Added rsh to BigInt library. Const Prop now works on rsh's on constants. #19.

4 files changed, 23 insertions, 14 deletions

diff --git a/src/main/stanza/bigint2.stanza b/src/main/stanza/bigint2.stanza
index d7376649..4657878a 100644
--- a/src/main/stanza/bigint2.stanza
+++ b/src/main/stanza/bigint2.stanza
@@ -75,7 +75,7 @@ public defn BigInt (d:Array<Int>, num-bits:Int) :
 
 public defmethod get (b:BigInt, index:Int) -> Int : 
    check-index(index)
-   if index > num-bits(b) : error("Bit index is too high")
+   if index >= num-bits(b) : error("Bit index is too high")
    val word-index = index / 32
    val bit-index = index % 32
    (d(b)[word-index] >> bit-index) & 1
@@ -147,12 +147,9 @@ public defn bit (b:BigInt, index:Int) -> BigInt :
    b*[0] = b[index]
    b*
 
-; For now, rsh does not change the number of bits
-public defn rsh-unsigned (b:BigInt, amount:Int) -> BigInt :
-   val b* = BigIntZero(num-bits(b))
-   for i in 0 to num-bits(b*) do :
-      b*[i] = b[i + amount]
-   b*
+public defn rsh (b:BigInt, amount:Int) -> BigInt : 
+   check-index(amount)
+   bits(b,num-bits(b), amount)
 
       
    
diff --git a/src/main/stanza/ir-parser.stanza b/src/main/stanza/ir-parser.stanza
index 71236795..13b23906 100644
--- a/src/main/stanza/ir-parser.stanza
+++ b/src/main/stanza/ir-parser.stanza
@@ -284,8 +284,8 @@ defsyntax firrtl :
             (t:UIntType) : 
                if (v as Int) < 0 : 
                   FPE(form, "UIntValue cannot be negative.")
-               UIntValue(BigIntLit(v as Int,32), width(t))
-            (t:SIntType) : SIntValue(BigIntLit(v as Int,32), width(t))
+               UIntValue(BigIntLit(v as Int), width(t))
+            (t:SIntType) : SIntValue(BigIntLit(v as Int), width(t))
 
       expterm = (?op:#sym(?es:#exp ... ?ints:#int ... ?rest ...)) :
          if not empty?(rest) :
diff --git a/src/main/stanza/ir-utils.stanza b/src/main/stanza/ir-utils.stanza
index 25006659..8f260e8c 100644
--- a/src/main/stanza/ir-utils.stanza
+++ b/src/main/stanza/ir-utils.stanza
@@ -128,7 +128,10 @@ public defn to-int (x:Long) -> Int :
    else : to-int(to-string(x))
 
 public defn req-num-bits (i: Int) -> Int :
-  max(1, ceil-log2(i + 1))
+  val i* = 
+     if i < 0 : ((-1 * i) - 1)
+     else : i
+  ceil-log2(i* + 1) + 1
 
 ;============== PRINTERS ===================================
 
diff --git a/src/main/stanza/passes.stanza b/src/main/stanza/passes.stanza
index 0470d521..a6239baa 100644
--- a/src/main/stanza/passes.stanza
+++ b/src/main/stanza/passes.stanza
@@ -1170,7 +1170,7 @@ defn expand-connect-indexed-stmt (s: Stmt,sh:HashTable<Symbol,Int>) -> Stmt :
                to-list $
                   for (i in 0 to false, l in locs(s)) stream : Conditionally(
                      info(s),
-                     equality(ref,UIntValue(BigIntLit(i,32),UnknownWidth())),
+                     equality(ref,UIntValue(BigIntLit(i),UnknownWidth())),
                      Connect(info(s),l,exp(s)),
                      EmptyStmt()
                   )
@@ -1184,7 +1184,7 @@ defn expand-connect-indexed-stmt (s: Stmt,sh:HashTable<Symbol,Int>) -> Stmt :
                to-list $
                   for (i in 1 to false, e in tail(exps(s))) stream : Conditionally(
                      info(s),
-                     equality(ref,UIntValue(BigIntLit(i,32),UnknownWidth())),
+                     equality(ref,UIntValue(BigIntLit(i),UnknownWidth())),
                      Connect(info(s),loc(s),e),
                      EmptyStmt()
                   )
@@ -1230,8 +1230,8 @@ public defmethod short-name (b:ExpandWhens) -> String : "expand-whens"
 
 ; ======== Expression Computation Library ===========
 
-val zero = UIntValue(BigIntLit(0,32),IntWidth(1))
-val one = UIntValue(BigIntLit(1,32),IntWidth(1))
+val zero = UIntValue(BigIntLit(0),IntWidth(1))
+val one = UIntValue(BigIntLit(1),IntWidth(1))
 
 defmethod equal? (e1:Expression,e2:Expression) -> True|False :
    match(e1,e2) :
@@ -2425,6 +2425,15 @@ defn const-prop-e (e:Expression) -> Expression :
    match(map(const-prop-e,e)) :
       (e:DoPrim) : 
          switch {op(e) == _} :
+            SHIFT-RIGHT-OP :
+               match(args(e)[0]) :
+                  (x:UIntValue) : 
+                     val b = rsh(value(x),consts(e)[0])
+                     UIntValue(b,width(type(e) as UIntType))
+                  (x:SIntValue) : 
+                     val b = rsh(value(x),consts(e)[0])
+                     SIntValue(b,width(type(e) as SIntType))
+                  (x) : e
             BITS-SELECT-OP : 
                match(args(e)[0]) :
                   (x:UIntValue) :