techmap: fix shiftx2mux decomposition

diff --git a/techlibs/common/techmap.v b/techlibs/common/techmap.v
index be6530eb4367118f768ee1fd2ce39321e65fe400..ecf4d5dc5466b87c031ef52f7feb014da09ea43e 100644 (file)
--- a/techlibs/common/techmap.v
+++ b/techlibs/common/techmap.v
@@ -149,16 +149,14 @@ module _90_shift_shiftx (A, B, Y);
                        _TECHMAP_CONSTVAL_B_[CLOG2_Y_WIDTH-1:0] == {CLOG2_Y_WIDTH{1'b0}}) begin
                        // Halve the size of $shift/$shiftx by $mux-ing A according to
                        //   the LSB of B, after discarding the zeroed bits
-                       localparam len = 2**(B_WIDTH-1);
                        localparam Y_WIDTH2 = 2**CLOG2_Y_WIDTH;
-                       wire [len-1:0] T, F, AA;
-                       wire [(A_WIDTH+Y_WIDTH2*2):0] Apad = {{Y_WIDTH2*2{extbit}}, A};
+                       localparam entries = (A_WIDTH+Y_WIDTH-1)/Y_WIDTH2;
+                       localparam len = Y_WIDTH2 * ((entries+1)/2);
+                       wire [len-1:0] AA;
+                       wire [(A_WIDTH+Y_WIDTH2+Y_WIDTH-1)-1:0] Apad = {{(Y_WIDTH2+Y_WIDTH-1){extbit}}, A};
                        genvar i;
-                       for (i = 0; i < A_WIDTH; i=i+Y_WIDTH2*2) begin
-                               assign F[i/2 +: Y_WIDTH2] = A[i +: Y_WIDTH2];
-                               assign T[i/2 +: Y_WIDTH2] = Apad[i+Y_WIDTH2 +: Y_WIDTH2];
-                               assign AA[i/2 +: Y_WIDTH2] = B[CLOG2_Y_WIDTH] ? T[i/2 +: Y_WIDTH2] : F[i/2 +: Y_WIDTH2];
-                       end
+                       for (i = 0; i < A_WIDTH; i=i+Y_WIDTH2*2)
+                               assign AA[i/2 +: Y_WIDTH2] = B[CLOG2_Y_WIDTH] ? Apad[i+Y_WIDTH2 +: Y_WIDTH2] : Apad[i +: Y_WIDTH2];
                        wire [B_WIDTH-2:0] BB = {B[B_WIDTH-1:CLOG2_Y_WIDTH+1], {CLOG2_Y_WIDTH{1'b0}}};
                        if (_TECHMAP_CELLTYPE_ == "$shift")
                                $shift #(.A_SIGNED(A_SIGNED), .B_SIGNED(B_SIGNED), .A_WIDTH(len), .B_WIDTH(B_WIDTH-1), .Y_WIDTH(Y_WIDTH)) _TECHMAP_REPLACE_ (.A(AA), .B(BB), .Y(Y));