[spec] Documentation of binary format (WebAssembly#17)

Author: binji

document/core/binary/instructions.rst

@@ -126,6 +126,10 @@ Each variant of :ref:`memory instruction <syntax-instr-memory>` is encoded with
 .. _binary-storen:
 .. _binary-memory.size:
 .. _binary-memory.grow:
+.. _binary-memory.init:
+.. _binary-memory.drop:
+.. _binary-memory.copy:
+.. _binary-memory.fill:
 
 .. math::
    \begin{array}{llclll}
@@ -156,11 +160,36 @@ Each variant of :ref:`memory instruction <syntax-instr-memory>` is encoded with
      \hex{3D}~~m{:}\Bmemarg &\Rightarrow& \I64.\STORE\K{16}~m \\ &&|&
      \hex{3E}~~m{:}\Bmemarg &\Rightarrow& \I64.\STORE\K{32}~m \\ &&|&
      \hex{3F}~~\hex{00} &\Rightarrow& \MEMORYSIZE \\ &&|&
-     \hex{40}~~\hex{00} &\Rightarrow& \MEMORYGROW \\
+     \hex{40}~~\hex{00} &\Rightarrow& \MEMORYGROW \\ &&|&
+     \hex{FC}~\hex{08}~~x{:}\Bdataidx &\Rightarrow& \MEMORYINIT~x \\ &&|&
+     \hex{FC}~\hex{09}~~x{:}\Bdataidx &\Rightarrow& \MEMORYDROP~x \\ &&|&
+     \hex{FC}~\hex{0A}~~\hex{00} &\Rightarrow& \MEMORYCOPY \\ &&|&
+     \hex{FC}~\hex{0B}~~\hex{00} &\Rightarrow& \MEMORYFILL \\
    \end{array}
 
 .. note::
-   In future versions of WebAssembly, the additional zero bytes occurring in the encoding of the |MEMORYSIZE| and |MEMORYGROW| instructions may be used to index additional memories.
+   In future versions of WebAssembly, the additional zero bytes occurring in the encoding of the |MEMORYSIZE|, |MEMORYGROW|, |MEMORYCOPY|, and |MEMORYFILL| instructions may be used to index additional memories.
+
+
+Table Instructions
+~~~~~~~~~~~~~~~~~~
+
+Each variant of :ref:`table instruction <syntax-instr-table>` is encoded with a different byte code.
+
+.. _binary-table.init:
+.. _binary-table.drop:
+.. _binary-table.copy:
+
+.. math::
+   \begin{array}{llclll}
+   \production{instruction} & \Binstr &::=& \dots \\ &&|&
+     \hex{FC}~\hex{0C}~~x{:}\Belemidx &\Rightarrow& \TABLEINIT~x \\ &&|&
+     \hex{FC}~\hex{0D}~~x{:}\Belemidx &\Rightarrow& \TABLEDROP~x \\ &&|&
+     \hex{FC}~\hex{0E}~~\hex{00} &\Rightarrow& \TABLECOPY \\
+   \end{array}
+
+.. note::
+   In future versions of WebAssembly, the additional zero byte occurring in the encoding of the |TABLECOPY| instruction may be used to index an additional table.
 
 
 .. index:: numeric instruction

document/core/binary/modules.rst

@@ -9,19 +9,23 @@ except that :ref:`function definitions <syntax-func>` are split into two section
    This separation enables *parallel* and *streaming* compilation of the functions in a module.
 
 
-.. index:: index, type index, function index, table index, memory index, global index, local index, label index
+.. index:: index, type index, function index, table index, memory index, global index, element index, data index, local index, label index
    pair: binary format; type index
    pair: binary format; function index
    pair: binary format; table index
    pair: binary format; memory index
    pair: binary format; global index
+   pair: binary format; element index
+   pair: binary format; data index
    pair: binary format; local index
    pair: binary format; label index
 .. _binary-typeidx:
 .. _binary-funcidx:
 .. _binary-tableidx:
 .. _binary-memidx:
 .. _binary-globalidx:
+.. _binary-elemidx:
+.. _binary-dataidx:
 .. _binary-localidx:
 .. _binary-labelidx:
 .. _binary-index:
@@ -38,6 +42,8 @@ All :ref:`indices <syntax-index>` are encoded with their respective value.
    \production{table index} & \Btableidx &::=& x{:}\Bu32 &\Rightarrow& x \\
    \production{memory index} & \Bmemidx &::=& x{:}\Bu32 &\Rightarrow& x \\
    \production{global index} & \Bglobalidx &::=& x{:}\Bu32 &\Rightarrow& x \\
+   \production{element index} & \Belemidx &::=& x{:}\Bu32 &\Rightarrow& x \\
+   \production{data index} & \Bdataidx &::=& x{:}\Bu32 &\Rightarrow& x \\
    \production{local index} & \Blocalidx &::=& x{:}\Bu32 &\Rightarrow& x \\
    \production{label index} & \Blabelidx &::=& l{:}\Bu32 &\Rightarrow& l \\
    \end{array}
@@ -319,10 +325,18 @@ It decodes into a vector of :ref:`element segments <syntax-elem>` that represent
    \production{element section} & \Belemsec &::=&
      \X{seg}^\ast{:}\Bsection_9(\Bvec(\Belem)) &\Rightarrow& \X{seg} \\
    \production{element segment} & \Belem &::=&
-     x{:}\Btableidx~~e{:}\Bexpr~~y^\ast{:}\Bvec(\Bfuncidx)
-       &\Rightarrow& \{ \ETABLE~x, \EOFFSET~e, \EINIT~y^\ast \} \\
+     \hex{00}~~e{:}\Bexpr~~y^\ast{:}\Bvec(\Bfuncidx)
+       &\Rightarrow& \{ \ETABLE~0, \EOFFSET~e, \EINIT~y^\ast \} \\
+   \production{element segment} & \Belem &::=&
+     \hex{01}~~y^\ast{:}\Bvec(\Bfuncidx)
+       &\Rightarrow& \{ \EINIT~y^\ast \} \\
    \end{array}
 
+.. note::
+   In the current version of WebAssembly, at most one table may be defined or
+   imported in a single module, so all valid :ref:`active <syntax-active>`
+   element segments have a |ETABLE| value of :math:`0`.
+
 
 .. index:: ! code section, function, local, type index, function type
    pair: binary format; function
@@ -400,10 +414,18 @@ It decodes into a vector of :ref:`data segments <syntax-data>` that represent th
    \production{data section} & \Bdatasec &::=&
      \X{seg}^\ast{:}\Bsection_{11}(\Bvec(\Bdata)) &\Rightarrow& \X{seg} \\
    \production{data segment} & \Bdata &::=&
-     x{:}\Bmemidx~~e{:}\Bexpr~~b^\ast{:}\Bvec(\Bbyte)
-       &\Rightarrow& \{ \DMEM~x, \DOFFSET~e, \DINIT~b^\ast \} \\
+     \hex{00}~~e{:}\Bexpr~~b^\ast{:}\Bvec(\Bbyte)
+       &\Rightarrow& \{ \DMEM~0, \DOFFSET~e, \DINIT~b^\ast \} \\
+   \production{data segment} & \Bdata &::=&
+     \hex{01}~~b^\ast{:}\Bvec(\Bbyte)
+       &\Rightarrow& \{ \DINIT~b^\ast \} \\
    \end{array}
 
+.. note::
+   In the current version of WebAssembly, at most one memory may be defined or
+   imported in a single module, so all valid :ref:`active <syntax-active>` data
+   segments have a |DMEM| value of :math:`0`.
+
 
 .. index:: module, section, type definition, function type, function, table, memory, global, element, data, start function, import, export, context, version
    pair: binary format; module

document/core/util/macros.def

@@ -478,6 +478,8 @@
 .. |Btableidx| mathdef:: \xref{binary/modules}{binary-tableidx}{\B{tableidx}}
 .. |Bmemidx| mathdef:: \xref{binary/modules}{binary-memidx}{\B{memidx}}
 .. |Bglobalidx| mathdef:: \xref{binary/modules}{binary-globalidx}{\B{globalidx}}
+.. |Belemidx| mathdef:: \xref{binary/modules}{binary-elemidx}{\B{elemidx}}
+.. |Bdataidx| mathdef:: \xref{binary/modules}{binary-dataidx}{\B{dataidx}}
 .. |Blocalidx| mathdef:: \xref{binary/modules}{binary-localidx}{\B{localidx}}
 .. |Blabelidx| mathdef:: \xref{binary/modules}{binary-labelidx}{\B{labelidx}}