a mapping for offset 100 cannot follow a mapping for offset 200, for
+Note that the ordering of the offsets into the bytecode must be sequential;
+a mapping for offset 100 cannot follow a mapping for offset 200, for
example.
=head2 CONSTANT TABLE SEGMENT
@@ -342,7 +345,8 @@
New debug segment format by Jonathan Worthington C<jonathan at jwcs.net>
-=head1 VERSION
+PBC Header updates by Reini Urban C<rurban at x-ray.at>
-2005.10.04
+=head1 VERSION
+2009-01-29
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