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1 | # Assembler.pm |
2 | # |
3 | # Copyright (c) 1996 Malcolm Beattie |
4 | # |
5 | # You may distribute under the terms of either the GNU General Public |
6 | # License or the Artistic License, as specified in the README file. |
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7 | |
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8 | package B::Assembler; |
9 | use Exporter; |
10 | use B qw(ppname); |
11 | use B::Asmdata qw(%insn_data @insn_name); |
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12 | use Config qw(%Config); |
13 | require ByteLoader; # we just need its $VERSIOM |
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14 | |
15 | @ISA = qw(Exporter); |
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16 | @EXPORT_OK = qw(assemble_fh newasm endasm assemble); |
17 | $VERSION = 0.02; |
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18 | |
19 | use strict; |
20 | my %opnumber; |
21 | my ($i, $opname); |
22 | for ($i = 0; defined($opname = ppname($i)); $i++) { |
23 | $opnumber{$opname} = $i; |
24 | } |
25 | |
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26 | my($linenum, $errors, $out); # global state, set up by newasm |
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27 | |
28 | sub error { |
29 | my $str = shift; |
30 | warn "$linenum: $str\n"; |
31 | $errors++; |
32 | } |
33 | |
34 | my $debug = 0; |
35 | sub debug { $debug = shift } |
36 | |
37 | # |
38 | # First define all the data conversion subs to which Asmdata will refer |
39 | # |
40 | |
41 | sub B::Asmdata::PUT_U8 { |
42 | my $arg = shift; |
43 | my $c = uncstring($arg); |
44 | if (defined($c)) { |
45 | if (length($c) != 1) { |
46 | error "argument for U8 is too long: $c"; |
47 | $c = substr($c, 0, 1); |
48 | } |
49 | } else { |
50 | $c = chr($arg); |
51 | } |
52 | return $c; |
53 | } |
54 | |
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55 | sub B::Asmdata::PUT_U16 { pack("S", $_[0]) } |
56 | sub B::Asmdata::PUT_U32 { pack("L", $_[0]) } |
57 | sub B::Asmdata::PUT_I32 { pack("L", $_[0]) } |
58 | sub B::Asmdata::PUT_NV { sprintf("%s\0", $_[0]) } # "%lf" looses precision and pack('d',...) |
59 | # may not even be portable between compilers |
60 | sub B::Asmdata::PUT_objindex { pack("L", $_[0]) } # could allow names here |
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61 | sub B::Asmdata::PUT_svindex { &B::Asmdata::PUT_objindex } |
62 | sub B::Asmdata::PUT_opindex { &B::Asmdata::PUT_objindex } |
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63 | sub B::Asmdata::PUT_pvindex { &B::Asmdata::PUT_objindex } |
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64 | |
65 | sub B::Asmdata::PUT_strconst { |
66 | my $arg = shift; |
67 | $arg = uncstring($arg); |
68 | if (!defined($arg)) { |
69 | error "bad string constant: $arg"; |
70 | return ""; |
71 | } |
72 | if ($arg =~ s/\0//g) { |
73 | error "string constant argument contains NUL: $arg"; |
74 | } |
75 | return $arg . "\0"; |
76 | } |
77 | |
78 | sub B::Asmdata::PUT_pvcontents { |
79 | my $arg = shift; |
80 | error "extraneous argument: $arg" if defined $arg; |
81 | return ""; |
82 | } |
83 | sub B::Asmdata::PUT_PV { |
84 | my $arg = shift; |
85 | $arg = uncstring($arg); |
86 | error "bad string argument: $arg" unless defined($arg); |
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87 | return pack("L", length($arg)) . $arg; |
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88 | } |
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89 | sub B::Asmdata::PUT_comment_t { |
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90 | my $arg = shift; |
91 | $arg = uncstring($arg); |
92 | error "bad string argument: $arg" unless defined($arg); |
93 | if ($arg =~ s/\n//g) { |
94 | error "comment argument contains linefeed: $arg"; |
95 | } |
96 | return $arg . "\n"; |
97 | } |
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98 | sub B::Asmdata::PUT_double { sprintf("%s\0", $_[0]) } # see PUT_NV above |
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99 | sub B::Asmdata::PUT_none { |
100 | my $arg = shift; |
101 | error "extraneous argument: $arg" if defined $arg; |
102 | return ""; |
103 | } |
104 | sub B::Asmdata::PUT_op_tr_array { |
105 | my $arg = shift; |
106 | my @ary = split(/\s*,\s*/, $arg); |
107 | if (@ary != 256) { |
108 | error "wrong number of arguments to op_tr_array"; |
109 | @ary = (0) x 256; |
110 | } |
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111 | return pack("S256", @ary); |
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112 | } |
113 | # XXX Check this works |
114 | sub B::Asmdata::PUT_IV64 { |
115 | my $arg = shift; |
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116 | return pack("LL", $arg >> 32, $arg & 0xffffffff); |
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117 | } |
118 | |
119 | my %unesc = (n => "\n", r => "\r", t => "\t", a => "\a", |
120 | b => "\b", f => "\f", v => "\013"); |
121 | |
122 | sub uncstring { |
123 | my $s = shift; |
124 | $s =~ s/^"// and $s =~ s/"$// or return undef; |
125 | $s =~ s/\\(\d\d\d|.)/length($1) == 3 ? chr(oct($1)) : ($unesc{$1}||$1)/eg; |
126 | return $s; |
127 | } |
128 | |
129 | sub strip_comments { |
130 | my $stmt = shift; |
131 | # Comments only allowed in instructions which don't take string arguments |
132 | $stmt =~ s{ |
133 | (?sx) # Snazzy extended regexp coming up. Also, treat |
134 | # string as a single line so .* eats \n characters. |
135 | ^\s* # Ignore leading whitespace |
136 | ( |
137 | [^"]* # A double quote '"' indicates a string argument. If we |
138 | # find a double quote, the match fails and we strip nothing. |
139 | ) |
140 | \s*\# # Any amount of whitespace plus the comment marker... |
141 | .*$ # ...which carries on to end-of-string. |
142 | }{$1}; # Keep only the instruction and optional argument. |
143 | return $stmt; |
144 | } |
145 | |
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146 | # create the ByteCode header: magic, archname, ByteLoader $VERSION, ivsize, |
147 | # ptrsize, byteorder |
148 | # nvtype is irrelevant (floats are stored as strings) |
149 | # byteorder is strconst not U32 because of varying size issues |
150 | |
151 | sub gen_header { |
152 | my $header = ""; |
153 | |
154 | $header .= B::Asmdata::PUT_U32(0x43424c50); # 'PLBC' |
155 | $header .= B::Asmdata::PUT_strconst('"' . $Config{archname}. '"'); |
156 | $header .= B::Asmdata::PUT_strconst(qq["$ByteLoader::VERSION"]); |
157 | $header .= B::Asmdata::PUT_U32($Config{ivsize}); |
158 | $header .= B::Asmdata::PUT_U32($Config{ptrsize}); |
159 | $header .= B::Asmdata::PUT_strconst(sprintf(qq["0x%s"], $Config{byteorder})); |
160 | |
161 | $header; |
162 | } |
163 | |
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164 | sub parse_statement { |
165 | my $stmt = shift; |
166 | my ($insn, $arg) = $stmt =~ m{ |
167 | (?sx) |
168 | ^\s* # allow (but ignore) leading whitespace |
169 | (.*?) # Instruction continues up until... |
170 | (?: # ...an optional whitespace+argument group |
171 | \s+ # first whitespace. |
172 | (.*) # The argument is all the rest (newlines included). |
173 | )?$ # anchor at end-of-line |
174 | }; |
175 | if (defined($arg)) { |
176 | if ($arg =~ s/^0x(?=[0-9a-fA-F]+$)//) { |
177 | $arg = hex($arg); |
178 | } elsif ($arg =~ s/^0(?=[0-7]+$)//) { |
179 | $arg = oct($arg); |
180 | } elsif ($arg =~ /^pp_/) { |
181 | $arg =~ s/\s*$//; # strip trailing whitespace |
182 | my $opnum = $opnumber{$arg}; |
183 | if (defined($opnum)) { |
184 | $arg = $opnum; |
185 | } else { |
186 | error qq(No such op type "$arg"); |
187 | $arg = 0; |
188 | } |
189 | } |
190 | } |
191 | return ($insn, $arg); |
192 | } |
193 | |
194 | sub assemble_insn { |
195 | my ($insn, $arg) = @_; |
196 | my $data = $insn_data{$insn}; |
197 | if (defined($data)) { |
198 | my ($bytecode, $putsub) = @{$data}[0, 1]; |
199 | my $argcode = &$putsub($arg); |
200 | return chr($bytecode).$argcode; |
201 | } else { |
202 | error qq(no such instruction "$insn"); |
203 | return ""; |
204 | } |
205 | } |
206 | |
207 | sub assemble_fh { |
208 | my ($fh, $out) = @_; |
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209 | my $line; |
210 | my $asm = newasm($out); |
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211 | while ($line = <$fh>) { |
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212 | assemble($line); |
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213 | } |
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214 | endasm(); |
215 | } |
216 | |
217 | sub newasm { |
218 | my($outsub) = @_; |
219 | |
220 | die "Invalid printing routine for B::Assembler\n" unless ref $outsub eq 'CODE'; |
221 | die <<EOD if ref $out; |
222 | Can't have multiple byteassembly sessions at once! |
223 | (perhaps you forgot an endasm()?) |
224 | EOD |
225 | |
226 | $linenum = $errors = 0; |
227 | $out = $outsub; |
228 | |
229 | $out->(gen_header()); |
230 | } |
231 | |
232 | sub endasm { |
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233 | if ($errors) { |
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234 | die "There were $errors assembly errors\n"; |
235 | } |
236 | $linenum = $errors = $out = 0; |
237 | } |
238 | |
239 | sub assemble { |
240 | my($line) = @_; |
241 | my ($insn, $arg); |
242 | $linenum++; |
243 | chomp $line; |
244 | if ($debug) { |
245 | my $quotedline = $line; |
246 | $quotedline =~ s/\\/\\\\/g; |
247 | $quotedline =~ s/"/\\"/g; |
248 | $out->(assemble_insn("comment", qq("$quotedline"))); |
249 | } |
250 | $line = strip_comments($line) or next; |
251 | ($insn, $arg) = parse_statement($line); |
252 | $out->(assemble_insn($insn, $arg)); |
253 | if ($debug) { |
254 | $out->(assemble_insn("nop", undef)); |
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255 | } |
256 | } |
257 | |
258 | 1; |
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259 | |
260 | __END__ |
261 | |
262 | =head1 NAME |
263 | |
264 | B::Assembler - Assemble Perl bytecode |
265 | |
266 | =head1 SYNOPSIS |
267 | |
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268 | use B::Assembler qw(newasm endasm assemble); |
269 | newasm(\&printsub); # sets up for assembly |
270 | assemble($buf); # assembles one line |
271 | endasm(); # closes down |
272 | |
273 | use B::Assembler qw(assemble_fh); |
274 | assemble_fh($fh, \&printsub); # assemble everything in $fh |
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275 | |
276 | =head1 DESCRIPTION |
277 | |
278 | See F<ext/B/B/Assembler.pm>. |
279 | |
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280 | =head1 AUTHORS |
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281 | |
282 | Malcolm Beattie, C<mbeattie@sable.ox.ac.uk> |
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283 | Per-statement interface by Benjamin Stuhl, C<sho_pi@hotmail.com> |
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284 | |
285 | =cut |