changeset 2b4fe083d17b in /z/repo/gem5
details: http://repo.gem5.org/gem5?cmd=changeset;node=2b4fe083d17b
description:
slicc: support for transitions with a wildcard next state
This patches adds support for transitions of the form:
transition(START, EVENTS, *) { ACTIONS }
This allows a machine to collapse states that differ only in the next
state
transition to collapse into one, and can help shorten/simplfy some
protocols
significantly.
When * is encountered as an end state of a transition, the next state is
determined by calling the machine-specific getNextState function. The
next
state is determined before any actions of the transition execute, and
therefore the next state calculation cannot depend on any of the
transition
actions.
diffstat:
src/mem/slicc/parser.py | 9 +++++++--
src/mem/slicc/symbols/State.py | 8 ++++++++
src/mem/slicc/symbols/StateMachine.py | 13 +++++++++++--
src/mem/slicc/symbols/Transition.py | 15 ++++++++++++++-
4 files changed, 40 insertions(+), 5 deletions(-)
diffs (105 lines):
diff -r 51f40b101a56 -r 2b4fe083d17b src/mem/slicc/parser.py
--- a/src/mem/slicc/parser.py Mon Jul 20 09:15:18 2015 -0500
+++ b/src/mem/slicc/parser.py Mon Jul 20 09:15:18 2015 -0500
@@ -278,7 +278,7 @@
p[0] = ast.OutPortDeclAST(self, p[3], p[5], p[7], p[8])
def p_decl__trans0(self, p):
- "decl : TRANS '(' idents ',' idents ',' ident ')' idents"
+ "decl : TRANS '(' idents ',' idents ',' ident_or_star ')' idents"
p[0] = ast.TransitionDeclAST(self, [], p[3], p[5], p[7], p[9])
def p_decl__trans1(self, p):
@@ -286,7 +286,7 @@
p[0] = ast.TransitionDeclAST(self, [], p[3], p[5], None, p[7])
def p_decl__trans2(self, p):
- "decl : TRANS '(' idents ',' idents ',' ident ')' idents idents"
+ "decl : TRANS '(' idents ',' idents ',' ident_or_star ')' idents
idents"
p[0] = ast.TransitionDeclAST(self, p[9], p[3], p[5], p[7], p[10])
def p_decl__trans3(self, p):
@@ -506,6 +506,11 @@
"ident : IDENT"
p[0] = p[1]
+ def p_ident_or_star(self, p):
+ """ident_or_star : ident
+ | STAR"""
+ p[0] = p[1]
+
# Pair and pair lists
def p_pairs__list(self, p):
"pairs : ',' pairsx"
diff -r 51f40b101a56 -r 2b4fe083d17b src/mem/slicc/symbols/State.py
--- a/src/mem/slicc/symbols/State.py Mon Jul 20 09:15:18 2015 -0500
+++ b/src/mem/slicc/symbols/State.py Mon Jul 20 09:15:18 2015 -0500
@@ -30,5 +30,13 @@
class State(Symbol):
def __repr__(self):
return "[State: %s]" % self.ident
+ def isWildcard(self):
+ return False
+
+class WildcardState(State):
+ def __repr__(self):
+ return "[State: *]"
+ def isWildcard(self):
+ return True
__all__ = [ "State" ]
diff -r 51f40b101a56 -r 2b4fe083d17b src/mem/slicc/symbols/StateMachine.py
--- a/src/mem/slicc/symbols/StateMachine.py Mon Jul 20 09:15:18 2015 -0500
+++ b/src/mem/slicc/symbols/StateMachine.py Mon Jul 20 09:15:18 2015 -0500
@@ -1310,8 +1310,17 @@
case = self.symtab.codeFormatter()
# Only set next_state if it changes
if trans.state != trans.nextState:
- ns_ident = trans.nextState.ident
- case('next_state = ${ident}_State_${ns_ident};')
+ if trans.nextState.isWildcard():
+ # When * is encountered as an end state of a transition,
+ # the next state is determined by calling the
+ # machine-specific getNextState function. The next state
+ # is determined before any actions of the transition
+ # execute, and therefore the next state calculation cannot
+ # depend on any of the transitionactions.
+ case('next_state = getNextState(addr);')
+ else:
+ ns_ident = trans.nextState.ident
+ case('next_state = ${ident}_State_${ns_ident};')
actions = trans.actions
request_types = trans.request_types
diff -r 51f40b101a56 -r 2b4fe083d17b src/mem/slicc/symbols/Transition.py
--- a/src/mem/slicc/symbols/Transition.py Mon Jul 20 09:15:18 2015 -0500
+++ b/src/mem/slicc/symbols/Transition.py Mon Jul 20 09:15:18 2015 -0500
@@ -26,6 +26,7 @@
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
from slicc.symbols.Symbol import Symbol
+from slicc.symbols.State import WildcardState
class Transition(Symbol):
def __init__(self, table, machine, state, event, nextState, actions,
@@ -35,7 +36,19 @@
self.state = machine.states[state]
self.event = machine.events[event]
- self.nextState = machine.states[nextState]
+ if nextState == '*':
+ # check to make sure there is a getNextState function declared
+ found = False
+ for func in machine.functions:
+ if func.c_ident == 'getNextState':
+ found = True
+ break
+ if found == False:
+ fatal("Machine uses a wildcard transition without getNextState
defined")
+ self.nextState = WildcardState(machine.symtab,
+ '*', location)
+ else:
+ self.nextState = machine.states[nextState]
self.actions = [ machine.actions[a] for a in actions ]
self.request_types = [ machine.request_types[s] for s in request_types
]
self.resources = {}
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