From 0c3193659002fd6d01350d54a260823b65ce8678 Mon Sep 17 00:00:00 2001
From: Zachary Snow <zach@zachjs.com>
Date: Thu, 10 Dec 2020 14:52:43 -0700
Subject: [PATCH] maintain explicit padding in unsized number literals

---
 src/Language/SystemVerilog/AST/Number.hs | 18 +++++++++++-------
 test/lex/number.sv                       | 14 ++++++++++++++
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/src/Language/SystemVerilog/AST/Number.hs b/src/Language/SystemVerilog/AST/Number.hs
index e1941e8..c25f01b 100644
--- a/src/Language/SystemVerilog/AST/Number.hs
+++ b/src/Language/SystemVerilog/AST/Number.hs
@@ -78,7 +78,7 @@ parseNumber' str =
             if rawSize /= 0 then
                 rawSize
             else if maybeBase /= Nothing then
-                negate $ max 32 (bitsPerDigit * numDigits)
+                negate $ bitsPerDigit * numDigits
             else
                 -32
         bitsPerDigit = bits $ baseSize base - 1
@@ -170,7 +170,11 @@ baseSize Hex    = 16
 numberBitLength :: Number -> Integer
 numberBitLength UnbasedUnsized{} = 32
 numberBitLength (Decimal size _ _) = fromIntegral $ abs size
-numberBitLength (Based size _ _ _ _) = fromIntegral $ abs size
+numberBitLength (Based size _ _ _ _) =
+    fromIntegral $
+    if size < 0
+        then max 32 $ negate size
+        else size
 
 -- get whether or not a number is signed
 numberIsSized :: Number -> Bool
@@ -226,16 +230,16 @@ instance Show Number where
             sizeStr = if size > 0 then show size else ""
             signedStr = if signed then "s" else ""
             [baseCh] = show base
-            valueStr = showBasedDigits (baseSize base) size value kinds
+            valueStr = showBasedDigits signed (baseSize base) size value kinds
 
-showBasedDigits :: Int -> Int -> Integer -> Integer -> String
-showBasedDigits base size values kinds =
+showBasedDigits :: Bool -> Int -> Int -> Integer -> Integer -> String
+showBasedDigits signed base size values kinds =
     if numDigits > sizeDigits then
         error $ "invalid based literal digits: "
             ++ show (base, size, values, kinds, numDigits, sizeDigits)
-    else if size < -32 then
+    else if size < -32 || (size < 0 && signed) then
         padList '0' sizeDigits digits
-    else if leadingXZ && size < 0 then
+    else if leadingXZ && size < 0 && sizeDigits == numDigits then
         removeExtraPadding digits
     else if leadingXZ || (256 >= size && size > 0) then
         padList '0' sizeDigits digits
diff --git a/test/lex/number.sv b/test/lex/number.sv
index fb8a3a8..6b900a4 100644
--- a/test/lex/number.sv
+++ b/test/lex/number.sv
@@ -37,5 +37,19 @@ module top;
         `TEST('h01xz01xz) `TEST('h101xz01xz)
         `TEST(36'h01xz01xz) `TEST(37'h01xz01xz)
         `TEST(36'hb01xz01xz) `TEST(37'hb01xz01xz)
+
+        `TEST('sb0) `TEST('sb1)
+        `TEST('sb00) `TEST('sb10) `TEST('sb01) `TEST('sb11)
+        `TEST('sb000) `TEST('sb001) `TEST('sb010) `TEST('sb011)
+        `TEST('sb100) `TEST('sb101) `TEST('sb110) `TEST('sb111)
+
+        `TEST('b0) `TEST('b1)
+        `TEST('b00) `TEST('b10) `TEST('b01) `TEST('b11)
+        `TEST('b000) `TEST('b001) `TEST('b010) `TEST('b011)
+        `TEST('b100) `TEST('b101) `TEST('b110) `TEST('b111)
+
+        `TEST('b0x) `TEST('sb0x) `TEST('b0z) `TEST('sb0z)
+        `TEST('o0x) `TEST('so0x) `TEST('o0z) `TEST('so0z)
+        `TEST('h0x) `TEST('sh0x) `TEST('h0z) `TEST('sh0z)
     end
 endmodule