CSR状态控制寄存器，每个hart都有自己的CSR。对于每个hart，可以配置的状态寄存器是4k。CSR寄存器的功能见：https://www.cnblogs.com/mikewolf2002/p/11314583.html
CSR实现的rtl代码是e203_exu_csr.v,下面我们分析一下代码实现：
输出输入信号如下：
module e203_exu_csr( input csr_ena, //csr readwrite enable signal from alu，csr读写使能信号， input csr_wr_en, //csr write enable，csr写使能信号 input csr_rd_en, //csr read enable，csr读使能信号 input [11:0] csr_idx,//csr address index，csr地址索引 output tm_stop, //time stop, counterstop[1]，输出time counter是否停止 output core_cgstop,//not is used by isa, 0xbfe, self-defined, core clock gating，核心clock gating设置 output tcm_cgstop,//not is used by isa, 0xbfe, Stop TCM clock gating, tight coupled memory，tcm 访问clock gating output itcm_nohold, //not is used by isa，itcm是否hold上一次的读数据 output mdv_nob2b, //not is used by isa，是否是两个临接的乘除指令 output [`E203_XLEN-1:0] read_csr_dat,//read return data from csr，从csr读取的数据 input [`E203_XLEN-1:0] wbck_csr_dat,//data write back to csr，写数据到csr input [`E203_HART_ID_W-1:0] core_mhartid, //point mhartid, if read mhartid register, return this value，e203只有一个核，所以为0 //mip register input ext_irq_r,//external interrupt，是否是外部中断请求 input sft_irq_r,//software interrupt 是否是软件中断请求 input tmr_irq_r,//time interrupt, 是否是计时器中断请求 output status_mie_r,//输出状态寄存器的mie值，表示是否使能全局中断 //interrupt enble value for mie
output mtie_r, //机器模式定时器中断是否屏蔽, mie.mtie位 output msie_r, //机器方式软件中断是否屏蔽， output meie_r, //机器模式外部中断是否屏蔽, mie.meie位//0x7b0 Debug Control and Status
//0x7b1 Debug PC
//0x7b2 Debug Scratch Register
//0x7a0 Trigger selection register
output wr_dcsr_ena , //debug 模式下，写csr 使能 output wr_dpc_ena , //debug模式下，pc写使能 output wr_dscratch_ena, //debug模式下，scratch写使能 input [`E203_XLEN-1:0] dcsr_r , //输入dcsr值 input [`E203_PC_SIZE-1:0] dpc_r , //输入dpc值 input [`E203_XLEN-1:0] dscratch_r, //输入dscratch值 output [`E203_XLEN-1:0] wr_csr_nxt , //=wbck_csr_dat; input dbg_mode, //debug模式 input dbg_stopcycle, //如果在debug模式，且置位这个信号，则停止perf counter计数 output u_mode, //输出当前的模式，如果为那个模式，则这个信号置1 output s_mode, output h_mode, output m_mode, input [`E203_ADDR_SIZE-1:0] cmt_badaddr, //输入异常指令或者异常访存地址到mtval/mbadaddr input cmt_badaddr_ena, //badaddr 使能信号 input [`E203_PC_SIZE-1:0] cmt_epc, //异常返回地址 input cmt_epc_ena, //epc使能信号 input [`E203_XLEN-1:0] cmt_cause, //异常原因输入 input cmt_cause_ena, //cause使能 input cmt_status_ena, //status使能 input cmt_instret_ena, //instret使能 input cmt_mret_ena, //mret使能 output[`E203_PC_SIZE-1:0] csr_epc_r, //输出epc值，异常地址 output[`E203_PC_SIZE-1:0] csr_dpc_r, //输出dpc，debug模式的pc值 output[`E203_XLEN-1:0] csr_mtvec_r, //输出异常模式基地址 input clk_aon, //常开时钟信号，不会受clock gating影响 input clk, //时钟信号 input rst_n //复位信号 );
E203仅支持机器模式，所以priv_mode=2’b11。接着实现mstatus的rtl代码
wire wbck_csr_wen = csr_wr_en & csr_ena ;
wire read_csr_ena = csr_rd_en & csr_ena ;
wire [1:0] priv_mode = u_mode ? 2'b00 :
s_mode ? 2'b01 :
h_mode ? 2'b10 :
m_mode ? 2'b11 :
2'b11;
//0x000 URW ustatus User status register.
// * Since we support the user-level interrupt, hence we need to support UIE
//0x300 MRW mstatus Machine status register.
wire sel_ustatus = (csr_idx == 12'h000);
wire sel_mstatus = (csr_idx == 12'h300);
wire rd_ustatus = sel_ustatus & csr_rd_en;
wire rd_mstatus = sel_mstatus & csr_rd_en;
wire wr_ustatus = sel_ustatus & csr_wr_en;
wire wr_mstatus = sel_mstatus & csr_wr_en;
/////////////////////////////////////////////////////////////////////
// Note: the below implementation only apply to Machine-mode config,
// if other mode is also supported, these logics need to be updated
//////////////////////////
// Implement MPIE field
//
wire status_mpie_r;
// The MPIE Feilds will be updates when: //在中断发生或者中断完成，返回时候，或者直接写该寄存器时候，使能该寄存器 wire status_mpie_ena = // The CSR is written by CSR instructions (wr_mstatus & wbck_csr_wen) | // The MRET instruction commited cmt_mret_ena | // The Trap is taken cmt_status_ena; wire status_mpie_nxt = // See Priv SPEC: // When a trap is taken from privilege mode y into privilege // mode x, xPIE is set to the value of xIE; // So, When the Trap is taken, the MPIE is updated with the current MIE value cmt_status_ena ? status_mie_r : //进入中断的时候，保存mie的值。 // See Priv SPEC: // When executing an xRET instruction, supposing xPP holds the value y, xIE // is set to xPIE; the privilege mode is changed to y; // xPIE is set to 1; // So, When the MRET instruction commited, the MPIE is updated with 1 cmt_mret_ena ? 1'b1 : //从中断返回时候更新为0 // When the CSR is written by CSR instructions (wr_mstatus & wbck_csr_wen) ? wbck_csr_dat[7] : // MPIE is in field 7 of mstatus status_mpie_r; // Unchanged sirv_gnrl_dfflr #(1) status_mpie_dfflr (status_mpie_ena, status_mpie_nxt, status_mpie_r, clk, rst_n); ////////////////////////// // Implement MIE field // // The MIE Feilds will be updates same as MPIE wire status_mie_ena = status_mpie_ena; wire status_mie_nxt = // See Priv SPEC: // When a trap is taken from privilege mode y into privilege // mode x, xPIE is set to the value of xIE, // xIE is set to 0; // So, When the Trap is taken, the MIE is updated with 0 cmt_status_ena ? 1'b0 : //进入中断时候，关闭中断 // See Priv SPEC: // When executing an xRET instruction, supposing xPP holds the value y, xIE // is set to xPIE; the privilege mode is changed to y, xPIE is set to 1; // So, When the MRET instruction commited, the MIE is updated with MPIE cmt_mret_ena ? status_mpie_r : //从中断返回时候，恢复保存在mpie中的值。 // When the CSR is written by CSR instructions (wr_mstatus & wbck_csr_wen) ? wbck_csr_dat[3] : // MIE is in field 3 of mstatus status_mie_r; // Unchanged sirv_gnrl_dfflr #(1) status_mie_dfflr (status_mie_ena, status_mie_nxt, status_mie_r, clk, rst_n); ////////////////////////// // Implement SD field // // See Priv SPEC: // The SD bit is read-only // And is set when either the FS or XS bits encode a Dirty // state (i.e., SD=((FS==11) OR (XS==11))).
//因为没有浮点单元和协处理器，fs，xs域都为0 wire [1:0] status_fs_r; wire [1:0] status_xs_r; wire status_sd_r = (status_fs_r == 2'b11) | (status_xs_r == 2'b11); ////////////////////////// // Implement XS field // // See Priv SPEC: // XS field is read-only // The XS field represents a summary of all extensions' status // But in E200 we implement XS exactly same as FS to make it usable by software to // disable extended accelerators // If no EAI coprocessor interface configured, the XS is just hardwired to 0 assign status_xs_r = 2'b0; ////////////////////////// // Implement FS field // `ifndef E203_HAS_FPU // If no FPU configured, the FS is just hardwired to 0 assign status_fs_r = 2'b0; `endif ////////////////////////// // Pack to the full mstatus register // wire [`E203_XLEN-1:0] status_r; assign status_r[31] = status_sd_r; //SD assign status_r[30:23] = 8'b0; // Reserved assign status_r[22:17] = 6'b0; // TSR--MPRV assign status_r[16:15] = status_xs_r; // XS assign status_r[14:13] = status_fs_r; // FS assign status_r[12:11] = 2'b11; // MPP assign status_r[10:9] = 2'b0; // Reserved assign status_r[8] = 1'b0; // SPP assign status_r[7] = status_mpie_r; // MPIE assign status_r[6] = 1'b0; // Reserved assign status_r[5] = 1'b0; // SPIE assign status_r[4] = 1'b0; // UPIE assign status_r[3] = status_mie_r; // MIE assign status_r[2] = 1'b0; // Reserved assign status_r[1] = 1'b0; // SIE assign status_r[0] = 1'b0; // UIE wire [`E203_XLEN-1:0] csr_mstatus = status_r;
mie/mip rtl实现
//0x004 URW uie User interrupt-enable register. // * Since we dont delegate interrupt to user mode, hence it is as all 0s //0x304 MRW mie Machine interrupt-enable register. wire sel_mie = (csr_idx == 12'h304); wire rd_mie = sel_mie & csr_rd_en; wire wr_mie = sel_mie & csr_wr_en; wire mie_ena = wr_mie & wbck_csr_wen; wire [`E203_XLEN-1:0] mie_r; wire [`E203_XLEN-1:0] mie_nxt; assign mie_nxt[31:12] = 20'b0; assign mie_nxt[11] = wbck_csr_dat[11];//MEIE assign mie_nxt[10:8] = 3'b0; assign mie_nxt[ 7] = wbck_csr_dat[ 7];//MTIE assign mie_nxt[6:4] = 3'b0; assign mie_nxt[ 3] = wbck_csr_dat[ 3];//MSIE assign mie_nxt[2:0] = 3'b0; sirv_gnrl_dfflr #(`E203_XLEN) mie_dfflr (mie_ena, mie_nxt, mie_r, clk, rst_n); wire [`E203_XLEN-1:0] csr_mie = mie_r; assign meie_r = csr_mie[11]; assign mtie_r = csr_mie[ 7]; assign msie_r = csr_mie[ 3]; //0x044 URW uip User interrupt pending. // We dont support delegation scheme, so no need to support the uip //0x344 MRW mip Machine interrupt pending wire sel_mip = (csr_idx == 12'h344); wire rd_mip = sel_mip & csr_rd_en; //wire wr_mip = sel_mip & csr_wr_en; // The MxIP is read-only wire meip_r; wire msip_r; wire mtip_r; sirv_gnrl_dffr #(1) meip_dffr (ext_irq_r, meip_r, clk, rst_n); sirv_gnrl_dffr #(1) msip_dffr (sft_irq_r, msip_r, clk, rst_n); sirv_gnrl_dffr #(1) mtip_dffr (tmr_irq_r, mtip_r, clk, rst_n); wire [`E203_XLEN-1:0] ip_r; assign ip_r[31:12] = 20'b0; assign ip_r[11] = meip_r; assign ip_r[10:8] = 3'b0; assign ip_r[ 7] = mtip_r; assign ip_r[6:4] = 3'b0; assign ip_r[ 3] = msip_r; assign ip_r[2:0] = 3'b0; wire [`E203_XLEN-1:0] csr_mip = ip_r;
mtvec和mscratch rtl实现
//0x005 URW utvec User trap handler base address. // We dont support user trap, so no utvec needed //0x305 MRW mtvec Machine trap-handler base address. wire sel_mtvec = (csr_idx == 12'h305); wire rd_mtvec = csr_rd_en & sel_mtvec; `ifdef E203_SUPPORT_MTVEC //{ wire wr_mtvec = sel_mtvec & csr_wr_en; wire mtvec_ena = (wr_mtvec & wbck_csr_wen); wire [`E203_XLEN-1:0] mtvec_r; wire [`E203_XLEN-1:0] mtvec_nxt = wbck_csr_dat; sirv_gnrl_dfflr #(`E203_XLEN) mtvec_dfflr (mtvec_ena, mtvec_nxt, mtvec_r, clk, rst_n); wire [`E203_XLEN-1:0] csr_mtvec = mtvec_r; `else//}{ // THe vector table base is a configurable parameter, so we dont support writeable to it wire [`E203_XLEN-1:0] csr_mtvec = `E203_MTVEC_TRAP_BASE; `endif//} assign csr_mtvec_r = csr_mtvec; //0x340 MRW mscratch wire sel_mscratch = (csr_idx == 12'h340); wire rd_mscratch = sel_mscratch & csr_rd_en; `ifdef E203_SUPPORT_MSCRATCH //{ wire wr_mscratch = sel_mscratch & csr_wr_en; wire mscratch_ena = (wr_mscratch & wbck_csr_wen); wire [`E203_XLEN-1:0] mscratch_r; wire [`E203_XLEN-1:0] mscratch_nxt = wbck_csr_dat; sirv_gnrl_dfflr #(`E203_XLEN) mscratch_dfflr (mscratch_ena, mscratch_nxt, mscratch_r, clk, rst_n); wire [`E203_XLEN-1:0] csr_mscratch = mscratch_r; `else//}{ wire [`E203_XLEN-1:0] csr_mscratch = `E203_XLEN'b0; `endif//}
mcycle/mcycleh/minstret/minstreth/counterstop/cgstop/itcmnohold/mdvnob2b等的rtl实现。
// 0xB00 MRW mcycle // 0xB02 MRW minstret // 0xB80 MRW mcycleh // 0xB82 MRW minstreth wire sel_mcycle = (csr_idx == 12'hB00); wire sel_mcycleh = (csr_idx == 12'hB80); wire sel_minstret = (csr_idx == 12'hB02); wire sel_minstreth = (csr_idx == 12'hB82); // 0xBFF MRW counterstop // This register is our self-defined register to stop // the cycle/time/instret counters to save dynamic powers wire sel_counterstop = (csr_idx == 12'hBFF);// This address is not used by ISA // 0xBFE MRW mcgstop // This register is our self-defined register to disable the // automaticall clock gating for CPU logics for debugging purpose wire sel_mcgstop = (csr_idx == 12'hBFE);// This address is not used by ISA // 0xBFD MRW itcmnohold // This register is our self-defined register to disble the // ITCM SRAM output holdup feature, if set, then we assume // ITCM SRAM output cannot holdup last read value wire sel_itcmnohold = (csr_idx == 12'hBFD);// This address is not used by ISA // 0xBF0 MRW mdvnob2b // This register is our self-defined register to disble the // Mul/div back2back feature wire sel_mdvnob2b = (csr_idx == 12'hBF0);// This address is not used by ISA wire rd_mcycle = csr_rd_en & sel_mcycle ; wire rd_mcycleh = csr_rd_en & sel_mcycleh ; wire rd_minstret = csr_rd_en & sel_minstret ; wire rd_minstreth = csr_rd_en & sel_minstreth; wire rd_itcmnohold = csr_rd_en & sel_itcmnohold; wire rd_mdvnob2b = csr_rd_en & sel_mdvnob2b; wire rd_counterstop = csr_rd_en & sel_counterstop; wire rd_mcgstop = csr_rd_en & sel_mcgstop; `ifdef E203_SUPPORT_MCYCLE_MINSTRET //{ wire wr_mcycle = csr_wr_en & sel_mcycle ; wire wr_mcycleh = csr_wr_en & sel_mcycleh ; wire wr_minstret = csr_wr_en & sel_minstret ; wire wr_minstreth = csr_wr_en & sel_minstreth; wire wr_itcmnohold = csr_wr_en & sel_itcmnohold ; wire wr_mdvnob2b = csr_wr_en & sel_mdvnob2b ; wire wr_counterstop = csr_wr_en & sel_counterstop; wire wr_mcgstop = csr_wr_en & sel_mcgstop ; wire mcycle_wr_ena = (wr_mcycle & wbck_csr_wen); wire mcycleh_wr_ena = (wr_mcycleh & wbck_csr_wen); wire minstret_wr_ena = (wr_minstret & wbck_csr_wen); wire minstreth_wr_ena = (wr_minstreth & wbck_csr_wen); wire itcmnohold_wr_ena = (wr_itcmnohold & wbck_csr_wen); wire mdvnob2b_wr_ena = (wr_mdvnob2b & wbck_csr_wen); wire counterstop_wr_ena = (wr_counterstop & wbck_csr_wen); wire mcgstop_wr_ena = (wr_mcgstop & wbck_csr_wen); wire [`E203_XLEN-1:0] mcycle_r ; wire [`E203_XLEN-1:0] mcycleh_r ; wire [`E203_XLEN-1:0] minstret_r ; wire [`E203_XLEN-1:0] minstreth_r; wire cy_stop; wire ir_stop; wire stop_cycle_in_dbg = dbg_stopcycle & dbg_mode; wire mcycle_ena = mcycle_wr_ena | ((~cy_stop) & (~stop_cycle_in_dbg) & (1'b1)); wire mcycleh_ena = mcycleh_wr_ena | ((~cy_stop) & (~stop_cycle_in_dbg) & ((mcycle_r == (~(`E203_XLEN'b0))))); wire minstret_ena = minstret_wr_ena | ((~ir_stop) & (~stop_cycle_in_dbg) & (cmt_instret_ena)); wire minstreth_ena = minstreth_wr_ena | ((~ir_stop) & (~stop_cycle_in_dbg) & ((cmt_instret_ena & (minstret_r == (~(`E203_XLEN'b0)))))); //auto increment wire [`E203_XLEN-1:0] mcycle_nxt = mcycle_wr_ena ? wbck_csr_dat : (mcycle_r + 1'b1); wire [`E203_XLEN-1:0] mcycleh_nxt = mcycleh_wr_ena ? wbck_csr_dat : (mcycleh_r + 1'b1); wire [`E203_XLEN-1:0] minstret_nxt = minstret_wr_ena ? wbck_csr_dat : (minstret_r + 1'b1); wire [`E203_XLEN-1:0] minstreth_nxt = minstreth_wr_ena ? wbck_csr_dat : (minstreth_r + 1'b1); //We need to use the always-on clock for this counter sirv_gnrl_dfflr #(`E203_XLEN) mcycle_dfflr (mcycle_ena, mcycle_nxt, mcycle_r , clk_aon, rst_n); sirv_gnrl_dfflr #(`E203_XLEN) mcycleh_dfflr (mcycleh_ena, mcycleh_nxt, mcycleh_r , clk_aon, rst_n); sirv_gnrl_dfflr #(`E203_XLEN) minstret_dfflr (minstret_ena, minstret_nxt, minstret_r , clk, rst_n); sirv_gnrl_dfflr #(`E203_XLEN) minstreth_dfflr (minstreth_ena, minstreth_nxt, minstreth_r, clk, rst_n); wire [`E203_XLEN-1:0] counterstop_r; wire counterstop_ena = counterstop_wr_ena; wire [`E203_XLEN-1:0] counterstop_nxt = {29'b0,wbck_csr_dat[2:0]};// Only LSB 3bits are useful sirv_gnrl_dfflr #(`E203_XLEN) counterstop_dfflr (counterstop_ena, counterstop_nxt, counterstop_r, clk, rst_n); wire [`E203_XLEN-1:0] csr_mcycle = mcycle_r; wire [`E203_XLEN-1:0] csr_mcycleh = mcycleh_r; wire [`E203_XLEN-1:0] csr_minstret = minstret_r; wire [`E203_XLEN-1:0] csr_minstreth = minstreth_r; wire [`E203_XLEN-1:0] csr_counterstop = counterstop_r; `else//}{ wire [`E203_XLEN-1:0] csr_mcycle = `E203_XLEN'b0; wire [`E203_XLEN-1:0] csr_mcycleh = `E203_XLEN'b0; wire [`E203_XLEN-1:0] csr_minstret = `E203_XLEN'b0; wire [`E203_XLEN-1:0] csr_minstreth = `E203_XLEN'b0; wire [`E203_XLEN-1:0] csr_counterstop = `E203_XLEN'b0; `endif//} wire [`E203_XLEN-1:0] itcmnohold_r; wire itcmnohold_ena = itcmnohold_wr_ena; wire [`E203_XLEN-1:0] itcmnohold_nxt = {31'b0,wbck_csr_dat[0]};// Only LSB 1bits are useful sirv_gnrl_dfflr #(`E203_XLEN) itcmnohold_dfflr (itcmnohold_ena, itcmnohold_nxt, itcmnohold_r, clk, rst_n); wire [`E203_XLEN-1:0] csr_itcmnohold = itcmnohold_r; wire [`E203_XLEN-1:0] mdvnob2b_r; wire mdvnob2b_ena = mdvnob2b_wr_ena; wire [`E203_XLEN-1:0] mdvnob2b_nxt = {31'b0,wbck_csr_dat[0]};// Only LSB 1bits are useful sirv_gnrl_dfflr #(`E203_XLEN) mdvnob2b_dfflr (mdvnob2b_ena, mdvnob2b_nxt, mdvnob2b_r, clk, rst_n); wire [`E203_XLEN-1:0] csr_mdvnob2b = mdvnob2b_r; assign cy_stop = counterstop_r[0];// Stop CYCLE counter assign tm_stop = counterstop_r[1];// Stop TIME counter assign ir_stop = counterstop_r[2];// Stop INSTRET counter,instruction number counter assign itcm_nohold = itcmnohold_r[0];// ITCM no-hold up feature assign mdv_nob2b = mdvnob2b_r[0];// Mul/Div no back2back feature wire [`E203_XLEN-1:0] mcgstop_r; wire mcgstop_ena = mcgstop_wr_ena; wire [`E203_XLEN-1:0] mcgstop_nxt = {30'b0,wbck_csr_dat[1:0]};// Only LSB 2bits are useful sirv_gnrl_dfflr #(`E203_XLEN) mcgstop_dfflr (mcgstop_ena, mcgstop_nxt, mcgstop_r, clk, rst_n); wire [`E203_XLEN-1:0] csr_mcgstop = mcgstop_r; assign core_cgstop = mcgstop_r[0];// Stop Core clock gating assign tcm_cgstop = mcgstop_r[1];// Stop TCM clock gating
mepc/mcause/mbadaddr/misa等的rtl实现。
//0x041 URW uepc User exception program counter.
// We dont support user trap, so no uepc needed
//0x341 MRW mepc Machine exception program counter.
wire sel_mepc = (csr_idx == 12'h341);
wire rd_mepc = sel_mepc & csr_rd_en;
wire wr_mepc = sel_mepc & csr_wr_en;
wire epc_ena = (wr_mepc & wbck_csr_wen) | cmt_epc_ena;
wire [`E203_PC_SIZE-1:0] epc_r;
wire [`E203_PC_SIZE-1:0] epc_nxt;
assign epc_nxt[`E203_PC_SIZE-1:1] = cmt_epc_ena ? cmt_epc[`E203_PC_SIZE-1:1] : wbck_csr_dat[`E203_PC_SIZE-1:1];
assign epc_nxt[0] = 1'b0;// Must not hold PC which will generate the misalign exception according to ISA
sirv_gnrl_dfflr #(`E203_PC_SIZE) epc_dfflr (epc_ena, epc_nxt, epc_r, clk, rst_n);
wire [`E203_XLEN-1:0] csr_mepc;
wire dummy_0;
assign {dummy_0,csr_mepc} = {{`E203_XLEN+1-`E203_PC_SIZE{1'b0}},epc_r};
assign csr_epc_r = csr_mepc;
//0x042 URW ucause User trap cause.
// We dont support user trap, so no ucause needed
//0x342 MRW mcause Machine trap cause.
wire sel_mcause = (csr_idx == 12'h342);
wire rd_mcause = sel_mcause & csr_rd_en;
wire wr_mcause = sel_mcause & csr_wr_en;
wire cause_ena = (wr_mcause & wbck_csr_wen) | cmt_cause_ena;
wire [`E203_XLEN-1:0] cause_r;
wire [`E203_XLEN-1:0] cause_nxt;
assign cause_nxt[31] = cmt_cause_ena ? cmt_cause[31] : wbck_csr_dat[31];
assign cause_nxt[30:4] = 27'b0;
assign cause_nxt[3:0] = cmt_cause_ena ? cmt_cause[3:0] : wbck_csr_dat[3:0];
sirv_gnrl_dfflr #(`E203_XLEN) cause_dfflr (cause_ena, cause_nxt, cause_r, clk, rst_n);
wire [`E203_XLEN-1:0] csr_mcause = cause_r;
//0x043 URW ubadaddr User bad address.
// We dont support user trap, so no ubadaddr needed
//0x343 MRW mbadaddr Machine bad address.
wire sel_mbadaddr = (csr_idx == 12'h343);
wire rd_mbadaddr = sel_mbadaddr & csr_rd_en;
wire wr_mbadaddr = sel_mbadaddr & csr_wr_en;
wire cmt_trap_badaddr_ena = cmt_badaddr_ena;
wire badaddr_ena = (wr_mbadaddr & wbck_csr_wen) | cmt_trap_badaddr_ena;
wire [`E203_ADDR_SIZE-1:0] badaddr_r;
wire [`E203_ADDR_SIZE-1:0] badaddr_nxt;
assign badaddr_nxt = cmt_trap_badaddr_ena ? cmt_badaddr : wbck_csr_dat[`E203_ADDR_SIZE-1:0];
sirv_gnrl_dfflr #(`E203_ADDR_SIZE) badaddr_dfflr (badaddr_ena, badaddr_nxt, badaddr_r, clk, rst_n);
wire [`E203_XLEN-1:0] csr_mbadaddr;
wire dummy_1;
assign {dummy_1,csr_mbadaddr} = {{`E203_XLEN+1-`E203_ADDR_SIZE{1'b0}},badaddr_r};
// We dont support the delegation scheme, so no need to implement
// delegete registers
//0x301 MRW misa ISA and extensions
wire sel_misa = (csr_idx == 12'h301);
wire rd_misa = sel_misa & csr_rd_en;
// Only implemented the M mode, IMC or EMC
wire [`E203_XLEN-1:0] csr_misa = {
2'b1
,4'b0 //WIRI
,1'b0 // 25 Z Reserved
,1'b0 // 24 Y Reserved
,1'b0 // 23 X Non-standard extensions present
,1'b0 // 22 W Reserved
,1'b0 // 21 V Tentatively reserved for Vector extension 20 U User mode implemented
,1'b0 // 20 U User mode implemented
,1'b0 // 19 T Tentatively reserved for Transactional Memory extension
,1'b0 // 18 S Supervisor mode implemented
,1'b0 // 17 R Reserved
,1'b0 // 16 Q Quad-precision floating-point extension
,1'b0 // 15 P Tentatively reserved for Packed-SIMD extension
,1'b0 // 14 O Reserved
,1'b0 // 13 N User-level interrupts supported
,1'b1 // 12 M Integer Multiply/Divide extension
,1'b0 // 11 L Tentatively reserved for Decimal Floating-Point extension
,1'b0 // 10 K Reserved
,1'b0 // 9 J Reserved
`ifdef E203_RFREG_NUM_IS_32
,1'b1 // 8 I RV32I/64I/128I base ISA
`else
,1'b0
`endif
,1'b0 // 7 H Hypervisor mode implemented
,1'b0 // 6 G Additional standard extensions present
`ifndef E203_HAS_FPU//{
,1'b0 // 5 F Single-precision floating-point extension
`endif//
`ifdef E203_RFREG_NUM_IS_32
,1'b0 // 4 E RV32E base ISA
`else
,1'b1 //
`endif
`ifndef E203_HAS_FPU//{
,1'b0 // 3 D Double-precision floating-point extension
`endif//
,1'b1 // 2 C Compressed extension
,1'b0 // 1 B Tentatively reserved for Bit operations extension
`ifdef E203_SUPPORT_AMO//{
,1'b1 // 0 A Atomic extension
`endif//E203_SUPPORT_AMO}
`ifndef E203_SUPPORT_AMO//{
,1'b0 // 0 A Atomic extension
`endif//}
};
//Machine Information Registers
//0xF11 MRO mvendorid Vendor ID.
//0xF12 MRO marchid Architecture ID.
//0xF13 MRO mimpid Implementation ID.
//0xF14 MRO mhartid Hardware thread ID.
wire [`E203_XLEN-1:0] csr_mvendorid = `E203_XLEN'h`E203_MVENDORID;
wire [`E203_XLEN-1:0] csr_marchid = `E203_XLEN'h`E203_MARCHID ;
wire [`E203_XLEN-1:0] csr_mimpid = `E203_XLEN'h`E203_MIMPID ;
wire [`E203_XLEN-1:0] csr_mhartid = {{`E203_XLEN-`E203_HART_ID_W{1'b0}},core_mhartid};
wire rd_mvendorid = csr_rd_en & (csr_idx == 12'hF11);
wire rd_marchid = csr_rd_en & (csr_idx == 12'hF12);
wire rd_mimpid = csr_rd_en & (csr_idx == 12'hF13);
wire rd_mhartid = csr_rd_en & (csr_idx == 12'hF14);
//0x7b0 Debug Control and Status
//0x7b1 Debug PC
//0x7b2 Debug Scratch Register
//0x7a0 Trigger selection register
wire sel_dcsr = (csr_idx == 12'h7b0);
wire sel_dpc = (csr_idx == 12'h7b1);
wire sel_dscratch = (csr_idx == 12'h7b2);
wire rd_dcsr = dbg_mode & csr_rd_en & sel_dcsr ;
wire rd_dpc = dbg_mode & csr_rd_en & sel_dpc ;
wire rd_dscratch = dbg_mode & csr_rd_en & sel_dscratch;
assign wr_dcsr_ena = dbg_mode & csr_wr_en & sel_dcsr ;
assign wr_dpc_ena = dbg_mode & csr_wr_en & sel_dpc ;
assign wr_dscratch_ena = dbg_mode & csr_wr_en & sel_dscratch;
assign wr_csr_nxt = wbck_csr_dat;
wire [`E203_XLEN-1:0] csr_dcsr = dcsr_r ;
`ifdef E203_PC_SIZE_IS_16
wire [`E203_XLEN-1:0] csr_dpc = {{`E203_XLEN-`E203_PC_SIZE{1'b0}},dpc_r};
`endif
`ifdef E203_PC_SIZE_IS_24
wire [`E203_XLEN-1:0] csr_dpc = {{`E203_XLEN-`E203_PC_SIZE{1'b0}},dpc_r};
`endif
`ifdef E203_PC_SIZE_IS_32
wire [`E203_XLEN-1:0] csr_dpc = dpc_r ;
`endif
wire [`E203_XLEN-1:0] csr_dscratch = dscratch_r;
assign csr_dpc_r = dpc_r;
下面是我的写的一个testbench，
`include "e203_defines.v" module e203_exu_csr_tb; reg csr_ena; //csr readwrite enable signal from alu reg csr_wr_en; //csr write enable reg csr_rd_en; //csr read enable reg [11:0] csr_idx;//csr address index wire tm_stop; wire core_cgstop; wire tcm_cgstop; wire itcm_nohold; wire mdv_nob2b; wire [`E203_XLEN-1:0] read_csr_dat; reg [`E203_XLEN-1:0] wbck_csr_dat; reg [`E203_HART_ID_W-1:0] core_mhartid; reg ext_irq_r; reg sft_irq_r; reg tmr_irq_r; wire status_mie_r; wire mtie_r; wire msie_r; wire meie_r; wire wr_dcsr_ena ; wire wr_dpc_ena ; wire wr_dscratch_ena; reg [`E203_XLEN-1:0] dcsr_r ; reg [`E203_PC_SIZE-1:0] dpc_r ; reg [`E203_XLEN-1:0] dscratch_r; wire [`E203_XLEN-1:0] wr_csr_nxt ; reg dbg_mode; reg dbg_stopcycle; wire u_mode; wire s_mode; wire h_mode; wire m_mode; reg [`E203_ADDR_SIZE-1:0] cmt_badaddr; reg cmt_badaddr_ena; reg [`E203_PC_SIZE-1:0] cmt_epc; reg cmt_epc_ena; reg [`E203_XLEN-1:0] cmt_cause; reg cmt_cause_ena; reg cmt_status_ena; reg cmt_instret_ena; reg cmt_mret_ena; wire[`E203_PC_SIZE-1:0] csr_epc_r; wire[`E203_PC_SIZE-1:0] csr_dpc_r; wire[`E203_XLEN-1:0] csr_mtvec_r; reg clk=0; reg rst_n; e203_exu_csr mycsr( .csr_ena(csr_ena), .csr_wr_en(csr_wr_en), .csr_rd_en(csr_rd_en), .csr_idx(csr_idx), .tm_stop(tm_stop), .core_cgstop(core_cgstop), .tcm_cgstop(tcm_cgstop), .itcm_nohold(itcm_nohold), .mdv_nob2b(mdv_nob2b), .read_csr_dat(read_csr_dat), .wbck_csr_dat(wbck_csr_dat), .core_mhartid(core_mhartid), .ext_irq_r(ext_irq_r), .sft_irq_r(sft_irq_r), .tmr_irq_r(tmr_irq_r), .status_mie_r(status_mie_r), .mtie_r(mtie_r), .msie_r(msie_r), .meie_r(meie_r), .wr_dcsr_ena(wr_dcsr_ena), .wr_dpc_ena(wr_dpc_ena), .wr_dscratch_ena(wr_dscratch_ena), .dcsr_r(dcsr_r), .dpc_r(dpc_r), .dscratch_r(dscratch_r), .wr_csr_nxt(wr_csr_nxt), .dbg_mode(dbg_mode), .dbg_stopcycle(dbg_stopcycle), .u_mode(u_mode), .s_mode(s_mode), .h_mode(h_mode), .m_mode(m_mode), .cmt_badaddr(cmt_badaddr), .cmt_badaddr_ena(cmt_badaddr_ena), .cmt_epc(cmt_epc), .cmt_epc_ena(cmt_epc_ena), .cmt_cause(cmt_cause), .cmt_cause_ena(cmt_cause_ena), .cmt_status_ena(cmt_status_ena), .cmt_instret_ena(cmt_instret_ena), .cmt_mret_ena(cmt_mret_ena), .csr_epc_r(csr_epc_r), .csr_dpc_r(csr_dpc_r), .csr_mtvec_r(csr_mtvec_r), .clk_aon(clk), .clk(clk), .rst_n(rst_n) ); always #10 clk=~clk; initial begin rst_n = 1'b1; #20 rst_n= 1'b0; #20 rst_n=1'b1; csr_ena = 1'b1; csr_wr_en = 1'b1; csr_rd_en = 1'b0; csr_idx = 11'h300; //mstatus wbck_csr_dat = 32'h0001f888; core_mhartid = `E203_HART_ID_W'h0; ext_irq_r = 1'b0; sft_irq_r = 1'b0; tmr_irq_r = 1'b0; dcsr_r = `E203_XLEN'h5; dpc_r = `E203_PC_SIZE'h5; dscratch_r = `E203_XLEN'h5; dbg_mode = 1'b0; dbg_stopcycle= 1'b0; cmt_badaddr=`E203_ADDR_SIZE'h4; cmt_badaddr_ena = 1'b0; cmt_epc=`E203_PC_SIZE'h4; cmt_epc_ena = 1'b0; cmt_cause=`E203_XLEN'h4; cmt_cause_ena = 1'b0; cmt_status_ena = 1'b0; cmt_instret_ena = 1'b0; cmt_mret_ena = 1'b0; #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h80; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h888; csr_idx = 12'h304; //mie #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h800; csr_idx = 12'h344; //mip #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'hff; csr_idx = 12'h305; //mtvec #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'hff00; csr_idx = 12'h340; //mscratch #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h7; csr_idx = 12'hbff; //counterstop #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h3; csr_idx = 12'hbfe; //mcgstop #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h1; csr_idx = 12'hbfd; //itcmnohold #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h1; csr_idx = 12'hbf0; //mdvnob2b #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'h1; csr_idx = 12'h341; //mepc #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'haa; csr_idx = 12'h342; //mcasue #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b1; csr_rd_en = 1'b0; wbck_csr_dat = 32'hffff; csr_idx = 12'h343; //mbadaddr/mtval #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; csr_idx = 12'h301; //misa #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; csr_idx = 12'hf11; //mvendorid #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; csr_idx = 12'hf12; //marchid #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; csr_idx = 12'hf13; //mimpid #20 csr_wr_en = 1'b0; csr_rd_en = 1'b1; csr_idx = 12'hf14; //mhartid #100 $finish; end //initial // $monitor($time,,,"clk=%b,i_instr=0x%h,i_pc=%h",clk,i_instr,i_pc); initial begin //$dumpfile("dump.vcd"); //$dumpvars; $fsdbDumpfile("dump.fsdb"); $fsdbDumpvars("+all"); end endmodule
Makefile
# VCS flags, if want to use dump fsdb in verilog file, need to add args -fsdb, otherwise will be compiled fail VCS_FLAGS = -sverilog -full64 -fsdb -debug_all +v2k -timescale=1ns/1ns +define+DISABLE_SV_ASSERTION # Source files SRC_FILES = e203_exu_csr.v sirv_gnrl_dffs.v sirv_gnrl_xchecker.v e203_exu_csr_tb.v # Source directories INCDIR = +incdir+./ all: vcs $(VCS_FLAGS) $(INCDIR) $(SRC_FILES) clean: rm -rf ./csrc *.daidir ./csrc *.log *.vpd *.vdb simv* *.key *race.out* *vcd *fsdb debug: verdi -sv -ssf dump.fsdb -f verdi.f &