feat: add scalar fexp support

hw/rtl/fpu/VX_fpu_exp.sv

@@ -0,0 +1,92 @@
+// Copyright © 2019-2023
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+`include "VX_fpu_define.vh"
+`ifdef SV_DPI
+`include "float_dpi.vh"
+`else
+`ERROR(("VX_fpu_exp requires SV_DPI; replace dpi_fexp with synthesizable exp RTL for synthesis"))
+`endif
+
+module VX_fpu_exp import VX_fpu_pkg::*; #(
+    parameter NUM_LANES = 1,
+    parameter TAGW = 1
+) (
+    input wire clk,
+    input wire reset,
+
+    output wire ready_in,
+    input wire  valid_in,
+
+    input wire [NUM_LANES-1:0] lane_mask,
+
+    input wire [TAGW-1:0] tag_in,
+
+    input wire [NUM_LANES-1:0][31:0] dataa,
+    output wire [NUM_LANES-1:0][31:0] result,
+
+    output wire has_fflags,
+    output wire [`FP_FLAGS_BITS-1:0] fflags,
+
+    output wire [TAGW-1:0] tag_out,
+
+    input wire  ready_out,
+    output wire valid_out
+);
+    wire stall  = ~ready_out && valid_out;
+    wire enable = ~stall;
+
+    fflags_t [NUM_LANES-1:0] per_lane_fflags;
+    wire [NUM_LANES-1:0] lane_mask_out;
+
+    VX_shift_register #(
+        .DATAW  (1 + NUM_LANES + TAGW),
+        .DEPTH  (`LATENCY_FEXP),
+        .RESETW (1)
+    ) shift_reg (
+        .clk      (clk),
+        .reset    (reset),
+        .enable   (enable),
+        .data_in  ({valid_in, lane_mask, tag_in}),
+        .data_out ({valid_out, lane_mask_out, tag_out})
+    );
+
+    assign ready_in = enable;
+
+    for (genvar i = 0; i < NUM_LANES; ++i) begin
+        reg [63:0] r;
+        `UNUSED_VAR (r)
+
+        fflags_t f;
+
+        always @(*) begin
+            dpi_fexp(enable && valid_in, int'(0), {32'hffffffff, dataa[i]}, r, f);
+        end
+
+        VX_shift_register #(
+            .DATAW  (32 + $bits(fflags_t)),
+            .DEPTH  (`LATENCY_FEXP)
+        ) shift_req_dpi (
+            .clk      (clk),
+            `UNUSED_PIN (reset),
+            .enable   (enable),
+            .data_in  ({r[31:0], f}),
+            .data_out ({result[i], per_lane_fflags[i]})
+        );
+    end
+
+    assign has_fflags = 1;
+
+    `FPU_MERGE_FFLAGS(fflags, per_lane_fflags, lane_mask_out, NUM_LANES);
+
+endmodule