xilinx: Improve flip-flop handling.

This adds support for infering more kinds of flip-flops:

- FFs with async set/reset and clock enable
- FFs with sync set/reset
- FFs with sync set/reset and clock enable

Some passes have been moved (and some added) in order for dff2dffs to
work correctly.

This gives us complete coverage of Virtex 6+ and Spartan 6 flip-flop
capabilities (though not latch capabilities).  Older FPGAs also support
having both a set and a reset input, which will be handled at a later
data.

1 files changed, 78 insertions, 16 deletions

diff --git a/techlibs/xilinx/xc7_ff_map.v b/techlibs/xilinx/xc7_ff_map.v
index 32ca9f560..2bd874457 100644
--- a/techlibs/xilinx/xc7_ff_map.v
+++ b/techlibs/xilinx/xc7_ff_map.v
@@ -37,6 +37,8 @@
 
 `ifndef _NO_FFS
 
+// No reset.
+
 module  \$_DFF_N_   (input D, C, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
   FDRE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .R(1'b0));
@@ -48,6 +50,8 @@ module  \$_DFF_P_   (input D, C, output Q);
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
 
+// No reset, enable.
+
 module  \$_DFFE_NP_ (input D, C, E, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
   FDRE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E),    .R(1'b0));
@@ -59,47 +63,103 @@ module  \$_DFFE_PP_ (input D, C, E, output Q);
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
 
-module  \$_DFF_NN0_ (input D, C, R, output Q);
+// Async reset.
+
+module  \$_DFF_NP0_ (input D, C, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDCE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR(!R));
+  FDCE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
-module  \$_DFF_NP0_ (input D, C, R, output Q);
+module  \$_DFF_PP0_ (input D, C, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDCE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR( R));
+  FDCE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
-module  \$_DFF_PN0_ (input D, C, R, output Q);
+
+module  \$_DFF_NP1_ (input D, C, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDCE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR(!R));
+  FDPE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .PRE( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
-module  \$_DFF_PP0_ (input D, C, R, output Q);
+module  \$_DFF_PP1_ (input D, C, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDCE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .CLR( R));
+  FDPE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .PRE( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
 
-module  \$_DFF_NN1_ (input D, C, R, output Q);
+// Async reset, enable.
+
+module  \$__DFFE_NP0 (input D, C, E, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDPE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .PRE(!R));
+  FDCE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .CLR( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
-module  \$_DFF_NP1_ (input D, C, R, output Q);
+module  \$__DFFE_PP0 (input D, C, E, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDPE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .PRE( R));
+  FDCE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .CLR( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
-module  \$_DFF_PN1_ (input D, C, R, output Q);
+
+module  \$__DFFE_NP1 (input D, C, E, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDPE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .PRE(!R));
+  FDPE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .PRE( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
-module  \$_DFF_PP1_ (input D, C, R, output Q);
+module  \$__DFFE_PP1 (input D, C, E, R, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
-  FDPE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .PRE( R));
+  FDPE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .PRE( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+
+// Sync reset.
+
+module  \$__DFFS_NP0_ (input D, C, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDRE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .R( R));
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
+module  \$__DFFS_PP0_ (input D, C, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDRE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .R( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+
+module  \$__DFFS_NP1_ (input D, C, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDSE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .S( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+module  \$__DFFS_PP1_ (input D, C, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDSE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(1'b1), .S( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+
+// Sync reset, enable.
+
+module  \$__DFFSE_NP0 (input D, C, E, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDRE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .R( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+module  \$__DFFSE_PP0 (input D, C, E, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDRE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .R( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+
+module  \$__DFFSE_NP1 (input D, C, E, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDSE_1 #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .S( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+module  \$__DFFSE_PP1 (input D, C, E, R, output Q);
+  parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
+  FDSE   #(.INIT(_TECHMAP_WIREINIT_Q_)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(E), .S( R));
+  wire _TECHMAP_REMOVEINIT_Q_ = 1;
+endmodule
+
+// Latches (no reset).
 
 module  \$_DLATCH_N_ (input E, D, output Q);
   parameter _TECHMAP_WIREINIT_Q_ = 1'bx;
@@ -112,5 +172,7 @@ module  \$_DLATCH_P_ (input E, D, output Q);
   wire _TECHMAP_REMOVEINIT_Q_ = 1;
 endmodule
 
+// Latches with reset (TODO).
+
 `endif