X-Git-Url: http://git.joshuawise.com/firearm.git/blobdiff_plain/b3bb2fb8d24456b2683c5bdb8b3b195d0f600a97..feb2b5beb6bd3dbeb10ce942e10fbdf5f3df261e:/Memory.v?ds=inline diff --git a/Memory.v b/Memory.v index 2b4b2a4..918c5d9 100644 --- a/Memory.v +++ b/Memory.v @@ -3,10 +3,8 @@ module Memory( input clk, input Nrst, - input [31:0] pc, - input [31:0] insn, - input [31:0] base, - input [31:0] offset, + + input flush, /* bus interface */ output reg [31:0] busaddr, @@ -15,111 +13,407 @@ module Memory( input rw_wait, output reg [31:0] wr_data, input [31:0] rd_data, + output reg [2:0] data_size, /* regfile interface */ output reg [3:0] st_read, input [31:0] st_data, + + /* Coprocessor interface */ + output reg cp_req, + input cp_ack, + input cp_busy, + output reg cp_rnw, /* 1 = read from CP, 0 = write to CP */ + input [31:0] cp_read, + output reg [31:0] cp_write, + + /* stage inputs */ + input inbubble, + input [31:0] pc, + input [31:0] insn, + input [31:0] op0, + input [31:0] op1, + input [31:0] op2, + input [31:0] spsr, + input [31:0] cpsr, + input write_reg, + input [3:0] write_num, + input [31:0] write_data, - /* writeback to base */ - output reg writeback, - output reg [3:0] regsel, - output reg [31:0] regdata, - - /* pc stuff */ + /* outputs */ + output reg outstall, + output reg outbubble, output reg [31:0] outpc, - output reg [31:0] newpc, + output reg [31:0] outinsn, + output reg out_write_reg = 1'b0, + output reg [3:0] out_write_num = 4'bxxxx, + output reg [31:0] out_write_data = 32'hxxxxxxxx, + output reg [31:0] outspsr = 32'hxxxxxxxx, + output reg [31:0] outcpsr = 32'hxxxxxxxx + ); - /* stall */ - output outstall, - output reg outbubble, - output reg flush -); + reg [31:0] addr, raddr, prev_raddr, next_regdata, next_outcpsr; + reg [31:0] prevaddr; + reg [3:0] next_regsel, cur_reg, prev_reg; + reg next_writeback; + + reg next_outbubble; + reg next_write_reg; + reg [3:0] next_write_num; + reg [31:0] next_write_data; + + reg [1:0] lsr_state = 2'b01, next_lsr_state; + reg [31:0] align_s1, align_s2, align_rddata; - reg [31:0] addr, raddr; - reg notdone = 1'b0; - reg inc_next = 1'b0; - wire [31:0] align_s1, align_s2, align_rddata; - assign outstall = rw_wait | notdone; + reg [1:0] lsrh_state = 2'b01, next_lsrh_state; + reg [31:0] lsrh_rddata; + reg [15:0] lsrh_rddata_s1; + reg [7:0] lsrh_rddata_s2; + + reg [15:0] regs, next_regs; + reg [2:0] lsm_state = 3'b001, next_lsm_state; + reg [5:0] offset, prev_offset, offset_sel; + + reg [31:0] swp_oldval, next_swp_oldval; + reg [1:0] swp_state = 2'b01, next_swp_state; + + always @(posedge clk) + begin + outpc <= pc; + outinsn <= insn; + outbubble <= next_outbubble; + out_write_reg <= next_write_reg; + out_write_num <= next_write_num; + out_write_data <= next_write_data; + regs <= next_regs; + prev_reg <= cur_reg; + prev_offset <= offset; + prev_raddr <= raddr; + outcpsr <= next_outcpsr; + outspsr <= spsr; + swp_state <= next_swp_state; + lsm_state <= next_lsm_state; + lsr_state <= next_lsr_state; + lsrh_state <= next_lsrh_state; + prevaddr <= addr; + end always @(*) begin - addr = 32'hxxxxxxxx; + addr = prevaddr; raddr = 32'hxxxxxxxx; rd_req = 1'b0; wr_req = 1'b0; wr_data = 32'hxxxxxxxx; busaddr = 32'hxxxxxxxx; + data_size = 3'bxxx; outstall = 1'b0; - casez(insn) - `DECODE_LDRSTR_UNDEFINED: begin end - `DECODE_LDRSTR: begin - addr = insn[23] ? base + offset : base - offset; /* up/down select */ - raddr = insn[24] ? base : addr; - busaddr = {raddr[31:2], 2'b0}; /* pre/post increment */ - rd_req = insn[20]; - wr_req = ~insn[20]; - if(!insn[20]) begin /* store */ - st_read = insn[15:12]; - wr_data = insn[22] ? {4{st_data[7:0]}} : st_data; - end - else if(insn[15:12] == 4'hF) - flush = 1'b1; - end - `DECODE_LDMSTM: begin - end - default: begin end - endcase - end + next_write_reg = write_reg; + next_write_num = write_num; + next_write_data = write_data; + next_outbubble = inbubble; + next_regs = regs; + cp_req = 1'b0; + cp_rnw = 1'bx; + cp_write = 32'hxxxxxxxx; + offset = prev_offset; + next_outcpsr = lsm_state == 3'b010 ? outcpsr : cpsr; + lsrh_rddata = 32'hxxxxxxxx; + lsrh_rddata_s1 = 16'hxxxx; + lsrh_rddata_s2 = 8'hxx; + next_lsm_state = lsm_state; + next_lsr_state = lsr_state; + next_lsrh_state = lsrh_state; + next_swp_oldval = swp_oldval; + next_swp_state = swp_state; + cur_reg = prev_reg; - assign align_s1 = raddr[1] ? {rd_data[15:0], rd_data[31:16]} : rd_data; - assign align_s2 = raddr[0] ? {align_s1[7:0], align_s1[31:8]} : align_s1; - assign align_rddata = insn[22] ? {24'b0, align_s2[7:0]} : align_s2; + /* XXX shit not given about endianness */ + if (flush) + next_outbubble = 1'b1; + else casez(insn) + `DECODE_ALU_SWP: if(!inbubble) begin + outstall = rw_wait; + next_outbubble = rw_wait; + busaddr = {op0[31:2], 2'b0}; + data_size = insn[22] ? 3'b001 : 3'b100; + case(swp_state) + 2'b01: begin + rd_req = 1'b1; + outstall = 1'b1; + if(!rw_wait) begin + next_swp_state = 2'b10; + next_swp_oldval = rd_data; + end + end + 2'b10: begin + wr_req = 1'b1; + wr_data = insn[22] ? {4{op1[7:0]}} : op1; + next_write_reg = 1'b1; + next_write_num = insn[15:12]; + next_write_data = insn[22] ? {24'b0, swp_oldval[7:0]} : swp_oldval; + if(!rw_wait) + next_swp_state = 2'b01; + end + default: begin end + endcase + end + `DECODE_ALU_HDATA_REG, + `DECODE_ALU_HDATA_IMM: if(!inbubble) begin + next_outbubble = rw_wait; + outstall = rw_wait; + addr = insn[23] ? op0 + op1 : op0 - op1; /* up/down select */ + raddr = insn[24] ? op0 : addr; /* pre/post increment */ + busaddr = raddr; + /* rotate to correct position */ + case(insn[6:5]) + 2'b00: begin end /* swp */ + 2'b01: begin /* unsigned half */ + wr_data = {2{op2[15:0]}}; /* XXX need to store halfword */ + data_size = 3'b010; + lsrh_rddata = {16'b0, raddr[1] ? rd_data[31:16] : rd_data[15:0]}; + end + 2'b10: begin /* signed byte */ + wr_data = {4{op2[7:0]}}; + data_size = 3'b001; + lsrh_rddata_s1 = raddr[1] ? rd_data[31:16] : rd_data[15:0]; + lsrh_rddata_s2 = raddr[0] ? lsrh_rddata_s1[15:8] : lsrh_rddata_s1[7:0]; + lsrh_rddata = {{24{lsrh_rddata_s2[7]}}, lsrh_rddata_s2}; + end + 2'b11: begin /* signed half */ + wr_data = {2{op2[15:0]}}; + data_size = 3'b010; + lsrh_rddata = raddr[1] ? {{16{rd_data[31]}}, rd_data[31:16]} : {{16{rd_data[15]}}, rd_data[15:0]}; + end + endcase - always @(posedge clk) - begin - outpc <= pc; - outbubble <= rw_wait; - casez(insn) - `DECODE_LDRSTR_UNDEFINED: begin - writeback <= 1'b0; - regsel <= 4'hx; - regdata <= 32'hxxxxxxxx; - notdone <= 1'b0; + case(lsrh_state) + 2'b01: begin + rd_req = insn[20]; + wr_req = ~insn[20]; + next_write_num = insn[15:12]; + next_write_data = lsrh_rddata; + if(insn[20]) begin + next_write_reg = 1'b1; + end + if(insn[21] | !insn[24]) begin + outstall = 1'b1; + if(!rw_wait) + next_lsrh_state = 2'b10; + end + end + 2'b10: begin + next_write_reg = 1'b1; + next_write_num = insn[19:16]; + next_write_data = addr; + next_lsrh_state = 2'b10; + end + default: begin end + endcase + end + `DECODE_LDRSTR_UNDEFINED: begin end + `DECODE_LDRSTR: if(!inbubble) begin + next_outbubble = rw_wait; + outstall = rw_wait; + addr = insn[23] ? op0 + op1 : op0 - op1; /* up/down select */ + raddr = insn[24] ? addr : op0; /* pre/post increment */ + busaddr = raddr; + /* rotate to correct position */ + align_s1 = raddr[1] ? {rd_data[15:0], rd_data[31:16]} : rd_data; + align_s2 = raddr[0] ? {align_s1[7:0], align_s1[31:8]} : align_s1; + /* select byte or word */ + align_rddata = insn[22] ? {24'b0, align_s2[7:0]} : align_s2; + wr_data = insn[22] ? {4{op2[7:0]}} : op2; /* XXX need to actually store just a byte */ + data_size = insn[22] ? 3'b001 : 3'b100; + case(lsr_state) + 2'b01: begin + rd_req = insn[20]; + wr_req = ~insn[20]; + next_write_reg = 1'b1; + next_write_num = insn[15:12]; + if(insn[20]) begin + next_write_data = align_rddata; + end + if(insn[21] | !insn[24]) begin + outstall = 1'b1; + if(!rw_wait) + next_lsr_state = 2'b10; + end + end + 2'b10: begin + next_write_reg = 1'b1; + next_write_num = insn[19:16]; + next_write_data = addr; + next_lsr_state = 2'b01; + end + default: begin end + endcase end - `DECODE_LDRSTR: begin - if(insn[20] && !inc_next) begin /* load - delegate regfile write to writeback stage */ - if(insn[15:12] == 4'hF) begin - newpc <= align_rddata; + /* XXX ldm/stm incorrect in that stupid case where one of the listed regs is the base reg */ + `DECODE_LDMSTM: if(!inbubble) begin + outstall = rw_wait; + next_outbubble = rw_wait; + data_size = 3'b100; + case(lsm_state) + 3'b001: begin +// next_regs = insn[23] ? op1[15:0] : op1[0:15]; + /** verilator can suck my dick */ + next_regs = insn[23] ? op1[15:0] : {op1[0], op1[1], op1[2], op1[3], op1[4], op1[5], op1[6], op1[7], + op1[8], op1[9], op1[10], op1[11], op1[12], op1[13], op1[14], op1[15]}; + offset = 6'b0; + outstall = 1'b1; + next_lsm_state = 3'b010; + end + 3'b010: begin + rd_req = insn[20]; + wr_req = ~insn[20]; + casez(regs) + 16'b???????????????1: begin + cur_reg = 4'h0; + next_regs = {regs[15:1], 1'b0}; + end + 16'b??????????????10: begin + cur_reg = 4'h1; + next_regs = {regs[15:2], 2'b0}; + end + 16'b?????????????100: begin + cur_reg = 4'h2; + next_regs = {regs[15:3], 3'b0}; + end + 16'b????????????1000: begin + cur_reg = 4'h3; + next_regs = {regs[15:4], 4'b0}; + end + 16'b???????????10000: begin + cur_reg = 4'h4; + next_regs = {regs[15:5], 5'b0}; + end + 16'b??????????100000: begin + cur_reg = 4'h5; + next_regs = {regs[15:6], 6'b0}; + end + 16'b?????????1000000: begin + cur_reg = 4'h6; + next_regs = {regs[15:7], 7'b0}; + end + 16'b????????10000000: begin + cur_reg = 4'h7; + next_regs = {regs[15:8], 8'b0}; + end + 16'b???????100000000: begin + cur_reg = 4'h8; + next_regs = {regs[15:9], 9'b0}; + end + 16'b??????1000000000: begin + cur_reg = 4'h9; + next_regs = {regs[15:10], 10'b0}; + end + 16'b?????10000000000: begin + cur_reg = 4'hA; + next_regs = {regs[15:11], 11'b0}; + end + 16'b????100000000000: begin + cur_reg = 4'hB; + next_regs = {regs[15:12], 12'b0}; + end + 16'b???1000000000000: begin + cur_reg = 4'hC; + next_regs = {regs[15:13], 13'b0}; + end + 16'b??10000000000000: begin + cur_reg = 4'hD; + next_regs = {regs[15:14], 14'b0}; + end + 16'b?100000000000000: begin + cur_reg = 4'hE; + next_regs = {regs[15], 15'b0}; + end + 16'b1000000000000000: begin + cur_reg = 4'hF; + next_regs = 16'b0; + end + default: begin + cur_reg = 4'hx; + next_regs = 16'b0; + end + endcase + cur_reg = insn[23] ? 4'hF - cur_reg : cur_reg; + if(cur_reg == 4'hF && insn[22]) begin + next_outcpsr = spsr; + end + + if(rw_wait) begin + next_regs = regs; + cur_reg = prev_reg; + raddr = prev_raddr; end else begin - writeback <= 1'b1; - regsel <= insn[15:12]; - regdata <= align_rddata; - end - inc_next <= 1'b1; - end - else if(insn[21]) begin /* write back */ - writeback <= 1'b1; - regsel <= insn[19:16]; - regdata <= addr; - inc_next <= 1'b0; - end else begin - writeback <= 1'b0; - inc_next <= 1'b0; - regsel <= 4'hx; - regdata <= 32'hxxxxxxxx; - end - notdone <= rw_wait & insn[20] & insn[21]; + offset = prev_offset + 6'h4; + offset_sel = insn[24] ? offset : prev_offset; + raddr = insn[23] ? op0 + {26'b0, offset_sel} : op0 - {26'b0, offset_sel}; + if(insn[20]) begin + next_write_reg = 1'b1; + next_write_num = cur_reg; + next_write_data = rd_data; + end + end + + st_read = cur_reg; + wr_data = st_data; + busaddr = raddr; + + outstall = 1'b1; + + if(next_regs == 16'b0) begin + next_lsm_state = 3'b100; + end + end + 3'b100: begin + next_write_reg = 1'b1; + next_write_num = insn[19:16]; + next_write_data = insn[23] ? op0 + {26'b0, prev_offset} : op0 - {26'b0, prev_offset}; + next_lsm_state = 3'b001; + end + default: begin end + endcase end - `DECODE_LDMSTM: begin + `DECODE_LDCSTC: if(!inbubble) begin + $display("WARNING: Unimplemented LDCSTC"); end - default: begin - writeback <= 1'b0; - regsel <= 4'hx; - regdata <= 32'hxxxxxxxx; - notdone <= 1'b0; + `DECODE_CDP: if(!inbubble) begin + cp_req = 1; + if (cp_busy) begin + outstall = 1; + next_outbubble = 1; + end + if (!cp_ack) begin + /* XXX undefined instruction trap */ + $display("WARNING: Possible CDP undefined instruction"); + end end + `DECODE_MRCMCR: if(!inbubble) begin + cp_req = 1; + cp_rnw = insn[20] /* L */; + if (insn[20] == 0 /* store to coprocessor */) + cp_write = op0; + else begin + if (insn[15:12] != 4'hF /* Fuck you ARM */) begin + next_write_reg = 1'b1; + next_write_num = insn[15:12]; + next_write_data = cp_read; + end else + next_outcpsr = {cp_read[31:28], cpsr[27:0]}; + end + if (cp_busy) begin + outstall = 1; + next_outbubble = 1; + end + if (!cp_ack) begin + $display("WARNING: Possible MRCMCR undefined instruction: cp_ack %d, cp_busy %d",cp_ack, cp_busy); + end + $display("MRCMCR: ack %d, busy %d", cp_ack, cp_busy); + end + default: begin end endcase end - endmodule