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#
# Copyright OpenEmbedded Contributors
#
# SPDX-License-Identifier: GPL-2.0-only
#
# riscv_isa_to_tune(isa)
#
# Automatically translate a RISC-V ISA string to TUNE_FEATURES
#
# Abbreviations, such as rv32g -> rv32imaffd_zicsr_zifencei are supported.
#
# Profiles, such as rva22u64, are NOT supported, you must use ISA strings.
#
def riscv_isa_to_tune(isa):
_isa = isa.lower()
feature = []
iter = 0
# rv or riscv
if _isa[iter:].startswith('rv'):
feature.append('rv')
iter = iter + 2
elif _isa[iter:].startswith('riscv'):
feature.append('rv')
iter = iter + 5
else:
# Not a risc-v ISA!
return _isa
while (_isa[iter:]):
# Skip _ and whitespace
if _isa[iter] == '_' or _isa[iter].isspace():
iter = iter + 1
continue
# Length, just capture numbers here
if _isa[iter].isdigit():
iter_end = iter
while iter_end < len(_isa) and _isa[iter_end].isdigit():
iter_end = iter_end + 1
feature.append(_isa[iter:iter_end])
iter = iter_end
continue
# Typically i, e or g is next, followed by extensions.
# Extensions are single character, except for Z, Ss, Sh, Sm, Sv, and X
# If the extension starts with 'Z', 'S' or 'X' use the name until the next _, whitespace or end
if _isa[iter] in ['z', 's', 'x']:
ext_type = _isa[iter]
iter_end = iter + 1
# Multicharacter extension, these are supposed to have a _ before the next multicharacter extension
# See 37.4 and 37.5:
# 37.4: Underscores "_" may be used to separate ISA extensions...
# 37.5: All multi-letter extensions ... must be separated from other multi-letter extensions by an underscore...
# Some extensions permit only alphabetic characters, while others allow alphanumeric chartacters
while iter_end < len(_isa) and _isa[iter_end] != "_" and not _isa[iter_end].isspace():
iter_end = iter_end + 1
feature.append(_isa[iter:iter_end])
iter = iter_end
continue
# 'g' is special, it's an abbreviation for imafd_zicsr_zifencei
# When expanding the abbreviation, any additional letters must appear before the _z* extensions
if _isa[iter] == 'g':
_isa = 'imafd' + _isa[iter+1:] + '_zicsr_zifencei'
iter = 0
continue
feature.append(_isa[iter])
iter = iter + 1
continue
# Eliminate duplicates, but preserve the order
feature = list(dict.fromkeys(feature))
return ' '.join(feature)
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