From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:39225) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gpJZy-0000j3-NQ for qemu-devel@nongnu.org; Thu, 31 Jan 2019 16:08:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gpJZx-0008C1-Mj for qemu-devel@nongnu.org; Thu, 31 Jan 2019 16:08:58 -0500 Received: from mail-pg1-x531.google.com ([2607:f8b0:4864:20::531]:47002) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gpJZx-00088K-6m for qemu-devel@nongnu.org; Thu, 31 Jan 2019 16:08:57 -0500 Received: by mail-pg1-x531.google.com with SMTP id w7so1869994pgp.13 for ; Thu, 31 Jan 2019 13:08:56 -0800 (PST) From: Richard Henderson Date: Thu, 31 Jan 2019 13:08:50 -0800 Message-Id: <20190131210851.9842-2-richard.henderson@linaro.org> In-Reply-To: <20190131210851.9842-1-richard.henderson@linaro.org> References: <20190131210851.9842-1-richard.henderson@linaro.org> Subject: [Qemu-devel] [PATCH 1/2] decodetree: Initial support for variable-length ISAs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: ysato@users.sourceforge.jp Assuming that the ISA clearly describes how to determine the length of the instruction, and the ISA has a reasonable maximum instruction length, the input to the decoder can be right-justified in an appropriate insn word. This is not 100% convenient, as out-of-line %fields are numbered relative to the maximum instruction length, but this appears to still be usable. Signed-off-by: Richard Henderson --- scripts/decodetree.py | 38 ++++++++++++++++++++++++++++---------- 1 file changed, 28 insertions(+), 10 deletions(-) diff --git a/scripts/decodetree.py b/scripts/decodetree.py index 2f8b5a1c92..5fb0acaa15 100755 --- a/scripts/decodetree.py +++ b/scripts/decodetree.py @@ -159,6 +159,7 @@ import getopt insnwidth = 32 insnmask = 0xffffffff +variablewidth = False fields = {} arguments = {} formats = {} @@ -420,7 +421,7 @@ class Arguments: class General: """Common code between instruction formats and instruction patterns""" - def __init__(self, name, lineno, base, fixb, fixm, udfm, fldm, flds): + def __init__(self, name, lineno, base, fixb, fixm, udfm, fldm, flds, w): self.name = name self.file = input_file self.lineno = lineno @@ -430,6 +431,7 @@ class General: self.undefmask = udfm self.fieldmask = fldm self.fields = flds + self.width = w def __str__(self): r = self.name @@ -597,7 +599,7 @@ def infer_argument_set(flds): return arg -def infer_format(arg, fieldmask, flds): +def infer_format(arg, fieldmask, flds, width): global arguments global formats global decode_function @@ -616,6 +618,8 @@ def infer_format(arg, fieldmask, flds): continue if fieldmask != fmt.fieldmask: continue + if width != fmt.width: + continue if not eq_fields_for_fmts(flds, fmt.fields): continue return (fmt, const_flds) @@ -624,7 +628,7 @@ def infer_format(arg, fieldmask, flds): if not arg: arg = infer_argument_set(flds) - fmt = Format(name, 0, arg, 0, 0, 0, fieldmask, var_flds) + fmt = Format(name, 0, arg, 0, 0, 0, fieldmask, var_flds, width) formats[name] = fmt return (fmt, const_flds) @@ -640,6 +644,7 @@ def parse_generic(lineno, is_format, name, toks): global re_ident global insnwidth global insnmask + global variablewidth fixedmask = 0 fixedbits = 0 @@ -725,8 +730,15 @@ def parse_generic(lineno, is_format, name, toks): error(lineno, 'invalid token "{0}"'.format(t)) width += shift + if variablewidth and width < insnwidth and width % 8 == 0: + shift = insnwidth - width + fixedbits <<= shift + fixedmask <<= shift + undefmask <<= shift + undefmask |= (1 << shift) - 1 + # We should have filled in all of the bits of the instruction. - if not (is_format and width == 0) and width != insnwidth: + elif not (is_format and width == 0) and width != insnwidth: error(lineno, 'definition has {0} bits'.format(width)) # Do not check for fields overlaping fields; one valid usage @@ -752,7 +764,7 @@ def parse_generic(lineno, is_format, name, toks): if name in formats: error(lineno, 'duplicate format name', name) fmt = Format(name, lineno, arg, fixedbits, fixedmask, - undefmask, fieldmask, flds) + undefmask, fieldmask, flds, width) formats[name] = fmt else: # Patterns can reference a format ... @@ -762,12 +774,14 @@ def parse_generic(lineno, is_format, name, toks): error(lineno, 'pattern specifies both format and argument set') if fixedmask & fmt.fixedmask: error(lineno, 'pattern fixed bits overlap format fixed bits') + if width != fmt.width: + error(lineno, 'pattern uses format of different width') fieldmask |= fmt.fieldmask fixedbits |= fmt.fixedbits fixedmask |= fmt.fixedmask undefmask |= fmt.undefmask else: - (fmt, flds) = infer_format(arg, fieldmask, flds) + (fmt, flds) = infer_format(arg, fieldmask, flds, width) arg = fmt.base for f in flds.keys(): if f not in arg.fields: @@ -779,7 +793,7 @@ def parse_generic(lineno, is_format, name, toks): if f not in flds.keys() and f not in fmt.fields.keys(): error(lineno, 'field {0} not initialized'.format(f)) pat = Pattern(name, lineno, fmt, fixedbits, fixedmask, - undefmask, fieldmask, flds) + undefmask, fieldmask, flds, width) patterns.append(pat) # Validate the masks that we have assembled. @@ -987,12 +1001,14 @@ def main(): global insntype global insnmask global decode_function + global variablewidth decode_scope = 'static ' - long_opts = ['decode=', 'translate=', 'output=', 'insnwidth='] + long_opts = ['decode=', 'translate=', + 'output=', 'insnwidth=', 'varinsnwidth='] try: - (opts, args) = getopt.getopt(sys.argv[1:], 'o:w:', long_opts) + (opts, args) = getopt.getopt(sys.argv[1:], 'o:vw:', long_opts) except getopt.GetoptError as err: error(0, err) for o, a in opts: @@ -1004,7 +1020,9 @@ def main(): elif o == '--translate': translate_prefix = a translate_scope = '' - elif o in ('-w', '--insnwidth'): + elif o in ('-w', '--insnwidth', '--varinsnwidth'): + if o == '--varinsnwidth': + variablewidth = True insnwidth = int(a) if insnwidth == 16: insntype = 'uint16_t' -- 2.17.2