EXT.v

/*
    This module implements the immediate number of expansion unit
*/
`include "ctrl_encode_def.v"
module EXT( 

	input 	[4:0] 			iimm_shamt,
    input	[11:0]			iimm,
	input	[11:0]			simm,
	input	[11:0]			bimm,
	input	[19:0]			uimm,
	input	[19:0]			jimm,
	input	[5:0]			EXTOp,

	output	reg [31:0] 	       immout
	);
   
always  @(*)
	case (EXTOp)
		`EXT_CTRL_ITYPE_SHAMT:   immout<={27'b0,iimm_shamt[4:0]};
		`EXT_CTRL_ITYPE:	immout <= {{32-12{iimm[11]}}, iimm[11:0]};
		`EXT_CTRL_STYPE:	immout <= {{32-12{simm[11]}}, simm[11:0]};
		`EXT_CTRL_BTYPE:        immout <= {{32-13{bimm[11]}}, bimm[11:0], 1'b0};
		`EXT_CTRL_UTYPE:	immout <= {uimm[19:0], 12'b0}; //???????????12??0
		`EXT_CTRL_JTYPE:	immout <= {{32-21{jimm[19]}}, jimm[19:0], 1'b0};
		default:	        immout <= 32'b0;
	endcase

       
endmodule