PackedArray conversion supports arbitrary endianness

src/Convert/PackedArray.hs

@@ -22,16 +22,13 @@
  - Note: We don't count usages with an index in expressions as such, as those
  - usages could be equivalently converted to range accesses with some added in
  - multiplication.
- -
- - TODO: This assumes that the first range index is the upper bound. We could
- - probably get around this with some cleverness in the generate block. I don't
- - think it's urgent to have support for "backwards" ranges.
  -}
 
 module Convert.PackedArray (convert) where
 
 import Control.Monad.State
 import Data.List (partition)
+import Data.Tuple (swap)
 import qualified Data.Set as Set
 import qualified Data.Map.Strict as Map
 
@@ -186,18 +183,20 @@ flattenModuleItem _ other = other
 -- produces `generate` items for creating an unflattened copy of the given
 -- flattened, packed array
 unflattener :: Bool -> Identifier -> (Type, Range) -> [GenItem]
-unflattener writeToFlatVariant arr (t, (majorHi, majorLo)) =
+unflattener writeToFlatVariant arr (t, major @ (majorHi, majorLo)) =
         [ GenModuleItem $ MIPackageItem $ Comment $ "sv2v packed-array-flatten unflattener for " ++ arr
         , GenModuleItem $ MIDecl $ Variable Local t arrUnflat [(majorHi, majorLo)] Nothing
         , GenModuleItem $ Genvar index
         , GenModuleItem $ MIDecl $ Variable Local (IntegerAtom TInteger Unspecified) (arrUnflat ++ "_repeater_index") [] Nothing
         , GenFor
             (index, majorLo)
-            (BinOp Le (Ident index) majorHi)
-            (index, AsgnOp Add, Number "1")
+            (ccExpr major
+                (BinOp Le (Ident index) majorHi)
+                (BinOp Ge (Ident index) majorHi))
+            (index, AsgnOp Add, ccExpr major (Number "1") (Number "-1"))
             (Just $ prefix "unflatten_" ++ arr)
             [ localparam startBit
-                (simplify $ BinOp Add majorLo
+                (simplify $ BinOp Add (ccExpr major majorLo majorHi)
                     (BinOp Mul (Ident index) size))
             , GenModuleItem $ (uncurry $ Assign Nothing) $
                 if not writeToFlatVariant
@@ -209,13 +208,23 @@ unflattener writeToFlatVariant arr (t, (majorHi, majorLo)) =
         startBit = prefix "_tmp_start_" ++ arr
         arrUnflat = prefix arr
         index = prefix "_tmp_index_" ++ arr
-        (minorHi, minorLo) = head $ snd $ typeRanges t
-        size = rangeSize (minorHi, minorLo)
+        minor = head $ snd $ typeRanges t
+        size = rangeSize $ ccRange minor minor (swap minor)
         localparam :: Identifier -> Expr -> GenItem
         localparam x v = GenModuleItem $ MIDecl $ Localparam (Implicit Unspecified []) x v
-        origRange = ( (BinOp Add (Ident startBit)
+        origRangeAg = ( (BinOp Add (Ident startBit)
                         (BinOp Sub size (Number "1")))
-                    , Ident startBit )
+                      , Ident startBit )
+        origRange = ccRange major origRangeAg (swap origRangeAg)
+
+ccExpr :: Range -> Expr -> Expr -> Expr
+ccExpr r e1 e2 = simplify $ Mux (uncurry (BinOp Ge) r) e1 e2
+
+ccRange :: Range -> Range -> Range -> Range
+ccRange r r1 r2 =
+    ( ccExpr r (fst r1) (fst r2)
+    , ccExpr r (snd r1) (snd r2)
+    )
 
 typeIsImplicit :: Type -> Bool
 typeIsImplicit (Implicit _ _) = True
@@ -232,13 +241,26 @@ flattenRanges rs =
         then rs'
         else error $ "flattenRanges on too small list: " ++ (show rs)
     where
-        (s1, e1) = head rs
-        (s2, e2) = head $ tail rs
+        r1 = head rs
+        r2 = head $ tail rs
+        rYY = flattenRangesHelp r1 r2
+        rYN = flattenRangesHelp r1 (swap r2)
+        rNY = flattenRangesHelp (swap r1) r2
+        rNN = flattenRangesHelp (swap r1) (swap r2)
+        rY = ccRange r2 rYY rYN
+        rN = ccRange r2 rNY rNN
+        rAg = ccRange r1 rY rN
+        r = ccRange r1 rAg (swap rAg)
+        rs' = (tail $ tail rs) ++ [r]
+
+flattenRangesHelp :: Range -> Range -> Range
+flattenRangesHelp (s1, e1) (s2, e2) =
+    (simplify upper, simplify lower)
+    where
         size1 = rangeSize (s1, e1)
         size2 = rangeSize (s2, e2)
-        upper = BinOp Add (BinOp Mul size1 size2) (BinOp Sub e1 (Number "1"))
-        r' = (simplify upper, e1)
-        rs' = (tail $ tail rs) ++ [r']
+        lower = BinOp Add e1 (BinOp Mul e2 size2)
+        upper = BinOp Add (BinOp Mul size1 size2) (BinOp Sub lower (Number "1"))
 
 rewriteModuleItem :: Info -> ModuleItem -> ModuleItem
 rewriteModuleItem info =

src/Language/SystemVerilog/AST/Expr.hs

@@ -90,6 +90,22 @@ showRange (h, l) = printf "[%s:%s]" (show h) (show l)
 -- basic expression simplfication utility to help us generate nicer code in the
 -- common case of ranges like `[FOO-1:0]`
 simplify :: Expr -> Expr
+simplify (Mux (BinOp Ge c1 c2) e1 e2) =
+    case (c1', c2') of
+        (Number a, Number b) ->
+            case (readMaybe a :: Maybe Int, readMaybe b :: Maybe Int) of
+                (Just x, Just y) ->
+                    if x >= y
+                        then e1
+                        else e2
+                _ -> nochange
+        _ -> nochange
+    where
+        c1' = simplify c1
+        c2' = simplify c2
+        e1' = simplify e1
+        e2' = simplify e2
+        nochange = Mux (BinOp Ge c1' c2') e1' e2'
 simplify (BinOp op e1 e2) =
     case (op, e1', e2') of
         (Add, Number "0", e) -> e
@@ -103,6 +119,10 @@ simplify (BinOp op e1 e2) =
                 (Sub, Just x, Just y) -> Number $ show (x - y)
                 (Mul, Just x, Just y) -> Number $ show (x * y)
                 _ -> BinOp op e1' e2'
+        (Add, BinOp Add e (Number a), Number b) ->
+            case (readMaybe a :: Maybe Int, readMaybe b :: Maybe Int) of
+                (Just x, Just y) -> BinOp Add e $ Number $ show (x + y)
+                _ -> BinOp op e1' e2'
         _ -> BinOp op e1' e2'
     where
         e1' = simplify e1

test/basic/enum_tb.v

+// intentionally empty

test/basic/flatten.sv

+`define CASE_A(name, dims) \
+module name(clock, in, out); \
+    input wire clock, in; \
+    output logic dims out; \
+    initial out[0] = 0; \
+    initial out[1] = 0; \
+    initial out[2] = 0; \
+    always @(posedge clock) begin \
+ \
+        out[2][4] = out[2][3]; \
+        out[2][3] = out[2][2]; \
+        out[2][2] = out[2][1]; \
+        out[2][1] = out[2][0]; \
+        out[2][0] = out[1][4]; \
+ \
+        out[1][4] = out[1][3]; \
+        out[1][3] = out[1][2]; \
+        out[1][2] = out[1][1]; \
+        out[1][1] = out[1][0]; \
+        out[1][0] = out[0][4]; \
+ \
+        out[0][4] = out[0][3]; \
+        out[0][3] = out[0][2]; \
+        out[0][2] = out[0][1]; \
+        out[0][1] = out[0][0]; \
+        out[0][0] = in; \
+ \
+    end \
+endmodule
+
+`CASE_A(A1, [2:0][4:0])
+`CASE_A(A2, [0:2][0:4])
+`CASE_A(A3, [0:2][4:0])
+`CASE_A(A4, [2:0][0:4])
+
+`define CASE_B(name, dims) \
+module name(clock, in, out); \
+    input wire clock, in; \
+    output logic dims out; \
+    initial out[1] = 0; \
+    initial out[2] = 0; \
+    initial out[3] = 0; \
+    always @(posedge clock) begin \
+ \
+        out[3][5] = out[3][4]; \
+        out[3][4] = out[3][3]; \
+        out[3][3] = out[3][2]; \
+        out[3][2] = out[3][1]; \
+        out[3][1] = out[2][5]; \
+ \
+        out[2][5] = out[2][4]; \
+        out[2][4] = out[2][3]; \
+        out[2][3] = out[2][2]; \
+        out[2][2] = out[2][1]; \
+        out[2][1] = out[1][5]; \
+ \
+        out[1][5] = out[1][4]; \
+        out[1][4] = out[1][3]; \
+        out[1][3] = out[1][2]; \
+        out[1][2] = out[1][1]; \
+        out[1][1] = in; \
+ \
+    end \
+endmodule
+
+`CASE_B(B1, [3:1][5:1])
+`CASE_B(B2, [1:3][1:5])
+`CASE_B(B3, [1:3][5:1])
+`CASE_B(B4, [3:1][1:5])
+
+`define CASE_C(name, dims) \
+module name(clock, in, out); \
+    input wire clock, in; \
+    output logic dims out; \
+    initial out[2] = 0; \
+    initial out[3] = 0; \
+    initial out[4] = 0; \
+    always @(posedge clock) begin \
+ \
+        out[4][6] = out[4][5]; \
+        out[4][5] = out[4][4]; \
+        out[4][4] = out[4][3]; \
+        out[4][3] = out[4][2]; \
+        out[4][2] = out[3][6]; \
+ \
+        out[3][6] = out[3][5]; \
+        out[3][5] = out[3][4]; \
+        out[3][4] = out[3][3]; \
+        out[3][3] = out[3][2]; \
+        out[3][2] = out[2][6]; \
+ \
+        out[2][6] = out[2][5]; \
+        out[2][5] = out[2][4]; \
+        out[2][4] = out[2][3]; \
+        out[2][3] = out[2][2]; \
+        out[2][2] = in; \
+ \
+    end \
+endmodule
+
+`CASE_C(C1, [4:2][6:2])
+`CASE_C(C2, [2:4][2:6])
+`CASE_C(C3, [2:4][6:2])
+`CASE_C(C4, [4:2][2:6])

test/basic/flatten.v

+// iverilog supports multi-dimensional packed arrays
+`include "flatten.sv"

test/basic/flatten_tb.v

+`define FOO(tag) \
+    wire [14:0] tag``one_out, tag``two_out, tag``thr_out, tag``fou_out; \
+    tag``1 tag``one(.clock(clock), .in(in), .out(tag``one_out)); \
+    tag``2 tag``two(.clock(clock), .in(in), .out(tag``two_out)); \
+    tag``3 tag``thr(.clock(clock), .in(in), .out(tag``thr_out)); \
+    tag``4 tag``fou(.clock(clock), .in(in), .out(tag``fou_out)); \
+    initial begin \
+        $monitor(`"tag", $time, ": %h %15b %15b %15b %15b", in, \
+            tag``one_out, tag``two_out, tag``thr_out, tag``fou_out); \
+    end
+
+module top;
+    reg clock, in;
+
+    initial begin
+        clock = 1;
+        forever #1 clock = ~clock;
+    end
+
+    integer i;
+    localparam [20:0] pattern = 20'b01101100001010101100;
+    initial begin
+        for (i = 0; i < 20; i++) begin
+            in = pattern[i];
+            #2;
+        end
+        $finish;
+    end
+
+    `FOO(A)
+    `FOO(B)
+    `FOO(C)
+
+endmodule

test/basic/run.sh

 #!/bin/sh
-NO_SEPARATE_TBS=1
 source ../lib/runner.sh