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,
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 cpsrup,
+ 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,
+ output reg outcpsrup = 1'hx
+ );
+
+ reg [31:0] addr, raddr, prev_raddr, next_regdata, next_outcpsr;
+ reg next_outcpsrup;
+ reg [31:0] prevaddr;
+ reg [3:0] next_regsel, cur_reg, prev_reg;
+ reg next_writeback;
- /* stall */
- output outstall,
- output reg outbubble
-);
+ reg next_outbubble;
+ reg next_write_reg;
+ reg [3:0] next_write_num;
+ reg [31:0] next_write_data;
- reg [31:0] addr, raddr, next_regdata, next_newpc;
- reg [3:0] next_regsel;
- reg next_writeback, next_notdone, next_inc_next;
+ reg [3:0] lsr_state = 4'b0001, next_lsr_state;
reg [31:0] align_s1, align_s2, align_rddata;
- reg notdone = 1'b0;
- reg inc_next = 1'b0;
- assign outstall = rw_wait | notdone;
+ reg [2:0] lsrh_state = 3'b001, 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 [3:0] lsm_state = 4'b0001, 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;
+
+ reg do_rd_data_latch;
+ reg [31:0] rd_data_latch = 32'hxxxxxxxx;
+
+ 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;
+ if (!rw_wait)
+ prev_offset <= offset;
+ prev_raddr <= raddr;
+ outcpsr <= next_outcpsr;
+ outspsr <= spsr;
+ outcpsrup <= next_outcpsrup;
+ swp_state <= next_swp_state;
+ lsm_state <= next_lsm_state;
+ lsr_state <= next_lsr_state;
+ lsrh_state <= next_lsrh_state;
+ if (do_rd_data_latch)
+ rd_data_latch <= rd_data;
+ prevaddr <= addr;
+ end
+
+ reg delayedflush = 0;
+ always @(posedge clk)
+ if (flush && outstall /* halp! I can't do it now, maybe later? */)
+ delayedflush <= 1;
+ else if (!outstall /* anything has been handled this time around */)
+ delayedflush <= 0;
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;
- next_notdone = 1'b0;
- next_regsel = 4'hx;
- next_regdata = 32'hxxxxxxxx;
- next_inc_next = 1'b0;
- next_newpc = 32'hxxxxxxxx;
+ do_rd_data_latch = 0;
+ 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 == 4'b0010 ? outcpsr : cpsr;
+ next_outcpsrup = cpsrup;
+ 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;
+
+ /* XXX shit not given about endianness */
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];
+ `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
+ $display("SWP: read stage");
+ 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;
+ $display("SWP: write stage");
+ end
+ default: begin end
+ endcase
+ end
+ `DECODE_ALU_MULT: begin 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
+ case(lsrh_state)
+ 3'b001: 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 = 3'b010;
+ end
+ $display("ALU_LDRSTRH: rd_req %d, wr_req %d", rd_req, wr_req);
+ end
+ 3'b010: begin
+ next_outbubble = 1'b0;
+ next_write_reg = 1'b1;
+ next_write_num = insn[19:16];
+ next_write_data = addr;
+ next_lsrh_state = 3'b100;
+ end
+ 3'b100: begin
+ outstall = 0;
+ next_lsrh_state = 3'b001;
+ end
+ default: begin end
+ endcase
+
+ if ((lsrh_state == 3'b001) && flush) begin /* Reject it. */
+ outstall = 1'b0;
+ next_lsrh_state = 3'b001;
+ end
+ 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] ? {24'h0, {op2[7:0]}} : op2;
+ data_size = insn[22] ? 3'b001 : 3'b100;
+ case(lsr_state)
+ 4'b0001: begin
+ rd_req = insn[20] /* L */ || insn[22] /* B */;
+ wr_req = !insn[20] /* L */ && !insn[22]/* B */;
+ next_write_reg = insn[20] /* L */;
+ next_write_num = insn[15:12];
+ if(insn[20] /* L */) begin
+ next_write_data = insn[22] /* B */ ? {24'h0, align_rddata[7:0]} : align_rddata;
+ end
+ if (insn[22] /* B */ && !insn[20] /* L */) begin
+ do_rd_data_latch = 1;
+ outstall = 1'b1;
+ if (!rw_wait)
+ next_lsr_state = 4'b0010; /* XXX: One-hot, my ass. */
+ end else if(insn[21] /* W */ | !insn[24] /* P */) begin
+ outstall = 1'b1;
+ if(!rw_wait)
+ next_lsr_state = 4'b0100;
+ end
+ $display("LDRSTR: rd_req %d, wr_req %d, raddr %08x, wait %d", rd_req, wr_req, raddr, rw_wait);
+ end
+ 4'b0010: begin
+ $display("LDRSTR: Handling STRB");
+ outstall = 1;
+ rd_req = 0;
+ wr_req = 1;
+ next_write_reg = 0;
+ case (busaddr[1:0])
+ 2'b00: wr_data = {rd_data_latch[31:8], op2[7:0]};
+ 2'b01: wr_data = {rd_data_latch[31:16], op2[7:0], rd_data_latch[7:0]};
+ 2'b10: wr_data = {rd_data_latch[31:24], op2[7:0], rd_data_latch[15:0]};
+ 2'b11: wr_data = {op2[7:0], rd_data_latch[23:0]};
+ endcase
+ if(insn[21] /* W */ | !insn[24] /* P */) begin
+ if(!rw_wait)
+ next_lsr_state = 4'b0100;
+ end else if (!rw_wait)
+ next_lsr_state = 4'b1000;
+ end
+ 4'b0100: begin
+ outstall = 1;
+ rd_req = 0;
+ wr_req= 0;
+ next_outbubble = 0;
+ next_write_reg = 1'b1;
+ next_write_num = insn[19:16];
+ next_write_data = addr;
+ next_lsr_state = 4'b1000;
+ end
+ 4'b1000: begin
+ rd_req = 0;
+ wr_req= 0;
+ outstall = 0;
+ next_lsr_state = 4'b0001;
+ end
+ default: begin end
+ endcase
+
+ if ((lsr_state == 4'b0001) && flush) begin /* Reject it. */
+ outstall = 1'b0;
+ next_lsr_state = 4'b0001;
+ end
+ end
+ /* 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)
+ 4'b0001: begin
+// next_regs = insn[23] ? op1[15:0] : op1[0:15];
+ /** verilator can suck my dick */
+ $display("LDMSTM: Round 1: base register: %08x, reg list %b", op0, op1[15:0]);
+ next_regs = insn[23] /* U */ ? 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 = 4'b0010;
+ end
+ 4'b0010: 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] ? cur_reg : 4'hF - cur_reg;
+ if(cur_reg == 4'hF && insn[22]) begin
+ next_outcpsr = spsr;
+ next_outcpsrup = 1;
+ end
+
+ 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 = !rw_wait;
+ next_write_num = cur_reg;
+ next_write_data = rd_data;
+ end
+ if (rw_wait) begin
+ next_regs = regs;
+ cur_reg = prev_reg; /* whoops, do this one again */
+ end
+
+ st_read = cur_reg;
+ wr_data = (cur_reg == 4'hF) ? (pc + 12) : st_data;
+ busaddr = raddr;
+
+ $display("LDMSTM: Stage 2: Writing: regs %b, next_regs %b, reg %d, wr_data %08x, addr %08x", regs, next_regs, cur_reg, wr_data, busaddr);
- if(!insn[20]) begin
- st_read = insn[15:12];
- wr_data = insn[22] ? {4{st_data[7:0]}} : st_data;
+ outstall = 1'b1;
+
+ if(next_regs == 16'b0) begin
+ next_lsm_state = 4'b0100;
+ end
+ end
+ 4'b0100: begin
+ outstall = 1;
+ next_outbubble = 0;
+ next_write_reg = insn[21] /* writeback */;
+ next_write_num = insn[19:16];
+ next_write_data = insn[23] ? op0 + {26'b0, prev_offset} : op0 - {26'b0, prev_offset};
+ next_lsm_state = 4'b1000;
+ $display("LDMSTM: Stage 3: Writing back");
end
- else if(!inc_next) begin /* store */
- next_writeback = 1'b1;
- next_regsel = insn[15:12];
- next_regdata = align_rddata;
- next_inc_next = 1'b1;
+ 4'b1000: begin
+ outstall = 0;
+ next_lsm_state = 4'b0001;
end
- else if(insn[21]) begin
- next_writeback = 1'b1;
- next_regsel = insn[19:16];
- next_regdata = addr;
+ default: $stop;
+ endcase
+ if ((lsm_state == 4'b0001) && flush) begin /* Reject it. */
+ outstall = 1'b0;
+ next_lsm_state = 4'b0001;
end
- next_notdone = rw_wait & insn[20] & insn[21];
+ $display("LDMSTM: Decoded, bubble %d, insn %08x, lsm state %b -> %b, stall %d", inbubble, insn, lsm_state, next_lsm_state, outstall);
end
- `DECODE_LDMSTM: begin
+ `DECODE_LDCSTC: if(!inbubble) begin
+ $display("WARNING: Unimplemented LDCSTC");
+ end
+ `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 begin
+ next_outcpsr = {cp_read[31:28], cpsr[27:0]};
+ next_outcpsrup = 1;
+ end
+ 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
+
+ if ((flush || delayedflush) && !outstall)
+ next_outbubble = 1'b1;
end
-
-
- always @(posedge clk)
- begin
- outpc <= pc;
- outbubble <= rw_wait;
- writeback <= next_writeback;
- regsel <= next_regsel;
- regdata <= next_regdata;
- notdone <= next_notdone;
- newpc <= next_newpc;
- inc_next <= next_inc_next;
- end
-
endmodule
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