Hi Richard,
+# Field examples:
+#
+# %disp 0:s16 -- sextract(i, 0, 16)
+# %imm9 16:6 10:3 -- extract(i, 16, 6) << 3 | extract(i, 10, 3)
startindex:endindex for unnamed_field is more intuitive. As any ISA
manual would specify those.
+#
+# It is recommended, but not required, that all field_ref and args_ref
+# appear at the end of the line, not interleaving with fixedbit_elf or
+# field_elt.
This seems not very intuitive to me. Why specify the field_refs at the
end and fill the space they occupy with '.'? I'd prefer interleaving the
reference to make it more readable (which doesn't work so far)
+# Pattern examples:
+#
+# addl_r 010000 ..... ..... .... 0000000 ..... @opr
+# addl_i 010000 ..... ..... .... 0000000 ..... @opi
We should note in the documentation where the LSB is. Got that the wrong
way in the first time I implemented RISC-V .
+def str_indent(c):
+ """Return a string with C spaces"""
+ r = ''
+ for i in range(0, c):
+ r += ' '
+ return r
return ' ' * c
+def popcount(b):
+ b = (b & 0x55555555) + ((b >> 1) & 0x55555555)
+ b = (b & 0x33333333) + ((b >> 2) & 0x33333333)
+ b = (b & 0x0f0f0f0f) + ((b >> 4) & 0x0f0f0f0f)
+ b = (b + (b >> 8)) & 0x00ff00ff
+ b = (b + (b >> 16)) & 0xffff
+ return b
We really don't need to look for efficiency here?
return bin(b).count('1')
+def parse_arguments(lineno, name, toks):
+ """Parse one argument set from TOKS at LINENO"""
+ global arguments
+ global re_ident
+
+ flds = []
arg_fields is a better name. Likewise for other places containing flds.
Such that one knows where this fields belongs to.
+ elif name[0] == '&':
+ parse_arguments(lineno, name[1:], toks)
+ elif name[0] == '@':
+ parse_generic(lineno, True, name[1:], toks)
+ else:
+ parse_generic(lineno, False, name, toks)
+ toks = []
Why do we have a generic function for pat and fields? Rather make it two
parse functions and split subparsings that they share into generic
functions, instead of doing the distinction in parse_generic().
+ for p in pats:
+ pnames.append(p.name)
+ #pdb.set_trace()
Guess you forgot that ;)
+ long_opts = [ 'decode=', 'translate=', 'header=', 'output=' ]
+ try:
+ (opts, args) = getopt.getopt(sys.argv[1:], 'h:o:', long_opts)
+ except getopt.GetoptError as err:
+ error(0, err)
+ for o, a in opts:
+ if o in ('-h', '--header'):
+ h_file = a
+ elif o in ('-o', '--output'):
+ c_file = a
+ elif o == '--decode':
+ decode_function = a
+ elif o == '--translate':
+ translate_prefix = a
+ else:
+ assert False, 'unhandled option'
Please use argsparse
On a more general note. Do you really need to invent your own
description format + parser? Why not reuse an existing markup language?
Can you give me a rationale?
That said, your description language looks very readable, even though
I'm not a big fan of symbol prefixes ;).
Thanks for improving my original approach.
Cheers,
Bastian
