folkert/python-pdp1170
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Pretty important bug fix for byte instruction register semantics

Browse source
This commit is contained in:
Neil Webber 2023-10-28 13:33:20 -05:00
parent e3c0782c72
commit e42601ae14
1 changed files with 8 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
machine.py
View file

@ -433,9 +433,10 @@ class PDP11:
case Rn, None, 1:
value = self.r[Rn] & 0o377
case Rn, bv, 1:
self.r[Rn] = bv
if bv > 127:
self.r[Rn] |= 0xFF00
# NOTE: The MOVB instruction has different semantics
# than this; it is coded explicitly in op11_movb()
self.r[Rn] &= 0o177400
self.r[Rn] |= (bv & 0o377)
return (value, b6) if rmw else value
# harder cases
@ -530,22 +531,16 @@ class PDP11:
# convenience, creates a breakpoint to stop at the given pc,
# optionally limited to a specific mode (KERNEL, USER, SUPERVISOR)
def run_until(self, *args, stoppc, stopmode=None, **kwargs):
"""Run processor with breakpoint at 'stopat'.
"""Run processor with breakpoint at 'stoppc'.
If stopat is an integer, stop at that PC value in any mode.
If stopat is a tuple, stop at (pc, mode) where mode
is self.KERNEL, self.SUPERVISOR or self.USER
if stopmode is None (default), stop at the stoppc in any mode.
Otherwise, only stop if mode is stopmode.
"""
bpt = PCBreakpoint(stoppc=stoppc, stopmode=stopmode)
return self.run(*args, breakpoint=bpt, **kwargs)
def run(self, *, pc=None, breakpoint=None):
"""Run the machine for a number of steps (instructions).
If steps is None (default), the machine runs until a HALT instruction
is encountered. It may run forever and the method might never return.
Otherwise, it runs for that many instructions (or until a HALT).
"""The CPU main loop - run the machine!
If pc is None (default) execution begins at the current pc; otherwise
the pc is set to the given value first.