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authorDavid Hashe <david.hashe@amd.com>2015-07-20 09:15:18 -0500
committerDavid Hashe <david.hashe@amd.com>2015-07-20 09:15:18 -0500
commitee0d414fa8dac2371b439778374ec585b358e549 (patch)
tree94d386b04002226fcf816c64c589d544e67504af /src/mem/slicc
parent6a288d9de3422024b9e99caa8b3717d98e467314 (diff)
downloadgem5-ee0d414fa8dac2371b439778374ec585b358e549.tar.xz
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 (limited to 'src/mem/slicc')
-rw-r--r--src/mem/slicc/parser.py9
-rw-r--r--src/mem/slicc/symbols/State.py8
-rw-r--r--src/mem/slicc/symbols/StateMachine.py13
-rw-r--r--src/mem/slicc/symbols/Transition.py15
4 files changed, 40 insertions, 5 deletions
diff --git a/src/mem/slicc/parser.py b/src/mem/slicc/parser.py
index 10dd99ece..1ce8bf1bd 100644
--- a/src/mem/slicc/parser.py
+++ b/src/mem/slicc/parser.py
@@ -278,7 +278,7 @@ class SLICC(Grammar):
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 @@ class SLICC(Grammar):
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 @@ class SLICC(Grammar):
"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 --git a/src/mem/slicc/symbols/State.py b/src/mem/slicc/symbols/State.py
index 123693256..164c585f6 100644
--- a/src/mem/slicc/symbols/State.py
+++ b/src/mem/slicc/symbols/State.py
@@ -30,5 +30,13 @@ from slicc.symbols.Symbol import Symbol
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 --git a/src/mem/slicc/symbols/StateMachine.py b/src/mem/slicc/symbols/StateMachine.py
index 174d66e0f..8a4d7d9b5 100644
--- a/src/mem/slicc/symbols/StateMachine.py
+++ b/src/mem/slicc/symbols/StateMachine.py
@@ -1310,8 +1310,17 @@ ${ident}_Controller::doTransitionWorker(${ident}_Event event,
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 --git a/src/mem/slicc/symbols/Transition.py b/src/mem/slicc/symbols/Transition.py
index 901d4a0e8..9ecd6c54b 100644
--- a/src/mem/slicc/symbols/Transition.py
+++ b/src/mem/slicc/symbols/Transition.py
@@ -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 @@ class Transition(Symbol):
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 = {}