alu pre-shift

-changed ALU pre shift logic to use a 2 bit shifter instead of mux
2023-03-04 23:07:06 -08:00 · 2023-03-04 23:07:06 -08:00 · 4b1ee5a196
commit 4b1ee5a196
parent b0f152de28
1 changed files with 2 additions and 8 deletions
--- a/src/ieu/alu.sv
+++ b/src/ieu/alu.sv
@ -94,14 +94,8 @@ module alu #(parameter WIDTH=32) (
  end else assign rotA = A;
    
  if (`ZBA_SUPPORTED) begin: zbamuxes
-    // Pre-Shift Mux
-    always_comb
-      case (Funct3[2:1] & {2{PreShift}})
-        2'b00: CondShiftA = shA[WIDTH-1:0];
-        2'b01: CondShiftA = {shA[WIDTH-2:0],{1'b0}};   // sh1add
-        2'b10: CondShiftA = {shA[WIDTH-3:0],{2'b00}};  // sh2add
-        2'b11: CondShiftA = {shA[WIDTH-4:0],{3'b000}}; // sh3add
-      endcase
+    // Pre-Shift
+    assign CondShiftA = shA[WIDTH-1:0] << (Funct3[2:1] & {2{PreShift}});
  end else assign CondShiftA = A;

  // Addition