From: Eddie Hung <eddieh@ece.ubc.ca>
Date: Thu, 14 Mar 2019 16:38:42 +0000 (-0700)
Subject: Reverse bits in INIT parameter for Xilinx, since MSB is shifted first
X-Git-Tag: yosys-0.9~171^2~58
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e7ef7fa443c0b7c7ec9e4bbb15893053aed8c3ce;p=yosys.git

Reverse bits in INIT parameter for Xilinx, since MSB is shifted first
---

diff --git a/techlibs/xilinx/cells_map.v b/techlibs/xilinx/cells_map.v
index 0c5c5a26f..69f8b85f4 100644
--- a/techlibs/xilinx/cells_map.v
+++ b/techlibs/xilinx/cells_map.v
@@ -23,6 +23,19 @@ module \$__SHREG_ (input C, input D, input E, output Q);
   parameter CLKPOL = 1;
   parameter ENPOL = 2;
   wire CE;
+
+  // shregmap's INIT parameter shifts out LSB first;
+  // however Xilinx expects MSB first
+  function [DEPTH-1:0] brev;
+    input [DEPTH-1:0] din;
+    integer i;
+    begin
+      for (i = 0; i < DEPTH; i=i+1)
+        brev[i] = din[DEPTH-1-i];
+    end
+  endfunction
+  localparam [DEPTH-1:0] INIT_R = brev(INIT);
+
   generate
     if (ENPOL == 0)
       assign CE = ~E;
@@ -31,28 +44,31 @@ module \$__SHREG_ (input C, input D, input E, output Q);
     else
       assign CE = 1'b1;
     if (DEPTH == 1) begin
-        FDRE #(.INIT(INIT), .IS_C_INVERTED(~CLKPOL[0]), .IS_D_INVERTED(|0), .IS_R_INVERTED(|0)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(CE), .R(1'b0));
+        if (CLKPOL)
+            FDRE #(.INIT(INIT_R)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(CE), .R(1'b0));
+        else
+            FDRE_1 #(.INIT(INIT_R)) _TECHMAP_REPLACE_ (.D(D), .Q(Q), .C(C), .CE(CE), .R(1'b0));
     end else
     if (DEPTH <= 16) begin
       localparam [3:0] A = DEPTH - 1;
-      SRL16E #(.INIT(INIT), .IS_CLK_INVERTED(~CLKPOL[0])) _TECHMAP_REPLACE_ (.A0(A[0]), .A1(A[1]), .A2(A[2]), .A3(A[3]), .CE(CE), .CLK(C), .D(D), .Q(Q));
+      SRL16E #(.INIT(INIT_R), .IS_CLK_INVERTED(~CLKPOL[0])) _TECHMAP_REPLACE_ (.A0(A[0]), .A1(A[1]), .A2(A[2]), .A3(A[3]), .CE(CE), .CLK(C), .D(D), .Q(Q));
     end else
     if (DEPTH > 17 && DEPTH <= 32) begin
-      SRLC32E #(.INIT(INIT), .IS_CLK_INVERTED(~CLKPOL[0])) _TECHMAP_REPLACE_ (.A(DEPTH-1), .CE(CE), .CLK(C), .D(D), .Q(Q));
+      SRLC32E #(.INIT(INIT_R), .IS_CLK_INVERTED(~CLKPOL[0])) _TECHMAP_REPLACE_ (.A(DEPTH-1), .CE(CE), .CLK(C), .D(D), .Q(Q));
     end else
     if (DEPTH > 33 && DEPTH <= 64) begin
       wire T0, T1, T2;
       localparam [5:0] A = DEPTH-1;
-      SRLC32E #(.INIT(INIT[32-1:0]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_0 (.A(A[4:0]), .CE(CE), .CLK(C), .D(D), .Q(T0), .Q31(T1));
-      \$__SHREG_ #(.DEPTH(DEPTH-32), .INIT(INIT[DEPTH-1:32]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_1 (.C(C), .D(T1), .E(E), .Q(T2));
+      SRLC32E #(.INIT(INIT_R[32-1:0]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_0 (.A(A[4:0]), .CE(CE), .CLK(C), .D(D), .Q(T0), .Q31(T1));
+      \$__SHREG_ #(.DEPTH(DEPTH-32), .INIT(INIT[DEPTH-32-1:0]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_1 (.C(C), .D(T1), .E(E), .Q(T2));
       MUXF7 fpga_mux_0 (.O(Q), .I0(T0), .I1(T2), .S(A[5]));
     end else
     if (DEPTH > 65 && DEPTH <= 96) begin
       localparam [6:0] A = DEPTH-1;
       wire T0, T1, T2, T3, T4, T5, T6;
-      SRLC32E #(.INIT(INIT[32-1:0]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_0 (.A(A[4:0]), .CE(CE), .CLK(C), .D(D), .Q(T0), .Q31(T1));
-      SRLC32E #(.INIT(INIT[64-1:32]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_1 (.A(A[4:0]), .CE(CE), .CLK(C), .D(T1), .Q(T2), .Q31(T3));
-      \$__SHREG_ #(.DEPTH(DEPTH-64), .INIT(INIT[DEPTH-1:64]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_2 (.C(C), .D(T3), .E(E), .Q(T4));
+      SRLC32E #(.INIT(INIT_R[32-1:0]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_0 (.A(A[4:0]), .CE(CE), .CLK(C), .D(D), .Q(T0), .Q31(T1));
+      SRLC32E #(.INIT(INIT_R[64-1:32]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_1 (.A(A[4:0]), .CE(CE), .CLK(C), .D(T1), .Q(T2), .Q31(T3));
+      \$__SHREG_ #(.DEPTH(DEPTH-64), .INIT(INIT[DEPTH-64-1:0]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_2 (.C(C), .D(T3), .E(E), .Q(T4));
       MUXF7 fpga_mux_0 (.O(T5), .I0(T0), .I1(T2), .S(A[5]));
       MUXF7 fpga_mux_1 (.O(T6), .I0(T4), .I1(1'b0 /* unused */), .S(A[5]));
       MUXF8 fpga_mux_2 (.O(Q), .I0(T5), .I1(T6), .S(A[6]));
@@ -60,10 +76,10 @@ module \$__SHREG_ (input C, input D, input E, output Q);
     if (DEPTH > 97 && DEPTH <= 128) begin
       localparam [6:0] A = DEPTH-1;
       wire T0, T1, T2, T3, T4, T5, T6, T7, T8;
-      SRLC32E #(.INIT(INIT[32-1:0]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_0 (.A(A[4:0]), .CE(CE), .CLK(C), .D(D), .Q(T0), .Q31(T1));
-      SRLC32E #(.INIT(INIT[64-1:32]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_1 (.A(A[4:0]), .CE(CE), .CLK(C), .D(T1), .Q(T2), .Q31(T3));
-      SRLC32E #(.INIT(INIT[96-1:64]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_2 (.A(A[4:0]), .CE(CE), .CLK(C), .D(T3), .Q(T4), .Q31(T5));
-      \$__SHREG_ #(.DEPTH(DEPTH-96), .INIT(INIT[DEPTH-1:96]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_3 (.C(C), .D(T5), .E(E), .Q(T6));
+      SRLC32E #(.INIT(INIT_R[32-1:0]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_0 (.A(A[4:0]), .CE(CE), .CLK(C), .D(D), .Q(T0), .Q31(T1));
+      SRLC32E #(.INIT(INIT_R[64-1:32]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_1 (.A(A[4:0]), .CE(CE), .CLK(C), .D(T1), .Q(T2), .Q31(T3));
+      SRLC32E #(.INIT(INIT_R[96-1:64]), .IS_CLK_INVERTED(~CLKPOL[0])) fpga_srl_2 (.A(A[4:0]), .CE(CE), .CLK(C), .D(T3), .Q(T4), .Q31(T5));
+      \$__SHREG_ #(.DEPTH(DEPTH-96), .INIT(INIT[DEPTH-96-1:0]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_3 (.C(C), .D(T5), .E(E), .Q(T6));
       MUXF7 fpga_mux_0 (.O(T7), .I0(T0), .I1(T2), .S(A[5]));
       MUXF7 fpga_mux_1 (.O(T8), .I0(T4), .I1(T6), .S(A[5]));
       MUXF8 fpga_mux_2 (.O(Q), .I0(T7), .I1(T8), .S(A[6]));
@@ -72,16 +88,16 @@ module \$__SHREG_ (input C, input D, input E, output Q);
       // Handle cases where depth is just 1 over a convenient value,
       // in which case use the flop
       wire T0;
-      \$__SHREG_ #(.DEPTH(DEPTH-1), .INIT(INIT[DEPTH-2:0]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_0 (.C(C), .D(D), .E(E), .Q(T0));
-      \$__SHREG_ #(.DEPTH(1), .INIT(INIT[DEPTH-1]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_1 (.C(C), .D(T0), .E(E), .Q(Q));
+      \$__SHREG_ #(.DEPTH(DEPTH-1), .INIT(INIT[DEPTH-1:1]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_0 (.C(C), .D(D), .E(E), .Q(T0));
+      \$__SHREG_ #(.DEPTH(1), .INIT(INIT[0]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_1 (.C(C), .D(T0), .E(E), .Q(Q));
     end else
     begin
       // UG474 (v1.8, p34) states that:
       //   "There are no direct connections between slices to form longer shift
       //    registers, nor is the MC31 output at LUT B/C/D available."
       wire T0;
-      \$__SHREG_ #(.DEPTH(128), .INIT(INIT[128-1:0]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_0 (.C(C), .D(D), .E(E), .Q(T0));
-      \$__SHREG_ #(.DEPTH(DEPTH-128), .INIT(INIT[DEPTH-1:128]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_1 (.C(C), .D(T0), .E(E), .Q(Q));
+      \$__SHREG_ #(.DEPTH(128), .INIT(INIT[DEPTH-1:DEPTH-128]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_0 (.C(C), .D(D), .E(E), .Q(T0));
+      \$__SHREG_ #(.DEPTH(DEPTH-128), .INIT(INIT[DEPTH-128-1:0]), .CLKPOL(CLKPOL), .ENPOL(ENPOL)) fpga_srl_1 (.C(C), .D(T0), .E(E), .Q(Q));
     end
   endgenerate
 endmodule