'\" '\" Generated from file 'gasm\&.man' by tcllib/doctools with format 'nroff' '\" Copyright (c) 2005 Andreas Kupries '\" .TH "grammar::me::cpu::gasm" 3tcl 0\&.1 tcllib "Grammar operations and usage" .\" The -*- nroff -*- definitions below are for supplemental macros used .\" in Tcl/Tk manual entries. .\" .\" .AP type name in/out ?indent? .\" Start paragraph describing an argument to a library procedure. .\" type is type of argument (int, etc.), in/out is either "in", "out", .\" or "in/out" to describe whether procedure reads or modifies arg, .\" and indent is equivalent to second arg of .IP (shouldn't ever be .\" needed; use .AS below instead) .\" .\" .AS ?type? ?name? .\" Give maximum sizes of arguments for setting tab stops. Type and .\" name are examples of largest possible arguments that will be passed .\" to .AP later. If args are omitted, default tab stops are used. .\" .\" .BS .\" Start box enclosure. From here until next .BE, everything will be .\" enclosed in one large box. .\" .\" .BE .\" End of box enclosure. .\" .\" .CS .\" Begin code excerpt. .\" .\" .CE .\" End code excerpt. .\" .\" .VS ?version? ?br? .\" Begin vertical sidebar, for use in marking newly-changed parts .\" of man pages. The first argument is ignored and used for recording .\" the version when the .VS was added, so that the sidebars can be .\" found and removed when they reach a certain age. If another argument .\" is present, then a line break is forced before starting the sidebar. .\" .\" .VE .\" End of vertical sidebar. .\" .\" .DS .\" Begin an indented unfilled display. .\" .\" .DE .\" End of indented unfilled display. .\" .\" .SO ?manpage? .\" Start of list of standard options for a Tk widget. The manpage .\" argument defines where to look up the standard options; if .\" omitted, defaults to "options". The options follow on successive .\" lines, in three columns separated by tabs. .\" .\" .SE .\" End of list of standard options for a Tk widget. .\" .\" .OP cmdName dbName dbClass .\" Start of description of a specific option. cmdName gives the .\" option's name as specified in the class command, dbName gives .\" the option's name in the option database, and dbClass gives .\" the option's class in the option database. .\" .\" .UL arg1 arg2 .\" Print arg1 underlined, then print arg2 normally. .\" .\" .QW arg1 ?arg2? .\" Print arg1 in quotes, then arg2 normally (for trailing punctuation). .\" .\" .PQ arg1 ?arg2? .\" Print an open parenthesis, arg1 in quotes, then arg2 normally .\" (for trailing punctuation) and then a closing parenthesis. .\" .\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b .\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ta \\n()Au \\n()Bu .ie !"\\$3"" \{\ \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. .\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out .\" # BS - start boxed text .\" # ^y = starting y location .\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. .\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. .\" # VS - start vertical sidebar .\" # ^Y = starting y location .\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$2"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. .\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. .\" # Special macro to handle page bottom: finish off current .\" # box/sidebar if in box/sidebar mode, then invoked standard .\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. .\" # DS - begin display .de DS .RS .nf .sp .. .\" # DE - end display .de DE .fi .RE .sp .. .\" # SO - start of list of standard options .de SO 'ie '\\$1'' .ds So \\fBoptions\\fR 'el .ds So \\fB\\$1\\fR .SH "STANDARD OPTIONS" .LP .nf .ta 5.5c 11c .ft B .. .\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\*(So manual entry for details on the standard options. .. .\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. .\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. .\" # CE - end code excerpt .de CE .fi .RE .. .\" # UL - underline word .de UL \\$1\l'|0\(ul'\\$2 .. .\" # QW - apply quotation marks to word .de QW .ie '\\*(lq'"' ``\\$1''\\$2 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\$2 .. .\" # PQ - apply parens and quotation marks to word .de PQ .ie '\\*(lq'"' (``\\$1''\\$2)\\$3 .\"" fix emacs highlighting .el (\\*(lq\\$1\\*(rq\\$2)\\$3 .. .\" # QR - quoted range .de QR .ie '\\*(lq'"' ``\\$1''\\-``\\$2''\\$3 .\"" fix emacs highlighting .el \\*(lq\\$1\\*(rq\\-\\*(lq\\$2\\*(rq\\$3 .. .\" # MT - "empty" string .de MT .QW "" .. .BS .SH NAME grammar::me::cpu::gasm \- ME assembler .SH SYNOPSIS package require \fBgrammar::me::cpu::gasm ?0\&.1?\fR .sp \fB::grammar::me::cpu::gasm::begin\fR \fIg\fR \fIn\fR ?\fImode\fR? ?\fInote\fR? .sp \fB::grammar::me::cpu::gasm::done\fR \fB-->\fR \fIt\fR .sp \fB::grammar::me::cpu::gasm::state\fR .sp \fB::grammar::me::cpu::gasm::state!\fR \fIs\fR .sp \fB::grammar::me::cpu::gasm::lift\fR \fIt\fR \fIdst\fR \fB=\fR \fIsrc\fR .sp \fB::grammar::me::cpu::gasm::Inline\fR \fIt\fR \fInode\fR \fIlabel\fR .sp \fB::grammar::me::cpu::gasm::Cmd\fR \fIcmd\fR ?\fIarg\fR\&.\&.\&.? .sp \fB::grammar::me::cpu::gasm::Bra\fR .sp \fB::grammar::me::cpu::gasm::Nop\fR \fItext\fR .sp \fB::grammar::me::cpu::gasm::Note\fR \fItext\fR .sp \fB::grammar::me::cpu::gasm::Jmp\fR \fIlabel\fR .sp \fB::grammar::me::cpu::gasm::Exit\fR .sp \fB::grammar::me::cpu::gasm::Who\fR \fIlabel\fR .sp \fB::grammar::me::cpu::gasm::/Label\fR \fIname\fR .sp \fB::grammar::me::cpu::gasm::/Clear\fR .sp \fB::grammar::me::cpu::gasm::/Ok\fR .sp \fB::grammar::me::cpu::gasm::/Fail\fR .sp \fB::grammar::me::cpu::gasm::/At\fR \fIname\fR .sp \fB::grammar::me::cpu::gasm::/CloseLoop\fR .sp .BE .SH DESCRIPTION This package provides a simple in-memory assembler\&. Its origin is that of a support package for use by packages converting PEG and other grammars into a corresponding matcher based on the ME virtual machine, like \fBpage::compiler::peg::mecpu\fR\&. Despite that it is actually mostly agnostic regarding the instructions, users can choose any instruction set they like\&. .PP The program under construction is held in a graph structure (See package \fBstruct::graph\fR) during assembly and subsequent manipulation, with instructions represented by nodes, and the flow of execution between instructions explicitly encoded in the arcs between them\&. .PP In this model jumps are not encoded explicitly, they are implicit in the arcs\&. The generation of explicit jumps is left to any code converting the graph structure into a more conventional representation\&. The same goes for branches\&. They are implicitly encoded by all instructions which have two outgoing arcs, whereas all other instructions have only one outgoing arc\&. Their conditonality is handled by tagging their outgoing arcs with information about the conditions under which they are taken\&. .PP While the graph the assembler operates on is supplied from the outside, i\&.e\&. external, it does manage some internal state, namely: .IP [1] The handle of the graph node most assembler operations will work on, the \fIanchor\fR\&. .IP [2] A mapping from arbitrary strings to instructions\&. I\&.e\&. it is possible to \fIlabel\fR an instruction during assembly, and later recall that instruction by its label\&. .IP [3] The condition code to use when creating arcs between instructions, which is one of \fBalways\fR, \fBok\fR, and \fBfail\fR\&. .IP [4] The current operation mode, one of \fBhalt\fR, \fBokfail\fR, and \fB!okfail\fR\&. .IP [5] The name of a node in a tree\&. This, and the operation mode above are the parts most heavily influenced by the needs of a grammar compiler, as they assume some basic program structures (selected through the operation mode), and intertwine the graph with a tree, like the AST for the grammar to be compiled\&. .PP .SH DEFINITIONS As the graph the assembler is operating on, and the tree it is intertwined with, are supplied to the assembler from the outside it is necessary to specify the API expected from them, and to describe the structures expected and/or generated by the assembler in either\&. .PP .IP [1] Any graph object command used by the assembler has to provide the API as specified in the documentation for the package \fBstruct::graph\fR\&. .IP [2] Any tree object command used by the assembler has to provide the API as specified in the documentation for the package \fBstruct::tree\fR\&. .IP [3] Any instruction (node) generated by the assembler in a graph will have at least two, and at most three attributes: .RS .TP \fBinstruction\fR The value of this attribute is the name of the instruction\&. The only names currently defined by the assembler are the three pseudo-instructions .RS .TP \fBNOP\fR This instruction does nothing\&. Useful for fixed framework nodes, unchanging jump destinations, and the like\&. No arguments\&. .TP \fBC\fR A \&.NOP to allow the insertion of arbitrary comments into the instruction stream, i\&.e\&. a comment node\&. One argument, the text of the comment\&. .TP \fBBRA\fR A \&.NOP serving as explicitly coded conditional branch\&. No arguments\&. .RE .IP However we reserve the space of all instructions whose names begin with a "\&." (dot) for future use by the assembler\&. .TP \fBarguments\fR The value of this attribute is a list of strings, the arguments of the instruction\&. The contents are dependent on the actual instruction and the assembler doesn't know or care about them\&. This means for example that it has no builtin knowledge about what instruction need which arguments and thus doesn't perform any type of checking\&. .TP \fBexpr\fR This attribute is optional\&. When it is present its value is the name of a node in the tree intertwined with the graph\&. .RE .IP [4] Any arc between two instructions will have one attribute: .RS .TP \fBcondition\fR The value of this attribute determines under which condition execution will take this arc\&. It is one of \fBalways\fR, \fBok\fR, and \fBfail\fR\&. The first condition is used for all arcs which are the single outgoing arc of an instruction\&. The other two are used for the two outgoing arcs of an instruction which implicitly encode a branch\&. .RE .IP [5] A tree node given to the assembler for cross-referencing will be written to and given the following attributes, some fixed, some dependent on the operation mode\&. All values will be references to nodes in the instruction graph\&. Some of the instruction will expect some or specific sets of these attributes\&. .RS .TP \fBgas::entry\fR Always written\&. .TP \fBgas::exit\fR Written for all modes but \fBokfail\fR\&. .TP \fBgas::exit::ok\fR Written for mode \fBokfail\fR\&. .TP \fBgas::exit::fail\fR Written for mode \fBokfail\fR\&. .RE .PP .SH API .TP \fB::grammar::me::cpu::gasm::begin\fR \fIg\fR \fIn\fR ?\fImode\fR? ?\fInote\fR? This command starts the assembly of an instruction sequence, and (re)initializes the state of the assembler\&. After completion of the instruction sequence use \fB::grammar::me::cpu::gasm::done\fR to finalize the assembler\&. .sp It will operate on the graph \fIg\fR in the specified \fImode\fR (Default is \fBokfail\fR)\&. As part of the initialization it will always create a standard \&.NOP instruction and label it "entry"\&. The creation of the remaining standard instructions is \fImode\fR-dependent: .RS .TP \fBhalt\fR An "icf_halt" instruction labeled "exit/return"\&. .TP \fB!okfail\fR An "icf_ntreturn" instruction labeled "exit/return"\&. .TP \fBokfail\fR Two \&.NOP instructions labeled "exit/ok" and "exit/fail" respectively\&. .RE .IP The \fInote\fR, if specified (default is not), is given to the "entry" \&.NOP instruction\&. .sp The node reference \fIn\fR is simply stored for use by \fB::grammar::me::cpu::gasm::done\fR\&. It has to refer to a node in the tree \fIt\fR argument of that command\&. .sp After the initialization is done the "entry" instruction will be the \fIanchor\fR, and the condition code will be set to \fBalways\fR\&. .sp The command returns the empy string as its result\&. .TP \fB::grammar::me::cpu::gasm::done\fR \fB-->\fR \fIt\fR This command finalizes the creation of an instruction sequence and then clears the state of the assembler\&. \fINOTE\fR that this \fIdoes not\fR delete any of the created instructions\&. They can be made available to future begin/done cycles\&. Further assembly will be possible only after reinitialization of the system via \fB::grammar::me::cpu::gasm::begin\fR\&. .sp Before the state is cleared selected references to selected instructions will be written to attributes of the node \fIn\fR in the tree \fIt\fR\&. Which instructions are saved is \fImode\fR-dependent\&. Both \fImode\fR and the destination node \fIn\fR were specified during invokation of \fB::grammar::me::cpu::gasm::begin\fR\&. .sp Independent of the mode a reference to the instruction labeled "entry" will be saved to the attribute \fBgas::entry\fR of \fIn\fR\&. The reference to the node \fIn\fR will further be saved into the attribute "expr" of the "entry" instruction\&. Beyond that .RS .TP \fBhalt\fR A reference to the instruction labeled "exit/return" will be saved to the attribute \fBgas::exit\fR of \fIn\fR\&. .TP \fBokfail\fR See \fBhalt\fR\&. .TP \fB!okfail\fR Reference to the two instructions labeled "exit/ok" and "exit/fail" will be saved to the attributes \fBgas::exit::ok\fR and \fBgas::exit::fail\fR of \fIn\fR respectively\&. .RE .sp The command returns the empy string as its result\&. .TP \fB::grammar::me::cpu::gasm::state\fR This command returns the current state of the assembler\&. Its format is not documented and considered to be internal to the package\&. .TP \fB::grammar::me::cpu::gasm::state!\fR \fIs\fR This command takes a serialized assembler state \fIs\fR as returned by \fB::grammar::me::cpu::gasm::state\fR and makes it the current state of the assembler\&. .sp \fINote\fR that this may overwrite label definitions, however all non-conflicting label definitions in the state before are not touched and merged with \fIs\fR\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::lift\fR \fIt\fR \fIdst\fR \fB=\fR \fIsrc\fR This command operates on the tree \fIt\fR\&. It copies the contents of the attributes \fBgas::entry\fR, \fBgas::exit::ok\fR and \fBgas::exit::fail\fR from the node \fIsrc\fR to the node \fIdst\fR\&. It returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::Inline\fR \fIt\fR \fInode\fR \fIlabel\fR This command links an instruction sequence created by an earlier begin/done pair into the current instruction sequence\&. .sp To this end it .RS .IP [1] reads the instruction references from the attributes \fBgas::entry\fR, \fBgas::exit::ok\fR, and \fBgas::exit::fail\fR from the node \fIn\fR of the tree \fIt\fR and makes them available to assembler und the labels \fIlabel\fR/entry, \fIlabel\fR/exit::ok, and \fIlabel\fR/exit::fail respectively\&. .IP [2] Creates an arc from the \fIanchor\fR to the node labeled \fIlabel\fR/entry, and tags it with the current condition code\&. .IP [3] Makes the node labeled \fIlabel\fR/exit/ok the new \fIanchor\fR\&. .RE .IP The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::Cmd\fR \fIcmd\fR ?\fIarg\fR\&.\&.\&.? This is the basic command to add instructions to the graph\&. It creates a new instruction of type \fIcmd\fR with the given arguments \fIarg\fR\&.\&.\&. If the \fIanchor\fR was defined it will also create an arc from the \fIanchor\fR to the new instruction using the current condition code\&. After the call the new instruction will be the \fIanchor\fR and the current condition code will be set to \fBalways\fR\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::Bra\fR This is a convenience command to create a \&.BRA pseudo-instruction\&. It uses \fB::grammar::me::cpu::gasm::Cmd\fR to actually create the instruction and inherits its behaviour\&. .TP \fB::grammar::me::cpu::gasm::Nop\fR \fItext\fR This is a convenience command to create a \&.NOP pseudo-instruction\&. It uses \fB::grammar::me::cpu::gasm::Cmd\fR to actually create the instruction and inherits its behaviour\&. The \fItext\fR will be saved as the first and only argument of the new instruction\&. .TP \fB::grammar::me::cpu::gasm::Note\fR \fItext\fR This is a convenience command to create a \&.C pseudo-instruction, i\&.e\&. a comment\&. It uses \fB::grammar::me::cpu::gasm::Cmd\fR to actually create the instruction and inherits its behaviour\&. The \fItext\fR will be saved as the first and only argument of the new instruction\&. .TP \fB::grammar::me::cpu::gasm::Jmp\fR \fIlabel\fR This command creates an arc from the \fIanchor\fR to the instruction labeled with \fIlabel\fR, and tags with the the current condition code\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::Exit\fR This command creates an arc from the \fIanchor\fR to one of the exit instructions, based on the operation mode (see \fB::grammar::me::cpu::gasm::begin\fR), and tags it with current condition code\&. .sp For mode \fBokfail\fR it links to the instruction labeled either "exit/ok" or "exit/fail", depending on the current condition code, and tagging it with the current condition code For the other two modes it links to the instruction labeled "exit/return", tagging it condition code \fBalways\fR, independent the current condition code\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::Who\fR \fIlabel\fR This command returns a reference to the instruction labeled with \fIlabel\fR\&. .TP \fB::grammar::me::cpu::gasm::/Label\fR \fIname\fR This command labels the \fIanchor\fR with \fIname\fR\&. \fINote\fR that an instruction can have more than one label\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::/Clear\fR This command clears the \fIanchor\fR, leaving it undefined, and further resets the current condition code to \fBalways\fR\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::/Ok\fR This command sets the current condition code to \fBok\fR\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::/Fail\fR This command sets the current condition code to \fBfail\fR\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::/At\fR \fIname\fR This command sets the \fIanchor\fR to the instruction labeled with \fIname\fR, and further resets the current condition code to \fBalways\fR\&. .sp The command returns the empty string as its result\&. .TP \fB::grammar::me::cpu::gasm::/CloseLoop\fR This command marks the \fIanchor\fR as the last instruction in a loop body, by creating the attribute \fBLOOP\fR\&. .sp The command returns the empty string as its result\&. .PP .SH "BUGS, IDEAS, FEEDBACK" This document, and the package it describes, will undoubtedly contain bugs and other problems\&. Please report such in the category \fIgrammar_me\fR of the \fITcllib Trackers\fR [http://core\&.tcl\&.tk/tcllib/reportlist]\&. Please also report any ideas for enhancements you may have for either package and/or documentation\&. .SH KEYWORDS assembler, grammar, graph, parsing, tree, virtual machine .SH CATEGORY Grammars and finite automata .SH COPYRIGHT .nf Copyright (c) 2005 Andreas Kupries .fi