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// +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // This file is part of the M32632 project // http://opencores.org/project,m32632 // // Filename: CACHE_LOGIK.v // Version: 1.1 bug fix // History: 1.0 first release of 30 Mai 2015 // Date: 7 October 2015 // // Copyright (C) 2015 Udo Moeller // // 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 // // +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // Modules contained in this file: // 1. DEBUG_AE Debug unit for address compare in data cache // 2. MMU_UP MMU memory update and initalization controller // 3. DCA_CONTROL Data cache valid memory update and initalization controller // 4. MMU_MATCH MMU virtual address match detector // 5. CA_MATCH Cache tag match detector // 6. DCACHE_SM Data cache state machine // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // 1. DEBUG_AE Debug unit for address compare in data cache // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ module DEBUG_AE ( DBG_IN, READ, WRITE, USER, VIRTUELL, ACC_OK, VADR_R, MMU_Q, ENBYTE, DBG_HIT ); input [40:2] DBG_IN; input READ,WRITE; input USER; input VIRTUELL; input ACC_OK; input [31:2] VADR_R; input [19:0] MMU_Q; input [3:0] ENBYTE; output DBG_HIT; wire sd,ud,crd,cwr,vnp; wire make; wire virt_adr,real_adr,page_adr; wire byte_en; assign sd = DBG_IN[40]; assign ud = DBG_IN[39]; assign crd = DBG_IN[38]; assign cwr = DBG_IN[37]; assign vnp = DBG_IN[36]; assign make = ((ud & USER) | (sd & ~USER)) // compare USER or SUPERVISOR & (VIRTUELL == vnp) // compare real or virtual address & ((cwr & WRITE) | (crd & READ)); // compare READ or WRITE assign virt_adr = (MMU_Q == DBG_IN[31:12]); assign real_adr = (VADR_R[31:12] == DBG_IN[31:12]); assign page_adr = (VADR_R[11:2] == DBG_IN[11:2]); assign byte_en = |(ENBYTE & DBG_IN[35:32]); assign DBG_HIT = ACC_OK // all valid & make // selection is valid & (VIRTUELL ? virt_adr : real_adr) & page_adr // address & byte_en; // Byte Enable endmodule // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // 2. MMU_UP MMU memory update and initalization controller // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ module MMU_UP ( BCLK, BRESET, NEW_PTB, PTB1, IVAR, WR_MRAM, VADR, VADR_R, MVALID, UPDATE, WE_MV, WADR_MV, RADR_MV, DAT_MV, NEW_PTB_RUN ); input BCLK; input BRESET; input NEW_PTB; // the MMU memory is cleared. Pulse of one BCLK cycle, Op-Dec is waiting input PTB1; // which one input IVAR; input WR_MRAM; // BCLK : update MRAM and MMU_VAL input [19:16] VADR,VADR_R; // For update input [31:0] MVALID,UPDATE; output WE_MV; // Write Enable MMU Valid output [3:0] WADR_MV,RADR_MV; output [31:0] DAT_MV; output NEW_PTB_RUN; reg neue_ptb,wr_flag,old_rst,run_over; reg [3:0] count; wire [15:0] new_val; assign WE_MV = wr_flag | WR_MRAM | IVAR; // write on falling edge BCLK assign RADR_MV = run_over ? count : VADR; assign WADR_MV = wr_flag ? (count - 4'b0001) : VADR_R; assign DAT_MV = wr_flag ? {MVALID[31:16],new_val} : UPDATE; // Only the matching entries are cleared : PTB0/PTB1 // [31:16] Address-Space memory, [15:0] Valid memory assign new_val = neue_ptb ? (PTB1 ? (MVALID[15:0] & ~MVALID[31:16]) : (MVALID[15:0] & MVALID[31:16])) : 16'h0; always @(posedge BCLK or negedge BRESET) if (!BRESET) neue_ptb <= 1'b0; else neue_ptb <= NEW_PTB | (neue_ptb & run_over); always @(posedge BCLK) old_rst <= BRESET; // after Reset all will be set to 0 always @(posedge BCLK) run_over <= ((~old_rst | NEW_PTB) | (run_over & (count != 4'hF))) & BRESET; always @(posedge BCLK) count <= run_over ? count + 4'h1 : 4'h0; always @(posedge BCLK) wr_flag <= run_over; assign NEW_PTB_RUN = wr_flag; // Info to Op-Dec endmodule // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // 3. DCA_CONTROL Data cache valid memory update and initalization controller // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ module DCA_CONTROL ( BCLK, MCLK, BRESET, CUPDATE, DRAM_ACC, CA_SET, HIT_ALL, WRCFG, VADR_R, UPDATE, INVAL_A, WRITE, WCTRL, KILL, WRCRAM0, WRCRAM1, WE_CV, WADR_CV, DAT_CV, INIT_CA_RUN, WRSET0, WRSET1 ); input BCLK; input MCLK; input BRESET; input CUPDATE; // State CUPDATE : Cache is filled from DRAM input DRAM_ACC; input CA_SET; input HIT_ALL; // a complete cache hit ! input WRCFG; // static signal : GND or VDD input [11:7] VADR_R; input [23:0] UPDATE; input INVAL_A; input WRITE; input [1:0] WCTRL; // [1] : Read Burst Signal from DRAM controller, MCLK aligned. [0] : Cache inhibit input KILL; // valid Ram must be updated because of collision ... or CINV output WRCRAM0,WRCRAM1; output WE_CV; output [4:0] WADR_CV; output [23:0] DAT_CV; output INIT_CA_RUN; output WRSET0,WRSET1; reg [1:0] state; reg [4:0] acount; reg ca_set_d; reg dly_bclk,zero,wr_puls; reg [2:0] count,refer; wire countf; // physical address is stored in TAG-RAM assign WRCRAM0 = (CUPDATE & ~WCTRL[0]) & ~CA_SET; assign WRCRAM1 = (CUPDATE & ~WCTRL[0]) & CA_SET; // Load Valid RAM : assign WE_CV = state[1] | HIT_ALL | (CUPDATE & ~WCTRL[0]) | KILL; // Hit All for "Last" Update assign WADR_CV = state[1] ? acount : VADR_R; assign DAT_CV = state[1] ? 24'h0 : UPDATE; // Clear of Cache-Valid RAMs : 32 clocks of BCLK assign countf = (acount == 5'h1F); always @(posedge BCLK) casex ({BRESET,INVAL_A,countf,state[1:0]}) 5'b0xx_xx : state <= 2'b01; 5'b1xx_01 : state <= 2'b10; // start counter 5'b10x_00 : state <= 2'b00; // wait ... 5'b11x_00 : state <= 2'b10; 5'b1x0_10 : state <= 2'b10; 5'b1x1_10 : state <= 2'b00; default : state <= 2'b0; endcase always @(posedge BCLK) if (!state[1]) acount <= 5'h0; else acount <= acount + 5'h01; assign INIT_CA_RUN = state[1]; always @(posedge BCLK) if (DRAM_ACC) ca_set_d <= CA_SET; // WRITE Control in data RAMs assign WRSET0 = ( ~CA_SET & WRITE & HIT_ALL & wr_puls) | (WCTRL[1] & ~ca_set_d); assign WRSET1 = ( CA_SET & WRITE & HIT_ALL & wr_puls) | (WCTRL[1] & ca_set_d); // ++++++++++++ Special circuit for Timing of write pulse for data RAM of data cache +++++++++ always @(negedge MCLK) dly_bclk <= BCLK; always @(negedge MCLK) zero <= BCLK & ~dly_bclk; always @(posedge MCLK) if (zero) count <= 3'd0; else count <= count + 3'd1; // count at zero , ref Wert // 1 : --- always on 5 : 100 001 // 2 : 001 000 6 : 101 010 // 3 : 010 010 7 : 110 011 // 4 : 011 000 8 : 111 100 always @(posedge MCLK) if (zero) refer <= {(count == 3'd7),((count == 3'd5) | (count[1:0] == 2'b10)),(count[2] & ~count[0])}; always @(posedge MCLK) wr_puls <= (count == refer) | WRCFG; endmodule // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // 4. MMU_MATCH MMU virtual address match detector // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ module MMU_MATCH ( USER, READ, WRITE, RMW, MCR_FLAGS, MVALID, VADR_R, MMU_VA, IVAR, VIRTUELL, MMU_HIT , UPDATE, PROT_ERROR, CI, SEL_PTB1 ); input USER; input READ; input WRITE; input RMW; input [2:0] MCR_FLAGS; input [31:0] MVALID; input [31:12] VADR_R; input [31:16] MMU_VA; input [1:0] IVAR; // Invalidate Entry output VIRTUELL; // only for Adress-Mux output MMU_HIT; output [31:0] UPDATE; output reg PROT_ERROR; // if valid must suppress write in Write Buffer and cache output CI,SEL_PTB1; reg [15:0] maske; wire adr_space,as_sorte,match,alles_ok; wire [15:0] val_bits,as_bits; wire ena_prot; wire zugriff; assign zugriff = READ | WRITE; always @(VADR_R) case (VADR_R[15:12]) 4'h0 : maske = 16'h0001; 4'h1 : maske = 16'h0002; 4'h2 : maske = 16'h0004; 4'h3 : maske = 16'h0008; 4'h4 : maske = 16'h0010; 4'h5 : maske = 16'h0020; 4'h6 : maske = 16'h0040; 4'h7 : maske = 16'h0080; 4'h8 : maske = 16'h0100; 4'h9 : maske = 16'h0200; 4'hA : maske = 16'h0400; 4'hB : maske = 16'h0800; 4'hC : maske = 16'h1000; 4'hD : maske = 16'h2000; 4'hE : maske = 16'h4000; 4'hF : maske = 16'h8000; endcase assign VIRTUELL = USER ? MCR_FLAGS[0] : MCR_FLAGS[1]; assign adr_space = IVAR[1] ? IVAR[0] : (MCR_FLAGS[2] & USER); // adr_space = IVARx ? 1 or 0 : DualSpace & TU assign as_sorte = ((MVALID[31:16] & maske) != 16'h0); assign match = (VADR_R[31:20] == MMU_VA[31:20]) & (adr_space == as_sorte) & ((MVALID[15:0] & maske) != 16'h0000); assign alles_ok = match & ( ~WRITE | MMU_VA[17] ) & ~PROT_ERROR; // Modified - Flag : reload the PTE // if MMU_HIT = 0 then there is no Write-Buffer access abd no update of cache ! assign MMU_HIT = zugriff ? ( VIRTUELL ? alles_ok : 1'b1 ) : 1'b0 ; // MMU off : then always HIT assign val_bits = IVAR[1] ? (MVALID[15:0] & (match ? ~maske : 16'hFFFF)) : (MVALID[15:0] | maske); assign as_bits = IVAR[1] ? MVALID[31:16] : (adr_space ? (MVALID[31:16] | maske) : (MVALID[31:16] & ~maske)); assign UPDATE = {as_bits,val_bits}; assign ena_prot = zugriff & VIRTUELL & match; // A Protection error must suppress write in WB and cache always @(ena_prot or MMU_VA or USER or WRITE or RMW) case ({ena_prot,MMU_VA[19:18]}) 3'b100 : PROT_ERROR = USER | WRITE | RMW; // Only Supervisor READ 3'b101 : PROT_ERROR = USER; // no USER access 3'b110 : PROT_ERROR = USER & (WRITE | RMW); // USER only READ default : PROT_ERROR = 1'b0; endcase assign CI = VIRTUELL & MMU_VA[16]; assign SEL_PTB1 = adr_space; // For PTE update endmodule // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // 5. CA_MATCH Cache tag match detector // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ module CA_MATCH ( CVALID, IOSEL, ADDR, TAG0, TAG1, CFG, WRITE, MMU_HIT, CI, INVAL_L, KDET, ENDRAM, DC_ILO, CA_HIT, CA_SET, UPDATE, IO_SPACE, USE_CA, WB_ACC, KILL ); input [23:0] CVALID; input [3:0] IOSEL; input [27:4] ADDR; input [27:12] TAG0,TAG1; input [1:0] CFG; // LDC , DC input WRITE; input MMU_HIT; input CI; input INVAL_L; // invalid cache line input KDET; input ENDRAM; input DC_ILO; // CBITI/SBITI special case output CA_HIT; output CA_SET; // if no Hit then says SET where to store output [23:0] UPDATE; // Update Information for CVALID memory output IO_SPACE; output USE_CA; output WB_ACC; output KILL; reg [7:0] maske; wire match_0,match_1; wire valid_0,valid_1; wire select; wire clear; wire [7:0] update_0,update_1,lastinfo; wire sel_dram; always @(ADDR) case (ADDR[6:4]) 3'h0 : maske = 8'h01; 3'h1 : maske = 8'h02; 3'h2 : maske = 8'h04; 3'h3 : maske = 8'h08; 3'h4 : maske = 8'h10; 3'h5 : maske = 8'h20; 3'h6 : maske = 8'h40; 3'h7 : maske = 8'h80; endcase assign valid_0 = (( CVALID[7:0] & maske) != 8'h00); assign valid_1 = ((CVALID[15:8] & maske) != 8'h00); assign match_0 = ( TAG0 == ADDR[27:12] ); // 4KB assign match_1 = ( TAG1 == ADDR[27:12] ); // 4KB assign CA_HIT = ((valid_0 & match_0) | (valid_1 & match_1)) & ~DC_ILO & CFG[0]; // which SET is written in cache miss ? If both are valid the last used is not taken assign select = (valid_1 & valid_0) ? ~((CVALID[23:16] & maske) != 8'h00) : valid_0; // Last-used field = CVALID[23:16] assign CA_SET = CA_HIT ? (valid_1 & match_1) : select; assign clear = INVAL_L | KDET; // INVAL_L is from CINV assign update_0 = CA_SET ? CVALID[7:0] : (clear ? (CVALID[7:0] & ~maske) : (CVALID[7:0] | maske)); assign update_1 = CA_SET ? (clear ? (CVALID[15:8] & ~maske) : (CVALID[15:8] | maske)) : CVALID[15:8]; assign lastinfo = CA_HIT ? (CA_SET ? (CVALID[23:16] | maske) : (CVALID[23:16] & ~maske)) : CVALID[23:16]; assign UPDATE = {lastinfo,update_1,update_0}; assign KILL = clear & CA_HIT & ~CFG[1]; // only if cache is not locked assign sel_dram = (IOSEL == 4'b0000) & ENDRAM; // at the moment the first 256 MB of memory assign IO_SPACE = ~sel_dram; // not DRAM or DRAM ist off assign USE_CA = ~CI & ~DC_ILO & CFG[0] & ~CFG[1]; // CI ? ILO ? Cache on ? Locked Cache ? assign WB_ACC = WRITE & MMU_HIT & sel_dram; endmodule // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ // // 6. DCACHE_SM Data cache state machine // // ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ module DCACHE_SM ( BCLK, BRESET, IO_SPACE, MDONE, IO_READY, MMU_HIT, CA_HIT, READ, WRITE, ZTEST, RMW, CAPDAT, VADR_R, IC_VA, USE_CA, PTB_WR, PTB_SEL, SEL_PTB1, CPU_OUT, USER, PROT_ERROR, WB_ACC, ENWR, ADR_EQU, IC_PREQ, FILLRAM, ICTODC, RWVAL, VIRTUELL, QWATWO, DRAM_ACC, DRAM_WR, IO_ACC, IO_RD, IO_WR, PTE_MUX, PD_MUX, PKEEP, PTE_ADR, PTE_DAT, HIT_ALL, ACC_OK, ABORT, PROTECT, IACC_STAT, ABO_LEVEL1, WR_MRAM, CUPDATE, AUX_DAT, NEW_PTB, PTB_ONE, MMU_DIN, IC_SIGS, KOMUX, KDET, DMA_MUX, HLDA, RWVFLAG, PTE_STAT ); input BCLK; input BRESET; input IO_SPACE; input MDONE; // Memory Done : feedback from DRAM Controller, BCLK aligned ! input IO_READY; input MMU_HIT,CA_HIT; input READ,WRITE,ZTEST,RMW; input [31:0] CAPDAT; input [31:12] VADR_R,IC_VA; input USE_CA; input PTB_WR,PTB_SEL; input SEL_PTB1; input [27:12] CPU_OUT; // used for PTB0/1 input USER; input PROT_ERROR; input WB_ACC; input ENWR; // Enable WRITE from DRAM input ADR_EQU; input IC_PREQ; input FILLRAM; input [3:0] ICTODC; // multiple signals from ICACHE, especially DMA input [1:0] RWVAL; // RDVAL+WRVAL Operation input VIRTUELL; // for RDVAL/WRVAL input QWATWO; output reg DRAM_ACC,DRAM_WR; output IO_ACC,IO_RD,IO_WR; output PTE_MUX,PD_MUX,PKEEP; output [27:0] PTE_ADR; output [19:0] PTE_DAT; output HIT_ALL; output ACC_OK; output ABORT,PROTECT; output [3:1] IACC_STAT; output ABO_LEVEL1; output WR_MRAM; output CUPDATE; output AUX_DAT; output reg NEW_PTB; output reg PTB_ONE; output [23:0] MMU_DIN; output [1:0] IC_SIGS; output KOMUX; output KDET; // Signal for detection of collision output DMA_MUX; output HLDA; // active low output RWVFLAG; // RDVAL/WRVAL result output [1:0] PTE_STAT; reg IO_WR,IO_RD; reg [1:0] pl_dat; reg [6:0] new_state; reg [2:0] cap_dat; // only for analyse of timing reg mem_done; reg rd_done; reg [2:0] pstate; reg pte_run_wr; reg [1:0] prot_level1; reg card_flag; reg [27:12] ptb0,ptb1; reg write_ok; reg icp_acc; reg pte_modi; reg [2:0] ko_state; reg dma_run; reg dma_kdet; reg rwv_bit; reg prot_i; reg rd_rdy; wire [27:12] ptb10; wire [31:12] virtual_adr; wire io_busy; wire dram_go; wire pte_sel; wire pte_acc; wire do_ca_rd,pte_go,do_ic_p; wire valid,valid_a,refer,modi; wire level1,level2; wire rd_level2; wire wr_req; wire wr_dram; wire wr_icmram; wire rd_ende; wire pte_dat_8; wire pte_wr_sig; wire run_dc; wire kostart; wire dma; wire dma_go; wire zugriff; wire mmu_hit_i; wire do_zt; wire zt_ok; wire [1:0] acc_level; wire user_ptw,wr_ptw; wire pte_puls; always @(posedge BCLK) cap_dat <= CAPDAT[2:0]; // if USER not virtual then ZTEST is quickly done assign zugriff = READ | WRITE | (ZTEST & VIRTUELL); assign mmu_hit_i = MMU_HIT & ~ZTEST; // WB_ACC is a successful WRITE access, ICTODC[0] is coherent Logik release : >=3 entries in FIFO assign wr_req = WB_ACC & ((ENWR & ICTODC[0]) | (DRAM_WR & ADR_EQU)); // release done by DRAM signal ENWR assign rd_ende = CA_HIT | rd_rdy; // CA_HIT only when Cache activ ! always @( zugriff // READ or WRITE or ZTEST , global control or PROT_ERROR // must not be // or IO_SPACE // access of IO world or io_busy // is access already running ? // or mmu_hit_i // Hit in MMU , now only a READ can happen or READ or wr_req or rd_ende // Cache Hit // or DRAM_ACC // DRAM Access : shows an active state or pte_acc // PTE access is running // or IC_PREQ // PTE Request from ICACHE // or dma // DMA Request or dma_run ) // DMA running // #_# #_# #_# #_# casex ({zugriff,PROT_ERROR,IO_SPACE,io_busy,mmu_hit_i,READ,wr_req,rd_ende,DRAM_ACC,pte_acc,IC_PREQ,dma,dma_run}) // MMU Miss : PTE load from memory , valid too if WRITE and M=0 13'b10_xx_0xxx_x0_x_x0 : new_state = 7'b0001010; // start PTE access // IO-Address selected : external access starts if not busy because of WRITE 13'b10_10_1xxx_x0_x_x0 : new_state = 7'b0000001; // DRAM access : Cache Miss at READ : 13'b10_0x_1100_00_x_x0 : new_state = 7'b0010010; // DRAM access : WRITE 13'b10_0x_101x_x0_x_x0 : new_state = 7'b0000100; // PTE Request ICACHE , IO access with WRITE is stored - parallel DRAM access possible 13'b0x_xx_xxxx_x0_1_00 : new_state = 7'b0101010; // no access 13'b10_0x_1101_x0_1_x0 : new_state = 7'b0101010; // if successful READ a PTE access can happen in parallel // DMA access. Attention : no IO-Write access in background and no ICACHE PTE access ! 13'b0x_x0_xxxx_xx_0_10 : new_state = 7'b1000000; // DMA access is started default : new_state = 7'b0; endcase assign IO_ACC = new_state[0]; // to load registers for data, addr und BE, signal one pulse assign dram_go = new_state[1] | rd_level2 ; assign wr_dram = new_state[2]; // pulse only assign pte_go = new_state[3]; assign do_ca_rd = new_state[4]; assign do_ic_p = new_state[5]; assign dma_go = new_state[6]; // ZTEST logic is for the special case when a write access is crossing page boundaries assign do_zt = ZTEST & ~icp_acc; // 0 is pass , 1 is blocked. RWVAL[0] is 1 if WRVAL. Level 1 can only be blocked, otherwise ABORT or Level 2 is following. always @(posedge BCLK) if (mem_done) rwv_bit <= level2 ? ~(cap_dat[2] & (~RWVAL[0] | cap_dat[1])) : 1'b1; assign RWVFLAG = VIRTUELL & rwv_bit; assign zt_ok = mem_done & (RWVAL[1] ? (~cap_dat[2] | (RWVAL[0] & ~cap_dat[1]) | level2) // Level 2 always ok : (cap_dat[0] & ~prot_i & level2) ); // "normal" access // PTE access logic, normal state machine // Updates to the PTEs are normal WRITE request to DRAM, therefore no MDONE at Write assign modi = ~CAPDAT[8] & WRITE & write_ok & ~icp_acc; // is "1" if the Modified Bit must be set assign refer = CAPDAT[7] | do_zt; // Assumption "R" Bit is set if RDVAL/WRVAL and page border test assign valid = (do_zt & RWVAL[1]) ? (cap_dat[2] & (cap_dat[1] | ~RWVAL[0]) & cap_dat[0] & level1) : (cap_dat[0] & ~prot_i); always @(posedge BCLK) mem_done <= MDONE & pte_acc; always @(posedge BCLK or negedge BRESET) if (!BRESET) pstate <= 3'h0; else casex ({pte_go,mem_done,valid,refer,modi,pte_run_wr,pstate}) 9'b0x_xxxx_000 : pstate <= 3'd0; // nothing to do 9'b1x_xxxx_000 : pstate <= 3'd4; // start 9'bx0_xxxx_100 : pstate <= 3'd4; // wait for Level 1 9'bx1_0xxx_100 : pstate <= 3'd0; // THAT'S ABORT ! 9'bx1_11xx_100 : pstate <= 3'd6; // PTE Level 1 was referenced , next is Level 2 9'bx1_10xx_100 : pstate <= 3'd5; // for writing of modified Level 1 : R=1 9'bxx_xxx0_101 : pstate <= 3'd5; // write must wait 9'bxx_xxx1_101 : pstate <= 3'd6; // one wait cycle 9'bx0_xxxx_110 : pstate <= 3'd6; // wait for Level 2 9'bx1_0xxx_110 : pstate <= 3'd0; // THAT'S ABORT ! 9'bx1_10xx_110 : pstate <= 3'd7; // Update neccesary : R=0 9'bx1_110x_110 : pstate <= 3'd0; // all ok - end 9'bx1_111x_110 : pstate <= 3'd7; // Update neccesary : M=0 9'bxx_xxx0_111 : pstate <= 3'd7; // write must wait 9'bxx_xxx1_111 : pstate <= 3'd0; // continues to end of DRAM write default : pstate <= 3'd0; endcase assign pte_acc = pstate[2]; assign level1 = ~pstate[1]; assign level2 = pstate[1]; assign valid_a = (ZTEST & RWVAL[1]) ? (cap_dat[2] & (cap_dat[1] | ~RWVAL[0]) & ~cap_dat[0] & level1) : ~cap_dat[0]; // not do_zt because of icp_acc in ABORT assign ABORT = mem_done & valid_a & ~icp_acc; assign PROTECT = ((mem_done & prot_i & ~icp_acc) | PROT_ERROR) & ~(ZTEST & RWVAL[1]); // no Protection-Error at RDVAL/WRVAL assign IACC_STAT[1] = mem_done & ~cap_dat[0] & icp_acc; assign IACC_STAT[2] = level1; assign IACC_STAT[3] = mem_done & prot_i & icp_acc; assign ABO_LEVEL1 = level1; // is stored in case of ABORT in ADDR_UNIT assign rd_level2 = (pstate == 3'd5) | (mem_done & (pstate == 3'd4) & refer & valid); assign WR_MRAM = mem_done & (pstate == 3'd6) & valid & ~icp_acc & ~ZTEST; assign wr_icmram = mem_done & (pstate == 3'd6) & valid & icp_acc; // Signals to the Instruction Cache // pte_acc combined with icp_acc for STATISTIK. assign IC_SIGS = {(pte_acc & icp_acc),wr_icmram}; assign PTE_MUX = pte_go | (pte_acc & ~pstate[1]); assign pte_puls = mem_done & pte_acc & ~pstate[1]; assign PTE_STAT = {(pte_puls & icp_acc),(pte_puls & ~icp_acc)}; // only for statistic assign PD_MUX = ((pstate == 3'd4) & mem_done & valid & ~refer) // switch data-MUX, write level 1 too | ((pstate == 3'd6) & mem_done & valid & (~refer | modi)) // write level 2 | (((pstate == 3'd5) | (pstate == 3'd7)) & ~pte_run_wr); assign pte_wr_sig = ENWR & PD_MUX; always @(posedge BCLK) pte_run_wr <= pte_wr_sig; // Ok-Signal for pstate State-machine assign PKEEP = (pstate == 3'd6) | ((pstate == 3'd7) & ~pte_run_wr); // keep the DRAM address // If there is a PTE still in the data cache it must be deleted. If MMU Bits are set by the pte engine a following // READ would deliver wrong data if cache hit. Therefore access of the Tags. always @(posedge BCLK or negedge BRESET) if (!BRESET) ko_state <= 3'b000; else casex ({kostart,ko_state}) 4'b0_000 : ko_state <= 3'b000; 4'b1_000 : ko_state <= 3'b110; 4'bx_110 : ko_state <= 3'b111; 4'bx_111 : ko_state <= 3'b100; 4'bx_100 : ko_state <= 3'b000; default : ko_state <= 3'b000; endcase assign kostart = pte_go | rd_level2; // ko_state[2] suppresses ACC_OK at READ assign run_dc = (~ko_state[2] | QWATWO) & ~dma_run; // Bugfix of 7.10.2015 assign KOMUX = ko_state[1] | DMA_MUX; assign KDET = ko_state[0] | dma_kdet; assign HIT_ALL = MMU_HIT & CA_HIT & run_dc & ~pte_acc; // for Update "Last-Set" , MMU_HIT contains ZUGRIFF always @(posedge BCLK or negedge BRESET) if (!BRESET) card_flag <= 1'b0; else card_flag <= (do_ca_rd & ~rd_rdy) | (card_flag & ~MDONE); assign CUPDATE = card_flag & USE_CA & MDONE; always @(posedge BCLK) rd_rdy <= card_flag & MDONE; // The cache RAM can not provide fast enough the data after an Update. In this case a secondary data path is activated assign AUX_DAT = rd_rdy; // DRAM interface : always @(posedge BCLK) DRAM_WR <= wr_dram | pte_wr_sig; // pulse always @(posedge BCLK) if (dram_go) DRAM_ACC <= 1'b1; else DRAM_ACC <= DRAM_ACC & ~MDONE & BRESET; // IO interface : always @(posedge BCLK) begin if (IO_ACC) IO_RD <= READ; else IO_RD <= IO_RD & ~IO_READY & BRESET; if (IO_ACC) IO_WR <= WRITE; else IO_WR <= IO_WR & ~IO_READY & BRESET; end assign io_busy = IO_RD | IO_WR | rd_done; // access is gone in next clock cycle, therefore blocked with "rd_done" always @(posedge BCLK) rd_done <= IO_RD & IO_READY; // For READ one clock later for data to come through assign dma = ICTODC[2]; // external request HOLD after FF in ICACHE always @(posedge BCLK) dma_run <= (dma_go | (dma_run & dma)) & BRESET; // stops the data access until HOLD becomes inactive assign HLDA = ~(ICTODC[1] & dma_run); // Signal for system that the CPU has stopped accesses always @(posedge BCLK) dma_kdet <= FILLRAM; assign DMA_MUX = FILLRAM | dma_kdet; // global feedback to ADDR_UNIT, early feedback to Op-Dec : you can continue assign ACC_OK = ZTEST ? (~VIRTUELL | zt_ok) : (IO_SPACE ? ((IO_ACC & WRITE) | rd_done) : (wr_dram | (READ & MMU_HIT & rd_ende & run_dc)) ); // PTB1 and PTB0 always @(posedge BCLK) if (PTB_WR && !PTB_SEL) ptb0 <= CPU_OUT[27:12]; always @(posedge BCLK) if (PTB_WR && PTB_SEL) ptb1 <= CPU_OUT[27:12]; always @(posedge BCLK) NEW_PTB <= PTB_WR; // to MMU Update Block always @(posedge BCLK) if (PTB_WR) PTB_ONE <= PTB_SEL; assign ptb10 = SEL_PTB1 ? ptb1 : ptb0; // Address multiplex between ICACHE=1 and DCACHE=0 : always @(posedge BCLK) if (pte_go) icp_acc <= do_ic_p; assign pte_sel = pte_go ? do_ic_p : icp_acc; assign virtual_adr = pte_sel ? IC_VA : VADR_R; // The 2 Address-LSB's : no full access : USE_CA = 0 assign PTE_ADR = rd_level2 ? {CAPDAT[27:12],virtual_adr[21:12],2'b00} : {ptb10,virtual_adr[31:22],2'b00}; // PTE_DAT[8] is used for update of MMU_RAM. assign pte_dat_8 = (level2 & WRITE & write_ok & ~icp_acc) | CAPDAT[8]; always @(posedge BCLK) pte_modi = pte_dat_8; assign PTE_DAT = {4'h3,CAPDAT[15:9],pte_modi,1'b1,CAPDAT[6:0]}; // the top 4 bits are Byte-Enable // The data for the MMU-RAM : 24 Bits , [6]=Cache Inhibit assign MMU_DIN = {pl_dat,pte_dat_8,CAPDAT[6],CAPDAT[31:12]}; // Protection field always @(posedge BCLK) if (mem_done && (pstate[2:0] == 3'd4)) prot_level1 <= cap_dat[2:1]; always @(prot_level1 or cap_dat) casex ({prot_level1,cap_dat[2]}) 3'b11_x : pl_dat = cap_dat[2:1]; 3'b10_1 : pl_dat = 2'b10; 3'b10_0 : pl_dat = cap_dat[2:1]; 3'b01_1 : pl_dat = 2'b01; 3'b01_0 : pl_dat = cap_dat[2:1]; 3'b00_x : pl_dat = 2'b00; endcase always @(USER or pl_dat) // is used if no PTE update is neccesary for M-Bit if writing is not allowed casex ({USER,pl_dat}) 3'b1_11 : write_ok = 1'b1; 3'b0_1x : write_ok = 1'b1; 3'b0_01 : write_ok = 1'b1; default : write_ok = 1'b0; endcase assign acc_level = level2 ? pl_dat : cap_dat[2:1]; assign user_ptw = icp_acc ? ICTODC[3] : USER; assign wr_ptw = ~icp_acc & (WRITE | RMW | (ZTEST & ~RWVAL[1])); // only data cache can write always @(acc_level or user_ptw or wr_ptw) case (acc_level) 2'b00 : prot_i = user_ptw | wr_ptw; 2'b01 : prot_i = user_ptw; 2'b10 : prot_i = user_ptw & wr_ptw; 2'b11 : prot_i = 1'b0; endcase endmodule
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