Fixed bug where firrtl was incorrectly judging the width of a bigint. #36 #37.

7 files changed, 65 insertions, 17 deletions

diff --git a/src/main/stanza/bigint2.stanza b/src/main/stanza/bigint2.stanza
index 64c587ee..bc2e9f36 100644
--- a/src/main/stanza/bigint2.stanza
+++ b/src/main/stanza/bigint2.stanza
@@ -17,15 +17,27 @@ defn as-digit (c: Char) -> Int :
 
 defn num-words (b:BigInt) : length(d(b))
 
+defn shamt (c:Char) : 
+   if c == 'b': 1 
+   else if c == 'h': 4 
+   else: error("Unsupported BigInt base.")
+
 defn req-words (num-bits:Int) : (num-bits + word-size - 1) / word-size
 
 defn to-hex (b:BigInt) -> String :
    defn as-hex (i: Int) -> String : substring(all-digits,i,i + 1)
    var li = List<String>()
+   val tib = num-bits(b) % 4
    for i in 0 to num-bits(b) by 4 do :
       val word-index = i / 32
       val bit-index = i % 32
-      val digit = (d(b)[word-index] >> (bit-index)) & 15 
+      var mask = 15
+      
+      val digit = 
+         if (i + tib) == num-bits(b) :
+            (d(b)[word-index] >> bit-index) & (pow(2,tib) - 1)
+         else :
+            (d(b)[word-index] >> bit-index) & 15 
       li = List(as-hex(digit),li)
    var saw-not-zero? = false
    val li* = Vector<String>()
@@ -93,6 +105,16 @@ public defmethod to-string (b:BigInt) : to-hex(b)
 public defmethod print (o:OutputStream, b:BigInt) :
    print(o, to-string(b))
 
+public defn req-num-bits (b:BigInt) -> Int :
+   var msb = 0
+   var seen? = false
+   for i in 0 to num-bits(b) do :
+      val index = num-bits(b) - 1 - i
+      if b[index] != 0 and seen? == false :
+         msb = index
+         seen? = true
+   msb + 1
+
 public defn BigIntZero (num-bits:Int) -> BigInt :
    val num-words = (num-bits + word-size - 1) / word-size
    val d = Array<Int>(num-words)
@@ -109,19 +131,17 @@ public defn BigIntLit (data:Int, num-bits:Int) -> BigInt :
    b
 
 public defn BigIntLit (data:String) -> BigInt :
-  val base    = data[0]
-  val shamt   = if base == 'b': 1 else if base == 'h': 4 else: error("Unsupported BigInt base.")
-  val digits  = substring(data, 1)
-  val num-bits = length(digits) * shamt
-  BigIntLit(digits,shamt,num-bits)
+  val num-bits = (length(data) - 1) * shamt(data[0])
+  BigIntLit(data,num-bits)
 
-public defn BigIntLit (digits:String, shamt:Int, num-bits:Int) -> BigInt :
+public defn BigIntLit (data:String, num-bits:Int) -> BigInt :
   val lit     = BigIntZero(num-bits)
+  val digits  = substring(data, 1)
   ;; println-all(["BASE " base " SHAMT " shamt " DIGITS " digits])
   for i in 0 to num-words(lit) do :
     d(lit)[i] = 0
   for i in 0 to length(digits) do :
-    val off   = (length(digits) - 1 - i) * shamt
+    val off   = (length(digits) - 1 - i) * shamt(data[0])
     val wi    = off / word-size
     val bi    = off % word-size
     d(lit)[wi]   = d(lit)[wi] | (as-digit(digits[i]) << bi)
diff --git a/src/main/stanza/errors.stanza b/src/main/stanza/errors.stanza
index fd3dfc2a..69073f9f 100644
--- a/src/main/stanza/errors.stanza
+++ b/src/main/stanza/errors.stanza
@@ -918,14 +918,14 @@ public defn check-width (c:Circuit) -> Circuit :
             (e:UIntValue) : 
                match(width(e)) :
                   (w:LongWidth) : 
-                     if max(to-long(1),to-long(num-bits(value(e)) - 1)) > width(w) : 
+                     if max(to-long(1),to-long(req-num-bits(value(e)) - 1)) > width(w) : 
                         add(errors,WidthTooSmall(info,to-string(value(e))))
                   (w) : add(errors,UninferredWidth(info))
                check-width-w(info,width(e))
             (e:SIntValue) : 
                match(width(e)) :
                   (w:LongWidth) : 
-                     if to-long(num-bits(value(e))) > width(w) : 
+                     if to-long(req-num-bits(value(e))) > width(w) : 
                         add(errors,WidthTooSmall(info,to-string(value(e))))
                   (w) : add(errors,UninferredWidth(info))
                check-width-w(info,width(e))
diff --git a/src/main/stanza/ir-parser.stanza b/src/main/stanza/ir-parser.stanza
index d3d9c379..f81777f5 100644
--- a/src/main/stanza/ir-parser.stanza
+++ b/src/main/stanza/ir-parser.stanza
@@ -277,9 +277,24 @@ defsyntax firrtl :
       
       ;Prefix Operators
       expterm = (?t:#inttype(?v:#string)) :
+         val b = BigIntLit(v as String)
          match(t) :
-            (t:UIntType) : UIntValue(BigIntLit(v as String), width(t))
-            (t:SIntType) : SIntValue(BigIntLit(v as String), width(t))
+            (t:UIntType) : 
+               match(width(t)) :
+                  (w:LongWidth) :
+                     if to-long(max(1,(req-num-bits(b) - 1))) > width(w) :
+                        FPE(form, "Width too small for UIntValue.")
+                     UIntValue(b, w)
+                  (w) :
+                     UIntValue(b, w)
+            (t:SIntType) : 
+               match(width(t)) :
+                  (w:LongWidth) :
+                     if to-long(req-num-bits(b)) > width(w) :
+                        FPE(form, "Width too small for SIntValue.")
+                     SIntValue(b, w)
+                  (w) :
+                     SIntValue(b, w)
 
       expterm = (?t:#inttype(?v:#int$)) :
          match(t) :
@@ -288,7 +303,7 @@ defsyntax firrtl :
                   FPE(form, "UIntValue cannot be negative.")
                match(width(t)) :
                   (w:LongWidth) : 
-                     UIntValue(BigIntLit(v as Int,to-int(width(w))),w)
+                     UIntValue(BigIntLit(v as Int,to-int(width(w)) + 1),w)
                   (w) : 
                      val num-bits = req-num-bits(v as Int)
                      UIntValue(BigIntLit(v as Int,num-bits), LongWidth(max(1,num-bits - 1)))
diff --git a/src/main/stanza/ir-utils.stanza b/src/main/stanza/ir-utils.stanza
index 0c3140ed..a234ff81 100644
--- a/src/main/stanza/ir-utils.stanza
+++ b/src/main/stanza/ir-utils.stanza
@@ -500,6 +500,14 @@ public defn merge!<?K,?V> (a:HashTable<?K,?V>, b:HashTable<K,V>) :
    for e in b do :
       a[key(e)] = value(e)
 
+public defn pow (x:Int,y:Int) -> Int :
+   var x* = 1
+   var y* = y
+   while y* != 0 :
+      x* = times(x*,x)
+      y* = minus(y*,1)
+   x*
+
 public defn pow (x:Long,y:Long) -> Long :
    var x* = to-long(1)
    var y* = y
diff --git a/src/main/stanza/passes.stanza b/src/main/stanza/passes.stanza
index 8a03fb10..fead9ac2 100644
--- a/src/main/stanza/passes.stanza
+++ b/src/main/stanza/passes.stanza
@@ -1983,14 +1983,14 @@ defn gen-constraints (m:Module, h:HashTable<Symbol,Type>, v:Vector<WGeq>) -> Mod
             match(width(e)) :
                (w:UnknownWidth) : 
                   val w* = VarWidth(firrtl-gensym(`w,width-name-hash))
-                  add(v,WGeq(w*,LongWidth(max(1,num-bits(value(e)) - 1))))
+                  add(v,WGeq(w*,LongWidth(max(1,req-num-bits(value(e)) - 1))))
                   UIntValue(value(e),w*)
                (w) : e
          (e:SIntValue) : 
             match(width(e)) :
                (w:UnknownWidth) : 
                   val w* = VarWidth(firrtl-gensym(`w,width-name-hash))
-                  add(v,WGeq(w*,LongWidth(num-bits(value(e)))))
+                  add(v,WGeq(w*,LongWidth(req-num-bits(value(e)))))
                   SIntValue(value(e),w*)
                (w) : e
          (e) : e
diff --git a/test/errors/width/Conservative.fir b/test/errors/width/Conservative.fir
new file mode 100644
index 00000000..43aa648f
--- /dev/null
+++ b/test/errors/width/Conservative.fir
@@ -0,0 +1,6 @@
+; RUN: firrtl -i %s -o %s.v -X verilog -p ciwT 2>&1 | tee %s.out | FileCheck %s
+; CHECK: Width too small for UIntValue.
+
+circuit Top : 
+  module Top : 
+    node bar = UInt<1>("h1111")
diff --git a/test/errors/width/SmallWidth.fir b/test/errors/width/SmallWidth.fir
index 9e26699e..0ee60ec0 100644
--- a/test/errors/width/SmallWidth.fir
+++ b/test/errors/width/SmallWidth.fir
@@ -1,6 +1,5 @@
 ; RUN: firrtl -i %s -o %s.v -X verilog -p ciwT 2>&1 | tee %s.out | FileCheck %s
-; CHECK: Width too small for constant "h121".
-; CHECK: Width too small for constant "h13333".
+; CHECK: Width too small for UIntValue.
 
 circuit Top : 
   module Top :