gram.core.bankmachine: Remove unused local variables in BankMachine

[gram.git] / gram / compat.py

diff --git a/gram/compat.py b/gram/compat.py
index e049dcd0e4a014209b1b6c4b02994029755e1215..c05300650fdc7d9cd8956a7715e2abfdd0e6c5ab 100644 (file)
--- a/gram/compat.py
+++ b/gram/compat.py
@@ -7,11 +7,16 @@ from nmigen import tracer
 from nmigen.compat import Case
 from nmigen.back.pysim import *
 
-__ALL__ = ["delayed_enter", "RoundRobin", "Timeline", "CSRPrefixProxy"]
+__ALL__ = ["delayed_enter", "Timeline", "CSRPrefixProxy"]
 
 
 def delayed_enter(m, src, dst, delay):
-    assert delay > 0
+    if not isinstance(m, Module):
+        raise ValueError("m must be a module object, not {!r}".format(m))
+    if not isinstance(delay, int):
+        raise ValueError("Delay must be an integer, not {!r}".format(delay))
+    if delay < 1:
+        raise ValueError("Delay must be at least one cycle, not {!r}".format(delay))
 
     for i in range(delay):
         if i == 0:
@@ -27,44 +32,6 @@ def delayed_enter(m, src, dst, delay):
         with m.State(statename):
             m.next = deststate
 
-class RoundRobin(Elaboratable):
-    """A round-robin scheduler. (HarryHo90sHK)
-    Parameters
-    ----------
-    n : int
-        Maximum number of requests to handle.
-    Attributes
-    ----------
-    request : Signal(n)
-        Signal where a '1' on the i-th bit represents an incoming request from the i-th device.
-    grant : Signal(range(n))
-        Signal that equals to the index of the device which is currently granted access.
-    stb : Signal()
-        Strobe signal to enable granting access to the next device requesting. Externally driven.
-    """
-
-    def __init__(self, n):
-        self.n = n
-        self.request = Signal(n)
-        self.grant = Signal(range(n))
-        self.stb = Signal()
-
-    def elaborate(self, platform):
-        m = Module()
-
-        with m.If(self.stb):
-            with m.Switch(self.grant):
-                for i in range(self.n):
-                    with m.Case(i):
-                        for j in reversed(range(i+1, i+self.n)):
-                            # If i+1 <= j < n, then t == j;     (after i)
-                            # If n <= j < i+n, then t == j - n  (before i)
-                            t = j % self.n
-                            with m.If(self.request[t]):
-                                m.d.sync += self.grant.eq(t)
-
-        return m
-
 
 class Timeline(Elaboratable):
     def __init__(self, events):