From 1903bc190deaa42e72560ed1a18ecef2f2f2efdc Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Thu, 2 Jul 2020 23:33:03 -0600
Subject: [PATCH] use unbounded integers

---
 src/Convert/SizeCast.hs                |  4 +---
 src/Convert/TypeOf.hs                  |  3 +--
 src/Language/SystemVerilog/AST/Expr.hs | 28 +++++++++-----------------
 test/basic/shift.sv                    | 20 ++++++++++++++++++
 4 files changed, 31 insertions(+), 24 deletions(-)

diff --git a/src/Convert/SizeCast.hs b/src/Convert/SizeCast.hs
index e9ec593..12ac644 100644
--- a/src/Convert/SizeCast.hs
+++ b/src/Convert/SizeCast.hs
@@ -66,9 +66,7 @@ traverseExprM =
                     where
                         str = (show size) ++ "'d"  ++ (show num)
                         size = s'
-                        num = if size >= 32
-                            then n' -- already read as 32 bits
-                            else n' `mod` (2 ^ s')
+                        num = n' `mod` (2 ^ s')
                 _ -> convertCastM (Number s) (Number n)
         convertExprM (orig @ (Cast (Right DimsFn{}) _)) =
             return orig
diff --git a/src/Convert/TypeOf.hs b/src/Convert/TypeOf.hs
index da4e340..42580cf 100644
--- a/src/Convert/TypeOf.hs
+++ b/src/Convert/TypeOf.hs
@@ -12,7 +12,6 @@
 module Convert.TypeOf (convert) where
 
 import Data.List (elemIndex)
-import Data.Int (Int32)
 import Data.Tuple (swap)
 import qualified Data.Map.Strict as Map
 
@@ -140,7 +139,7 @@ typeof (Repeat reps exprs) = return $ typeOfSize size
 typeof other = lookupTypeOf other
 
 -- determines the size and sign of a number literal
-parseNumber :: String -> (Int32, Signing)
+parseNumber :: String -> (Integer, Signing)
 parseNumber s =
     case elemIndex '\'' s of
         Nothing  -> (32, Signed)
diff --git a/src/Language/SystemVerilog/AST/Expr.hs b/src/Language/SystemVerilog/AST/Expr.hs
index 52f1603..114d2fc 100644
--- a/src/Language/SystemVerilog/AST/Expr.hs
+++ b/src/Language/SystemVerilog/AST/Expr.hs
@@ -27,9 +27,7 @@ module Language.SystemVerilog.AST.Expr
     ) where
 
 import Data.Bits (shiftL, shiftR)
-import Data.Int (Int32)
 import Data.List (intercalate)
-import Data.Word (Word32)
 import Numeric (readHex)
 import Text.Printf (printf)
 import Text.Read (readMaybe)
@@ -191,12 +189,12 @@ showExprOrRange :: ExprOrRange -> String
 showExprOrRange (Left  x) = show x
 showExprOrRange (Right x) = show x
 
-clog2Help :: Int32 -> Int32 -> Int32
+clog2Help :: Integer -> Integer -> Integer
 clog2Help p n = if p >= n then 0 else 1 + clog2Help (p*2) n
-clog2 :: Int32 -> Int32
+clog2 :: Integer -> Integer
 clog2 n = if n < 2 then 0 else clog2Help 1 n
 
-readNumber :: String -> Maybe Int32
+readNumber :: String -> Maybe Integer
 readNumber ('3' : '2' : '\'' : 'd' : rest) = readMaybe rest
 readNumber (            '\'' : 'd' : rest) = readMaybe rest
 readNumber ('3' : '2' : '\'' : 'h' : rest) =
@@ -207,13 +205,7 @@ readNumber ('\'' : 'h' : rest) =
     case readHex rest of
         [(v, _)] -> Just v
         _ -> Nothing
-readNumber n =
-    case readMaybe n of
-        Nothing -> Nothing
-        Just res ->
-            if show res == n
-                then Just res
-                else Nothing
+readNumber n = readMaybe n
 
 showUniOpPrec :: Expr -> ShowS
 showUniOpPrec (e @ UniOp{}) = (showParen True . shows) e
@@ -308,16 +300,14 @@ simplify (BinOp op e1 e2) =
                 (ShiftAL, Just x, Just y) -> Number $ show $ shiftL x (toInt y)
                 (ShiftAR, Just x, Just y) -> Number $ show $ shiftR x (toInt y)
                 (ShiftL , Just x, Just y) -> Number $ show $ shiftL x (toInt y)
-                (ShiftR , Just x, Just y) -> -- does not sign extend
-                    Number $ show $ toInt32 $ shiftR (toWord32 x) (toInt y)
+                (ShiftR , Just x, Just y) ->
+                    if x < 0 && y > 0
+                        then BinOp ShiftR (Number a) (Number b)
+                        else Number $ show $ shiftR x (toInt y)
                 _ -> BinOp op e1' e2'
             where
-                toInt :: Int32 -> Int
+                toInt :: Integer -> Int
                 toInt = fromIntegral
-                toWord32 :: Int32 -> Word32
-                toWord32 = fromIntegral
-                toInt32 :: Word32 -> Int32
-                toInt32 = fromIntegral
         (Add, BinOp Add e (Number a), Number b) ->
             case (readNumber a, readNumber b) of
                 (Just x, Just y) -> BinOp Add e $ Number $ show (x + y)
diff --git a/test/basic/shift.sv b/test/basic/shift.sv
index f747719..53b891d 100644
--- a/test/basic/shift.sv
+++ b/test/basic/shift.sv
@@ -26,5 +26,25 @@ module top;
         `TEST(2, 1);
         `TEST(2, 2);
         `TEST(2, 3);
+
+        `TEST(-8589934592, 0);
+        `TEST(-8589934592, 1);
+        `TEST(-8589934592, 2);
+        `TEST(-8589934592, 3);
+
+        `TEST(-8589934593, 0);
+        `TEST(-8589934593, 1);
+        `TEST(-8589934593, 2);
+        `TEST(-8589934593, 3);
+
+        `TEST(8589934592, 0);
+        `TEST(8589934592, 1);
+        `TEST(8589934592, 2);
+        `TEST(8589934592, 3);
+
+        `TEST(8589934593, 0);
+        `TEST(8589934593, 1);
+        `TEST(8589934593, 2);
+        `TEST(8589934593, 3);
     end
 endmodule