-# see qemu/target/ppc/mmu-radix64.c for reference
-class RADIX:
- def __init__(self, mem, caller):
- self.mem = mem
- self.caller = caller
-
- def ld(self, address, width=8, swap=True, check_in_mem=False):
- print("RADIX: ld from addr 0x{:x} width {:d}".format(address, width))
-
- pte = self._walk_tree()
- # use pte to caclculate phys address
- #mem.ld(address,width,swap,check_in_mem)
-
- # TODO implement
- # def st(self, addr, v, width=8, swap=True):
- # def memassign(self, addr, sz, val):
- def _next_level(self):
- return True
- ## DSISR_R_BADCONFIG
- ## read_entry
- ## DSISR_NOPTE
- ## Prepare for next iteration
-
- def _walk_tree(self):
- # walk tree starts on prtbl
- while True:
- ret = self._next_level()
- if ret: return ret
-
- def _segment_check(self):
- """checks segment valid
- mbits := '0' & r.mask_size;
- v.shift := r.shift + (31 - 12) - mbits;
- nonzero := or(r.addr(61 downto 31) and not finalmask(30 downto 0));
- if r.addr(63) /= r.addr(62) or nonzero = '1' then
- v.state := RADIX_FINISH;
- v.segerror := '1';
- elsif mbits < 5 or mbits > 16 or mbits > (r.shift + (31 - 12)) then
- v.state := RADIX_FINISH;
- v.badtree := '1';
- else
- v.state := RADIX_LOOKUP;
- """
-
- def _check_perms(self):
- """check page permissions
- -- test leaf bit
- if data(62) = '1' then
- -- check permissions and RC bits
- perm_ok := '0';
- if r.priv = '1' or data(3) = '0' then
- if r.iside = '0' then
- perm_ok := data(1) or (data(2) and not r.store);
- else
- -- no IAMR, so no KUEP support for now
- -- deny execute permission if cache inhibited
- perm_ok := data(0) and not data(5);
- end if;
- end if;
- rc_ok := data(8) and (data(7) or not r.store);
- if perm_ok = '1' and rc_ok = '1' then
- v.state := RADIX_LOAD_TLB;
- else
- v.state := RADIX_FINISH;
- v.perm_err := not perm_ok;
- -- permission error takes precedence over RC error
- v.rc_error := perm_ok;
- end if;
- """
-
-
-class Mem:
-
- def __init__(self, row_bytes=8, initial_mem=None):
- self.mem = {}
- self.bytes_per_word = row_bytes
- self.word_log2 = math.ceil(math.log2(row_bytes))
- print("Sim-Mem", initial_mem, self.bytes_per_word, self.word_log2)
- if not initial_mem:
- return
-
- # different types of memory data structures recognised (for convenience)
- if isinstance(initial_mem, list):
- initial_mem = (0, initial_mem)
- if isinstance(initial_mem, tuple):
- startaddr, mem = initial_mem
- initial_mem = {}
- for i, val in enumerate(mem):
- initial_mem[startaddr + row_bytes*i] = (val, row_bytes)
-
- for addr, (val, width) in initial_mem.items():
- #val = swap_order(val, width)
- self.st(addr, val, width, swap=False)
-
- def _get_shifter_mask(self, wid, remainder):
- shifter = ((self.bytes_per_word - wid) - remainder) * \
- 8 # bits per byte
- # XXX https://bugs.libre-soc.org/show_bug.cgi?id=377
- # BE/LE mode?
- shifter = remainder * 8
- mask = (1 << (wid * 8)) - 1
- print("width,rem,shift,mask", wid, remainder, hex(shifter), hex(mask))
- return shifter, mask
-
- # TODO: Implement ld/st of lesser width
- def ld(self, address, width=8, swap=True, check_in_mem=False):
- print("ld from addr 0x{:x} width {:d}".format(address, width))
- remainder = address & (self.bytes_per_word - 1)
- address = address >> self.word_log2
- assert remainder & (width - 1) == 0, "Unaligned access unsupported!"
- if address in self.mem:
- val = self.mem[address]
- elif check_in_mem:
- return None
- else:
- val = 0
- print("mem @ 0x{:x} rem {:d} : 0x{:x}".format(address, remainder, val))
-
- if width != self.bytes_per_word:
- shifter, mask = self._get_shifter_mask(width, remainder)
- print("masking", hex(val), hex(mask << shifter), shifter)
- val = val & (mask << shifter)
- val >>= shifter
- if swap:
- val = swap_order(val, width)
- print("Read 0x{:x} from addr 0x{:x}".format(val, address))
- return val
-
- def st(self, addr, v, width=8, swap=True):
- staddr = addr
- remainder = addr & (self.bytes_per_word - 1)
- addr = addr >> self.word_log2
- print("Writing 0x{:x} to ST 0x{:x} "
- "memaddr 0x{:x}/{:x}".format(v, staddr, addr, remainder, swap))
- assert remainder & (width - 1) == 0, "Unaligned access unsupported!"
- if swap:
- v = swap_order(v, width)
- if width != self.bytes_per_word:
- if addr in self.mem:
- val = self.mem[addr]
- else:
- val = 0
- shifter, mask = self._get_shifter_mask(width, remainder)
- val &= ~(mask << shifter)
- val |= v << shifter
- self.mem[addr] = val
- else:
- self.mem[addr] = v
- print("mem @ 0x{:x}: 0x{:x}".format(addr, self.mem[addr]))
-
- def __call__(self, addr, sz):
- val = self.ld(addr.value, sz, swap=False)
- print("memread", addr, sz, val)
- return SelectableInt(val, sz*8)
-
- def memassign(self, addr, sz, val):
- print("memassign", addr, sz, val)
- self.st(addr.value, val.value, sz, swap=False)
-
-