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[/] [openrisc/] [trunk/] [or1200/] [rtl/] [verilog/] [or1200_except.v] - Rev 609
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////////////////////////////////////////////////////////////////////// //// //// //// OR1200's Exception logic //// //// //// //// This file is part of the OpenRISC 1200 project //// //// http://www.opencores.org/project,or1k //// //// //// //// Description //// //// Handles all OR1K exceptions inside CPU block. //// //// //// //// To Do: //// //// - make it smaller and faster //// //// //// //// Author(s): //// //// - Damjan Lampret, lampret@opencores.org //// //// //// ////////////////////////////////////////////////////////////////////// //// //// //// Copyright (C) 2000 Authors and OPENCORES.ORG //// //// //// //// This source file may be used and distributed without //// //// restriction provided that this copyright statement is not //// //// removed from the file and that any derivative work contains //// //// the original copyright notice and the associated disclaimer. //// //// //// //// This source file is free software; you can redistribute it //// //// and/or modify it under the terms of the GNU Lesser General //// //// Public License as published by the Free Software Foundation; //// //// either version 2.1 of the License, or (at your option) any //// //// later version. //// //// //// //// This source is distributed in the hope that it will be //// //// useful, but WITHOUT ANY WARRANTY; without even the implied //// //// warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR //// //// PURPOSE. See the GNU Lesser General Public License for more //// //// details. //// //// //// //// You should have received a copy of the GNU Lesser General //// //// Public License along with this source; if not, download it //// //// from http://www.opencores.org/lgpl.shtml //// //// //// ////////////////////////////////////////////////////////////////////// // // $Log: or1200_except.v,v $ // // Revision 2.0 2010/06/30 11:00:00 ORSoC // Major update: // Structure reordered and bugs fixed. // synopsys translate_off `include "timescale.v" // synopsys translate_on `include "or1200_defines.v" `define OR1200_EXCEPTFSM_WIDTH 3 `define OR1200_EXCEPTFSM_IDLE `OR1200_EXCEPTFSM_WIDTH'd0 `define OR1200_EXCEPTFSM_FLU1 `OR1200_EXCEPTFSM_WIDTH'd1 `define OR1200_EXCEPTFSM_FLU2 `OR1200_EXCEPTFSM_WIDTH'd2 `define OR1200_EXCEPTFSM_FLU3 `OR1200_EXCEPTFSM_WIDTH'd3 `define OR1200_EXCEPTFSM_FLU4 `OR1200_EXCEPTFSM_WIDTH'd4 `define OR1200_EXCEPTFSM_FLU5 `OR1200_EXCEPTFSM_WIDTH'd5 // // Exception recognition and sequencing // module or1200_except ( // Clock and reset clk, rst, // Internal i/f sig_ibuserr, sig_dbuserr, sig_illegal, sig_align, sig_range, sig_dtlbmiss, sig_dmmufault, sig_int, sig_syscall, sig_trap, sig_itlbmiss, sig_immufault, sig_tick, ex_branch_taken, genpc_freeze, id_freeze, ex_freeze, wb_freeze, if_stall, if_pc, id_pc, ex_pc, wb_pc, id_flushpipe, ex_flushpipe, extend_flush, except_flushpipe, except_type, except_start, except_started, except_stop, except_trig, ex_void, abort_mvspr, branch_op, spr_dat_ppc, spr_dat_npc, datain, du_dsr, epcr_we, eear_we, esr_we, pc_we, epcr, eear, du_dmr1, du_hwbkpt, du_hwbkpt_ls_r, esr, sr_we, to_sr, sr, lsu_addr, abort_ex, icpu_ack_i, icpu_err_i, dcpu_ack_i, dcpu_err_i, sig_fp, fpcsr_fpee ); // // I/O // input clk; input rst; input sig_ibuserr; input sig_dbuserr; input sig_illegal; input sig_align; input sig_range; input sig_dtlbmiss; input sig_dmmufault; input sig_int; input sig_syscall; input sig_trap; input sig_itlbmiss; input sig_immufault; input sig_tick; input sig_fp; input fpcsr_fpee; input ex_branch_taken; input genpc_freeze; input id_freeze; input ex_freeze; input wb_freeze; input if_stall; input [31:0] if_pc; output [31:0] id_pc; output [31:0] ex_pc; output [31:0] wb_pc; input [31:0] datain; input [`OR1200_DU_DSR_WIDTH-1:0] du_dsr; input [24:0] du_dmr1; input du_hwbkpt; input du_hwbkpt_ls_r; input epcr_we; input eear_we; input esr_we; input pc_we; output [31:0] epcr; output [31:0] eear; output [`OR1200_SR_WIDTH-1:0] esr; input [`OR1200_SR_WIDTH-1:0] to_sr; input sr_we; input [`OR1200_SR_WIDTH-1:0] sr; input [31:0] lsu_addr; input id_flushpipe; input ex_flushpipe; output except_flushpipe; output extend_flush; output [`OR1200_EXCEPT_WIDTH-1:0] except_type; output except_start; output except_started; output [13:0] except_stop; output [13:0] except_trig; input ex_void; input [`OR1200_BRANCHOP_WIDTH-1:0] branch_op; output [31:0] spr_dat_ppc; output [31:0] spr_dat_npc; output abort_ex; output abort_mvspr; input icpu_ack_i; input icpu_err_i; input dcpu_ack_i; input dcpu_err_i; // // Internal regs and wires // reg [`OR1200_EXCEPT_WIDTH-1:0] except_type /* verilator public */; reg [31:0] id_pc /* verilator public */; reg id_pc_val; reg [31:0] ex_pc /* verilator public */; reg ex_pc_val; reg [31:0] wb_pc /* verilator public */; reg [31:0] dl_pc; reg [31:0] epcr; reg [31:0] eear; reg [`OR1200_SR_WIDTH-1:0] esr; reg [2:0] id_exceptflags; reg [2:0] ex_exceptflags; reg [`OR1200_EXCEPTFSM_WIDTH-1:0] state; reg extend_flush; reg extend_flush_last; reg ex_dslot /* verilator public */; reg delayed1_ex_dslot; reg delayed2_ex_dslot; wire except_started; wire except_flushpipe /* verilator public */; reg [2:0] delayed_iee; reg [2:0] delayed_tee; wire int_pending; wire tick_pending; wire fp_pending; reg trace_trap ; reg ex_freeze_prev; reg sr_ted_prev; reg dsr_te_prev; reg dmr1_st_prev ; reg dmr1_bt_prev ; wire dsr_te = ex_freeze_prev ? dsr_te_prev : du_dsr[`OR1200_DU_DSR_TE]; wire sr_ted = ex_freeze_prev ? sr_ted_prev : sr[`OR1200_SR_TED]; wire dmr1_st = ex_freeze_prev ? dmr1_st_prev: du_dmr1[`OR1200_DU_DMR1_ST] ; wire dmr1_bt = ex_freeze_prev ? dmr1_bt_prev: du_dmr1[`OR1200_DU_DMR1_BT] ; // // Simple combinatorial logic // assign except_started = extend_flush & except_start; assign except_start = (except_type != `OR1200_EXCEPT_NONE) & extend_flush; assign int_pending = sig_int & (sr[`OR1200_SR_IEE] | (sr_we & to_sr[`OR1200_SR_IEE])) & id_pc_val & delayed_iee[2] & ~ex_freeze & ~ex_branch_taken & ~ex_dslot & ~(sr_we & ~to_sr[`OR1200_SR_IEE]); assign tick_pending = sig_tick & (sr[`OR1200_SR_TEE] | (sr_we & to_sr[`OR1200_SR_TEE])) & id_pc_val & delayed_tee[2] & ~ex_freeze & ~ex_branch_taken & ~ex_dslot & ~(sr_we & ~to_sr[`OR1200_SR_TEE]); assign fp_pending = sig_fp & fpcsr_fpee & ~ex_freeze & ~ex_branch_taken & ~ex_dslot; // Abort write into RF by load & other instructions assign abort_ex = sig_dbuserr | sig_dmmufault | sig_dtlbmiss | sig_align | sig_illegal | ((du_hwbkpt | trace_trap) & ex_pc_val & !sr_ted & !dsr_te); // abort spr read/writes assign abort_mvspr = sig_illegal | ((du_hwbkpt | trace_trap) & ex_pc_val & !sr_ted & !dsr_te) ; assign spr_dat_ppc = wb_pc; assign spr_dat_npc = ex_void ? id_pc : ex_pc; // // Order defines exception detection priority // assign except_trig = { ex_exceptflags[1] & ~du_dsr[`OR1200_DU_DSR_IME], ex_exceptflags[0] & ~du_dsr[`OR1200_DU_DSR_IPFE], ex_exceptflags[2] & ~du_dsr[`OR1200_DU_DSR_BUSEE], sig_illegal & ~du_dsr[`OR1200_DU_DSR_IIE], sig_align & ~du_dsr[`OR1200_DU_DSR_AE], sig_dtlbmiss & ~du_dsr[`OR1200_DU_DSR_DME], sig_trap & ~du_dsr[`OR1200_DU_DSR_TE], sig_syscall & ~du_dsr[`OR1200_DU_DSR_SCE] & ~ex_freeze, sig_dmmufault & ~du_dsr[`OR1200_DU_DSR_DPFE], sig_dbuserr & ~du_dsr[`OR1200_DU_DSR_BUSEE], sig_range & ~du_dsr[`OR1200_DU_DSR_RE], fp_pending & ~du_dsr[`OR1200_DU_DSR_FPE], int_pending & ~du_dsr[`OR1200_DU_DSR_IE], tick_pending & ~du_dsr[`OR1200_DU_DSR_TTE] }; wire trace_cond = !ex_freeze && !ex_void && (1'b0 `ifdef OR1200_DU_DMR1_ST || dmr1_st `endif `ifdef OR1200_DU_DMR1_BT || ((branch_op != `OR1200_BRANCHOP_NOP) && (branch_op != `OR1200_BRANCHOP_RFE) && dmr1_bt) `endif ); assign except_stop = { tick_pending & du_dsr[`OR1200_DU_DSR_TTE], int_pending & du_dsr[`OR1200_DU_DSR_IE], ex_exceptflags[1] & du_dsr[`OR1200_DU_DSR_IME], ex_exceptflags[0] & du_dsr[`OR1200_DU_DSR_IPFE], ex_exceptflags[2] & du_dsr[`OR1200_DU_DSR_BUSEE], sig_illegal & du_dsr[`OR1200_DU_DSR_IIE], sig_align & du_dsr[`OR1200_DU_DSR_AE], sig_dtlbmiss & du_dsr[`OR1200_DU_DSR_DME], sig_dmmufault & du_dsr[`OR1200_DU_DSR_DPFE], sig_dbuserr & du_dsr[`OR1200_DU_DSR_BUSEE], sig_range & du_dsr[`OR1200_DU_DSR_RE], sig_trap & du_dsr[`OR1200_DU_DSR_TE], fp_pending & du_dsr[`OR1200_DU_DSR_FPE], sig_syscall & du_dsr[`OR1200_DU_DSR_SCE] & ~ex_freeze }; always @(posedge clk or `OR1200_RST_EVENT rst) begin if (rst == `OR1200_RST_VALUE) begin trace_trap <= 1'b0 ; end else if (!(trace_trap && !ex_pc_val)) begin trace_trap <= trace_cond & !dsr_te & !sr_ted ; end end always @(posedge clk or `OR1200_RST_EVENT rst) begin if (rst == `OR1200_RST_VALUE) begin ex_freeze_prev <= 1'b0 ; sr_ted_prev <= 1'b0 ; dsr_te_prev <= 1'b0 ; dmr1_st_prev <= 1'b0 ; dmr1_bt_prev <= 1'b0 ; end else begin ex_freeze_prev <= ex_freeze ; if (!ex_freeze_prev || ex_void) begin sr_ted_prev <= sr [`OR1200_SR_TED ] ; dsr_te_prev <= du_dsr [`OR1200_DU_DSR_TE ] ; dmr1_st_prev <= du_dmr1[`OR1200_DU_DMR1_ST] ; dmr1_bt_prev <= du_dmr1[`OR1200_DU_DMR1_BT] ; end end end `ifdef verilator // Function to access wb_pc (for Verilator). Have to hide this from // simulator, since functions with no inputs are not allowed in IEEE // 1364-2001. function [31:0] get_wb_pc; // verilator public get_wb_pc = wb_pc; endfunction // get_wb_pc // Function to access id_pc (for Verilator). Have to hide this from // simulator, since functions with no inputs are not allowed in IEEE // 1364-2001. function [31:0] get_id_pc; // verilator public get_id_pc = id_pc; endfunction // get_id_pc // Function to access ex_pc (for Verilator). Have to hide this from // simulator, since functions with no inputs are not allowed in IEEE // 1364-2001. function [31:0] get_ex_pc; // verilator public get_ex_pc = ex_pc; endfunction // get_ex_pc // Function to access except_type[3:0] (for Verilator). Have to hide this from // simulator, since functions with no inputs are not allowed in IEEE // 1364-2001. function [3:0] get_except_type; // verilator public get_except_type = except_type; endfunction // get_except_type `endif // // PC and Exception flags pipelines // always @(posedge clk or `OR1200_RST_EVENT rst) begin if (rst == `OR1200_RST_VALUE) begin id_pc <= 32'd0; id_pc_val <= 1'b0 ; id_exceptflags <= 3'b000; end else if (id_flushpipe) begin id_pc_val <= 1'b0 ; id_exceptflags <= 3'b000; end else if (!id_freeze) begin id_pc <= if_pc; id_pc_val <= 1'b1 ; id_exceptflags <= { sig_ibuserr, sig_itlbmiss, sig_immufault }; end end // // delayed_iee // // SR[IEE] should not enable interrupts right away // when it is restored with l.rfe. Instead delayed_iee // together with SR[IEE] enables interrupts once // pipeline is again ready. // always @(`OR1200_RST_EVENT rst or posedge clk) if (rst == `OR1200_RST_VALUE) delayed_iee <= 3'b000; else if (!sr[`OR1200_SR_IEE]) delayed_iee <= 3'b000; else delayed_iee <= {delayed_iee[1:0], 1'b1}; // // delayed_tee // // SR[TEE] should not enable tick exceptions right away // when it is restored with l.rfe. Instead delayed_tee // together with SR[TEE] enables tick exceptions once // pipeline is again ready. // always @(`OR1200_RST_EVENT rst or posedge clk) if (rst == `OR1200_RST_VALUE) delayed_tee <= 3'b000; else if (!sr[`OR1200_SR_TEE]) delayed_tee <= 3'b000; else delayed_tee <= {delayed_tee[1:0], 1'b1}; // // PC and Exception flags pipelines // always @(posedge clk or `OR1200_RST_EVENT rst) begin if (rst == `OR1200_RST_VALUE) begin ex_dslot <= 1'b0; ex_pc <= 32'd0; ex_pc_val <= 1'b0 ; ex_exceptflags <= 3'b000; delayed1_ex_dslot <= 1'b0; delayed2_ex_dslot <= 1'b0; end else if (ex_flushpipe) begin ex_dslot <= 1'b0; ex_pc_val <= 1'b0 ; ex_exceptflags <= 3'b000; delayed1_ex_dslot <= 1'b0; delayed2_ex_dslot <= 1'b0; end else if (!ex_freeze & id_freeze) begin ex_dslot <= 1'b0; ex_pc <= id_pc; ex_pc_val <= id_pc_val ; ex_exceptflags <= 3'b000; delayed1_ex_dslot <= ex_dslot; delayed2_ex_dslot <= delayed1_ex_dslot; end else if (!ex_freeze) begin ex_dslot <= ex_branch_taken; ex_pc <= id_pc; ex_pc_val <= id_pc_val ; ex_exceptflags <= id_exceptflags; delayed1_ex_dslot <= ex_dslot; delayed2_ex_dslot <= delayed1_ex_dslot; end end // // PC and Exception flags pipelines // always @(posedge clk or `OR1200_RST_EVENT rst) begin if (rst == `OR1200_RST_VALUE) begin wb_pc <= 32'd0; dl_pc <= 32'd0; end else if (!wb_freeze) begin wb_pc <= ex_pc; dl_pc <= wb_pc; end end // // We have started execution of exception handler: // 1. Asserted for 3 clock cycles // 2. Don't execute any instruction that is still in pipeline and is not part of exception handler // assign except_flushpipe = |except_trig & ~|state; // // Exception FSM that sequences execution of exception handler // // except_type signals which exception handler we start fetching in: // 1. Asserted in next clock cycle after exception is recognized // always @(posedge clk or `OR1200_RST_EVENT rst) begin if (rst == `OR1200_RST_VALUE) begin state <= `OR1200_EXCEPTFSM_IDLE; except_type <= `OR1200_EXCEPT_NONE; extend_flush <= 1'b0; epcr <= 32'b0; eear <= 32'b0; esr <= {2'h1, {`OR1200_SR_WIDTH-3{1'b0}}, 1'b1}; extend_flush_last <= 1'b0; end else begin `ifdef OR1200_CASE_DEFAULT case (state) // synopsys parallel_case `else case (state) // synopsys full_case parallel_case `endif `OR1200_EXCEPTFSM_IDLE: if (except_flushpipe) begin state <= `OR1200_EXCEPTFSM_FLU1; extend_flush <= 1'b1; esr <= sr_we ? to_sr : sr; casez (except_trig) `ifdef OR1200_EXCEPT_ITLBMISS 14'b1?_????_????_????: begin except_type <= `OR1200_EXCEPT_ITLBMISS; eear <= ex_dslot ? ex_pc : ex_pc; epcr <= ex_dslot ? wb_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_IPF 14'b01_????_????_????: begin except_type <= `OR1200_EXCEPT_IPF; eear <= ex_dslot ? ex_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc; epcr <= ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc; end `endif `ifdef OR1200_EXCEPT_BUSERR 14'b00_1???_????_????: begin // Insn. Bus Error except_type <= `OR1200_EXCEPT_BUSERR; eear <= ex_dslot ? wb_pc : ex_pc; epcr <= ex_dslot ? wb_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_ILLEGAL 14'b00_01??_????_????: begin except_type <= `OR1200_EXCEPT_ILLEGAL; eear <= ex_pc; epcr <= ex_dslot ? wb_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_ALIGN 14'b00_001?_????_????: begin except_type <= `OR1200_EXCEPT_ALIGN; eear <= lsu_addr; epcr <= ex_dslot ? wb_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_DTLBMISS 14'b00_0001_????_????: begin except_type <= `OR1200_EXCEPT_DTLBMISS; eear <= lsu_addr; epcr <= ex_dslot ? wb_pc : delayed1_ex_dslot ? dl_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_TRAP 14'b00_0000_1???_????: begin except_type <= `OR1200_EXCEPT_TRAP; epcr <= ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_SYSCALL 14'b00_0000_01??_????: begin except_type <= `OR1200_EXCEPT_SYSCALL; epcr <= ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc; end `endif `ifdef OR1200_EXCEPT_DPF 14'b00_0000_001?_????: begin except_type <= `OR1200_EXCEPT_DPF; eear <= lsu_addr; epcr <= ex_dslot ? wb_pc : delayed1_ex_dslot ? dl_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_BUSERR 14'b00_0000_0001_????: begin // Data Bus Error except_type <= `OR1200_EXCEPT_BUSERR; eear <= lsu_addr; epcr <= ex_dslot ? wb_pc : delayed1_ex_dslot ? dl_pc : ex_pc; end `endif `ifdef OR1200_EXCEPT_RANGE 14'b00_0000_0000_1???: begin except_type <= `OR1200_EXCEPT_RANGE; epcr <= ex_dslot ? wb_pc : delayed1_ex_dslot ? id_pc : delayed2_ex_dslot ? id_pc : id_pc; end `endif `ifdef OR1200_EXCEPT_FLOAT 14'b00_0000_0000_01??: begin except_type <= `OR1200_EXCEPT_FLOAT; epcr <= id_pc; end `endif `ifdef OR1200_EXCEPT_INT 14'b00_0000_0000_001?: begin except_type <= `OR1200_EXCEPT_INT; epcr <= id_pc; end `endif `ifdef OR1200_EXCEPT_TICK 14'b00_0000_0000_0001: begin except_type <= `OR1200_EXCEPT_TICK; epcr <= id_pc; end `endif default: except_type <= `OR1200_EXCEPT_NONE; endcase end else if (pc_we) begin state <= `OR1200_EXCEPTFSM_FLU1; extend_flush <= 1'b1; end else begin if (epcr_we) epcr <= datain; if (eear_we) eear <= datain; if (esr_we) esr <= {datain[`OR1200_SR_WIDTH-1], 1'b1, datain[`OR1200_SR_WIDTH-3:0]}; end `OR1200_EXCEPTFSM_FLU1: if (icpu_ack_i | icpu_err_i | genpc_freeze) state <= `OR1200_EXCEPTFSM_FLU2; `OR1200_EXCEPTFSM_FLU2: `ifdef OR1200_EXCEPT_TRAP if (except_type == `OR1200_EXCEPT_TRAP) begin state <= `OR1200_EXCEPTFSM_IDLE; extend_flush <= 1'b0; extend_flush_last <= 1'b0; except_type <= `OR1200_EXCEPT_NONE; end else `endif state <= `OR1200_EXCEPTFSM_FLU3; `OR1200_EXCEPTFSM_FLU3: begin state <= `OR1200_EXCEPTFSM_FLU4; end `OR1200_EXCEPTFSM_FLU4: begin state <= `OR1200_EXCEPTFSM_FLU5; extend_flush <= 1'b0; extend_flush_last <= 1'b0; // damjan end `ifdef OR1200_CASE_DEFAULT default: begin `else `OR1200_EXCEPTFSM_FLU5: begin `endif if (!if_stall && !id_freeze) begin state <= `OR1200_EXCEPTFSM_IDLE; except_type <= `OR1200_EXCEPT_NONE; extend_flush_last <= 1'b0; end end endcase end end endmodule
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