18a68c82401abb1270d051687f2a53ae25dca214
1 package App
::Scheme79asm
;
7 use Data
::Dumper qw
/Dumper/;
8 use Data
::SExpression qw
/consp scalarp/;
9 use Scalar
::Util qw
/looks_like_number/;
11 our $VERSION = '0.003';
39 *consp
= *Data
::SExpression
::consp
;
40 *scalarp
= *Data
::SExpression
::scalarp
;
43 my ($self, $sexp, $location) = @_;
44 die 'Toplevel is not a list: ', Dumper
($sexp), "\n" unless ref $sexp eq 'ARRAY';
45 my ($type, @addrs) = @
$sexp;
48 die 'Type of toplevel is not atom: '. Dumper
($type), "\n" unless scalarp
($type);
51 $addr = $self->{freeptr
} + 1;
52 $self->{freeptr
} += @addrs;
53 $self->process($addrs[$_], $addr + $_) for 0 .. $#addrs;
58 $addr = $self->process($addr) if ref $addr eq 'ARRAY';
59 die 'Addr of toplevel is not atom: ', Dumper
($addr), "\n" unless scalarp
($addr);
61 my ($comment_type, $comment_addr) = ($type, $addr);
63 unless (looks_like_number
$addr) { # is symbol
64 unless (exists $self->{symbols
}{$addr}) {
65 $self->{symbols
}{$addr} = $self->{nsymbols
};
68 $addr = $self->{symbols
}{$addr}
71 die 'Computed addr is not a number: ', Dumper
($addr), "\n" unless looks_like_number
$addr;
73 if (ref $type eq 'Data::SExpression::Symbol') {
74 die "No such type: $type\n" unless exists $TYPES{$type};
75 $type = $TYPES{$type};
76 } elsif (!looks_like_number
$type) {
77 die "Type is not a number or symbol: $type\n"
80 $addr += (1 << $self->{addr_bits
}) if $addr < 0;
81 die "Type too large: $type\n" unless $type < (1 << $self->{type_bits
});
82 die "Addr too large: $addr\n" unless $addr < (1 << $self->{addr_bits
});
83 my $result = ($type << $self->{addr_bits
}) + $addr;
86 $location = $self->{freeptr
}
88 $self->{memory
}[$location] = $result;
89 $self->{comment
}[$location] = "$comment_type $comment_addr";
94 my ($self, $string) = @_;
95 my $ds = Data
::SExpression
->new({symbol_case
=> 'up', use_symbol_class
=> 1, fold_lists
=> 1});
99 last if $string =~ /^\s*$/;
100 ($sexp, $string) = $ds->read($string);
101 $self->process($sexp)
107 $self->{memory
}[5] = $self->{memory
}[$self->{freeptr
}];
108 $self->{comment
}[5] = $self->{comment
}[$self->{freeptr
}];
109 $self->{memory
}[4] = $self->{freeptr
};
110 delete $self->{memory
}[$self->{freeptr
}]
114 my ($class, %args) = @_;
115 $args{type_bits
} //= 3;
116 $args{addr_bits
} //= 8;
117 $args{freeptr
} //= 6;
118 $args{memory
} //= [0, 0, (1<<$args{addr_bits
}), (1<<$args{addr_bits
}), 0, 0, 0];
119 $args{symbols
}{T
} = 2;
121 $args{comment
} = ['(cdr part of NIL)', '(car part of NIL)', '(cdr part of T)', '(car part of T)', '(free storage pointer)', '', '(result of computation)'];
126 my ($self, $fh) = @_;
129 die "addr_bits + type_bits >= 16\n"if $self->{addr_bits
} + $self->{type_bits
} > 16;
131 my $length = @
{$self->{memory
}};
132 print $fh pack('n', $length);
133 for (@
{$self->{memory
}}) {
134 print $fh pack('n', $_)
139 my ($self, $fh) = @_;
142 my $bits = $self->{type_bits
} + $self->{addr_bits
};
143 my $index_length = length $#{$self->{memory}};
144 my $index_format = '%' . $index_length . 'd';
145 for my $index (0 .. $#{$self->{memory}}) {
146 my $val = $self->{memory
}[$index];
147 my $comment = $self->{comment
}[$index];
149 $val = "${bits}'d$val"
151 $val = $val ?
sprintf "%d'b%0${bits}b", $bits, $val : '0';
153 my $spaces = ' ' x
($bits + 5 - (length $val));
154 $index = sprintf $index_format, $index;
155 say $fh "mem[$index] <= $val;$spaces // $comment"
159 sub parse_and_print_binary16
{
160 my ($self, $string, $fh) = @_;
161 $self->parse($string);
163 $self->print_binary16($fh);
166 sub parse_and_print_verilog
{
167 my ($self, $string, $fh) = @_;
168 $self->parse($string);
170 $self->print_verilog($fh);
180 App::Scheme79asm - assemble sexp to Verilog ROM for SIMPLE processor
184 use App::Scheme79asm;
185 my $asm = App::Scheme79asm->new(type_bits => 3, addr_bits => 5);
186 $asm->parse_and_print_verilog('(number 70)');
190 SIMPLE is a LISP processor defined in the 1979
191 B<Design of LISP-Based Processors> paper by Steele and Sussman.
193 The SIMPLE processor expects input in a particular tagged-pointer
194 format. This module takes a string containing a sequence of
195 S-expressions. Each S-expression is a list of one of three types:
197 C<(tag value)>, for example C<(symbol nil)>, represents a value to be
198 put in memory (for example a number, or a symbol, or a variable
201 C<(tag list)>, where C<list> is of one of these three types,
202 represents a tagged pointer. In this case, C<list> is (recursively)
203 laid out in memory as per these rules, and a pointer to that location
204 (and tagged C<tag>) is put somewhere in memory.
206 C<(tag list1 list2)>, where C<list1> and C<list2> are of one of these
207 three types (not necessarily the same type). In this case, C<list1>
208 and C<list2> are (recursively) laid out in memory such that C<list1>
209 is at position X and C<list2> is at position X+1, and a pointer of
210 type tag and value X is put somewhere in memory.
212 After this process the very last pointer placed in memory is moved to
213 the special location 5 (which is where SIMPLE expects to find the
214 expression to be evaluated).
216 In normal use a single S-expression will be supplied, representing an
219 The C<tag> is either a number, a type, or a primitive.
220 The available types are:
226 =item SYMBOL (syn. NUMBER)
228 =item VAR (syn. VARIABLE)
232 =item PROC (syn. PROCEDURE)
234 =item IF (syn. COND, CONDITIONAL)
238 =item QUOTE (syn. QUOTED)
242 The available primitives are:
264 The following methods are available:
268 =item App::Scheme79asm->B<new>([key => value, key => value, ...])
270 Create a new assembler object. Takes a list of keys and values, here
271 are the possible keys:
279 A word is made of a type and an address, with the type occupying the
280 most significant C<type_bits> (default 3) bits, and the address
281 occupying the least significant C<address_bits> (default 8) bits.
282 Therefore the word size is C<type_bits + address_bits> (default 13).
286 A pointer to the last used byte in memory (default 6). The program
287 will be laid out starting with location C<freeptr + 1>.
291 The initial contents of the memory. Note that locations 4, 5, 6 will
292 be overwritten, as will every location larger than the value of
297 The initial comments for memory entries. C<< $comment->[$i] >> is the
298 comment for C<< $memory->[$i] >>.
302 The initial symbol map, as a hashref from symbol name to the index of
303 that symbol. Defaults to C<< {T => 2} >>.
307 The number to give to the "next" symbol (default 3, because T is
312 =item $asm->B<parse>(I<$string>)
314 Parse a sequence of S-expressions and lay it out in memory.
315 Can be called multiple times to lay out multiple sequences of
316 S-expressions one after another.
318 =item $asm->B<process>(I<$sexp>)
320 Given an already-parsed sexp (meaning a
321 L<Data::SExpression> object), lay it out in memory.
322 Can be called multiple times to lay out multiple sequences of
323 S-expressions one after another.
325 =item $asm->B<finish>
327 Move the last pointer to position 5, and put the free pointer at
328 position 4. After all sequences of S-expressions have been given to
329 B<parse>, this method should be called.
331 =item $asm->B<print_binary16>([I<$fh>])
333 Print the length of the memory (as a big-endian 16-bit value),
334 followed by the memory contents as a sequence of big-endian 16-bit
335 values to the given filehandle (default STDOUT). Dies if
336 C<addr_bits + type_bits> is more than 16.
338 Big-endian 16-bit values can be decoded with C<unpack 'n', $value>.
340 =item $asm->B<print_verilog>([I<$fh>])
342 Print a block of Verilog code assigning the memory contents to an
343 array named C<mem> to the given filehandle (default STDOUT).
345 =item $asm->B<parse_and_print_binary16>(I<$string>[, I<$fh>])
347 Convenience method that calls B<parse>($string), B<finish>, and then
348 B<print_binary16>($fh).
350 =item $asm->B<parse_and_print_verilog>(I<$string>[, I<$fh>])
352 Convenience method that calls B<parse>($string), B<finish>, and then
353 B<print_verilog>($fh).
359 L<http://repository.readscheme.org/ftp/papers/ai-lab-pubs/AIM-514.pdf>
363 Marius Gavrilescu, E<lt>marius@ieval.roE<gt>
365 =head1 COPYRIGHT AND LICENSE
367 Copyright (C) 2018 by Marius Gavrilescu
369 This library is free software; you can redistribute it and/or modify
370 it under the same terms as Perl itself, either Perl version 5.24.3 or,
371 at your option, any later version of Perl 5 you may have available.
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