Memory: wire -> reg in some cases
[firearm.git] / Memory.v
index e04a804..241c50a 100644 (file)
--- a/Memory.v
+++ b/Memory.v
@@ -4,6 +4,8 @@ module Memory(
        input clk,
        input Nrst,
 
+       input flush,
+
        /* bus interface */
        output reg [31:0] busaddr,
        output reg rd_req,
@@ -11,11 +13,20 @@ 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,
@@ -23,6 +34,8 @@ module Memory(
        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,
@@ -34,25 +47,35 @@ module Memory(
        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] out_write_data = 32'hxxxxxxxx,
+       output reg [31:0] outspsr = 32'hxxxxxxxx,
+       output reg [31:0] outcpsr = 32'hxxxxxxxx
        );
 
-       reg [31:0] addr, raddr, prev_raddr, next_regdata;
+       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, next_notdone, next_inc_next;
+       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;
 
-       wire next_outbubble;    
-       wire next_write_reg;
-       wire [3:0] next_write_num;
-       wire [31:0] next_write_data;
+       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 started = 1'b0, next_started;
+       reg [2:0] lsm_state = 3'b001, next_lsm_state;
        reg [5:0] offset, prev_offset, offset_sel;
 
-       reg notdone = 1'b0;
-       reg inc_next = 1'b0;
+       reg [31:0] swp_oldval, next_swp_oldval;
+       reg [1:0] swp_state = 2'b01, next_swp_state;
 
        always @(posedge clk)
        begin
@@ -62,96 +85,188 @@ module Memory(
                out_write_reg <= next_write_reg;
                out_write_num <= next_write_num;
                out_write_data <= next_write_data;
-               notdone <= next_notdone;
-               inc_next <= next_inc_next;
                regs <= next_regs;
                prev_reg <= cur_reg;
-               started <= next_started;
                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;
-               next_notdone = 1'b0;
                next_write_reg = write_reg;
                next_write_num = write_num;
                next_write_data = write_data;
-               next_inc_next = 1'b0;
                next_outbubble = inbubble;
-               outstall = 1'b0;
-               next_regs = 16'b0;
-               next_started = started;
+               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;
 
-               casez(insn)
-               `DECODE_LDRSTR_UNDEFINED: begin end
-               `DECODE_LDRSTR: begin
-                       if (!inbubble) begin
-                               next_outbubble = rw_wait;
-                               outstall = rw_wait | notdone;
-                       
-                               addr = insn[23] ? op0 + op1 : op0 - op1; /* up/down select */
-                               raddr = insn[24] ? op0 : addr; /* pre/post increment */
-                               busaddr = {raddr[31:2], 2'b0};
+               /* 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
+
+                       case(lsrh_state)
+                       2'b01: begin
                                rd_req = insn[20];
                                wr_req = ~insn[20];
-                               
-                               /* 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;
-                               
-                               if(!insn[20]) begin
-                                       wr_data = insn[22] ? {4{op2[7:0]}} : op2; /* XXX need to actually store just a byte */
-                               end
-                               else if(!inc_next) begin
+                               next_write_num = insn[15:12];
+                               next_write_data = lsrh_rddata;
+                               if(insn[20]) begin
                                        next_write_reg = 1'b1;
-                                       next_write_num = insn[15:12];
+                               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] ? op0 : addr; /* 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;
-                                       next_inc_next = 1'b1;
                                end
-                               else if(insn[21]) begin
-                                       next_write_reg = 1'b1;
-                                       next_write_num = insn[19:16];
-                                       next_write_data = addr;
+                               if(insn[21] | !insn[24]) begin
+                                       outstall = 1'b1;
+                                       if(!rw_wait)
+                                               next_lsr_state = 2'b10;
                                end
-                               next_notdone = rw_wait & insn[20] & insn[21];
                        end
+                       2'b10: begin
+                               next_write_reg = 1'b1;
+                               next_write_num = insn[19:16];
+                               next_write_data = addr;
+                               next_lsr_state = 2'b10;
+                       end
+                       default: begin end
+                       endcase
                end
-               `DECODE_LDMSTM: begin
-                       rd_req = insn[20];
-                       wr_req = ~insn[20];
-                       if(!started) begin
+               /* 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;
-                               next_started = 1'b1;
-                       end
-                       else if(inc_next) begin
-                               if(insn[21]) 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};
-                               end
-                               next_started = 1'b0;
+                               outstall = 1'b1;
+                               next_lsm_state = 3'b010;
                        end
-                       else if(rw_wait) begin
-                               next_regs = regs;
-                               cur_reg = prev_reg;
-                               raddr = prev_raddr;
-                       end
-                       else begin
+                       3'b010: begin
+                               rd_req = insn[20];
+                               wr_req = ~insn[20];
                                casez(regs)
                                16'b???????????????1: begin
                                        cur_reg = 4'h0;
@@ -223,23 +338,80 @@ module Memory(
                                end
                                endcase
                                cur_reg = insn[23] ? 4'hF - cur_reg : cur_reg;
-                               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(cur_reg == 4'hF && insn[22]) begin
+                                       next_outcpsr = spsr;
+                               end
 
-                               if(insn[20]) begin
-                                       next_write_reg = 1'b1;
-                                       next_write_num = cur_reg;
-                                       next_write_data = rd_data;
+                               if(rw_wait) begin
+                                       next_regs = regs;
+                                       cur_reg = prev_reg;
+                                       raddr = prev_raddr;
+                               end
+                               else begin
+                                       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;
 
-                               next_inc_next = next_regs == 16'b0;
-                               next_notdone = ~next_inc_next | (rw_wait & insn[20] & insn[21]);
-                               busaddr = {raddr[31:2], 2'b0};
+                               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_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
+                                       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
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