cpu/src/exec_op/shift_op_b.vhd

   1 library IEEE;\r
   2 use IEEE.std_logic_1164.all;\r
   3 use IEEE.numeric_std.all;\r
   4 \r
   5 use work.common_pkg.all;\r
   6 use work.alu_pkg.all;\r
   7 \r
   8 architecture shift_op of exec_op is\r
   9 \r
  10         signal logic, ls, carry : std_logic;\r
  11 \r
  12 begin\r
  13 \r
  14         logic <=  op_detail(LOG_OPT);\r
  15         ls      <=  op_detail(LEFT_OPT);\r
  16         carry <= op_detail(CARRY_OPT);\r
  17 \r
  18 calc: process(left_operand, right_operand, logic,ls, carry, alu_state)\r
  19                 variable alu_result_v : alu_result_rec;\r
  20                 variable tmp_shift : bit_vector(gp_register_t'length+1 downto 0);\r
  21                 variable tmp_sb : std_logic;\r
  22         begin\r
  23                 alu_result_v := alu_state;\r
  24                 \r
  25                 if ls = '1' then\r
  26                         tmp_sb := (carry and alu_state.status.carry and logic);\r
  27                         tmp_shift :=  to_bitvector(alu_state.status.carry & left_operand & tmp_sb);\r
  28                         tmp_shift :=  tmp_shift sla to_integer(unsigned(right_operand)(SHIFT_WIDTH-1 downto 0));\r
  29                         \r
  30                         alu_result_v.status.carry := to_stdlogicvector(tmp_shift)(tmp_shift'high);\r
  31                         \r
  32                 else\r
  33                         tmp_sb := (carry and alu_state.status.carry and logic) or (not(logic) and left_operand(gp_register_t'high));\r
  34                         tmp_shift := to_bitvector(tmp_sb & left_operand & alu_state.status.carry);\r
  35                         tmp_shift := tmp_shift sra to_integer(unsigned(right_operand)(SHIFT_WIDTH-1 downto 0));\r
  36                         \r
  37                         alu_result_v.status.carry := to_stdlogicvector(tmp_shift)(0);\r
  38                 end if;\r
  39                 \r
  40                 alu_result_v.result := to_stdlogicvector(tmp_shift)(gp_register_t'length downto 1);\r
  41                 \r
  42                 alu_result <= alu_result_v;\r
  43                 \r
  44 end process;\r
  45 \r
  46 end architecture shift_op;\r