]> Joshua Wise's Git repositories - firearm.git/blobdiff - Memory.v
system, Writeback, Memory, Execute: Only update the CPSR when an update is specified...
[firearm.git] / Memory.v
index c709e83f9bddd130c691f6ae56b6fb53f896e7d4..7ca786e4c046aa8fc49b98f3dea20af937537911 100644 (file)
--- a/Memory.v
+++ b/Memory.v
@@ -36,6 +36,7 @@ module Memory(
        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,
@@ -49,10 +50,12 @@ module Memory(
        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 [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;
@@ -62,16 +65,16 @@ module Memory(
        reg [3:0] next_write_num;
        reg [31:0] next_write_data;
 
-       reg [1:0] lsr_state = 2'b01, next_lsr_state;
+       reg [2:0] lsr_state = 3'b001, next_lsr_state;
        reg [31:0] align_s1, align_s2, align_rddata;
 
-       reg [1:0] lsrh_state = 2'b01, next_lsrh_state;
+       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 [2:0] lsm_state = 3'b001, next_lsm_state;
+       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;
@@ -92,6 +95,7 @@ module Memory(
                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;
@@ -125,7 +129,8 @@ module Memory(
                cp_rnw = 1'bx;
                cp_write = 32'hxxxxxxxx;
                offset = prev_offset;
-               next_outcpsr = lsm_state == 3'b010 ? outcpsr : cpsr;
+               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;
@@ -197,7 +202,7 @@ module Memory(
                        endcase
 
                        case(lsrh_state)
-                       2'b01: begin
+                       3'b001: begin
                                rd_req = insn[20];
                                wr_req = ~insn[20];
                                next_write_num = insn[15:12];
@@ -208,18 +213,28 @@ module Memory(
                                if(insn[21] | !insn[24]) begin
                                        outstall = 1'b1;
                                        if(!rw_wait)
-                                               next_lsrh_state = 2'b10;
+                                               next_lsrh_state = 3'b010;
                                end
                                $display("ALU_LDRSTRH: rd_req %d, wr_req %d", rd_req, wr_req);
                        end
-                       2'b10: begin
+                       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 = 2'b10;
+                               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
@@ -236,7 +251,7 @@ module Memory(
                        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
+                       3'b001: begin
                                rd_req = insn[20] /* L */;
                                wr_req = ~insn[20] /* L */;
                                next_write_reg = insn[20] /* L */;
@@ -247,18 +262,29 @@ module Memory(
                                if(insn[21] /* W */ | !insn[24] /* P */) begin
                                        outstall = 1'b1;
                                        if(!rw_wait)
-                                               next_lsr_state = 2'b10;
+                                               next_lsr_state = 3'b010;
                                end
                                $display("LDRSTR: rd_req %d, wr_req %d, raddr %08x, wait %d", rd_req, wr_req, raddr, rw_wait);
                        end
-                       2'b10: begin
+                       3'b010: begin
+                               outstall = 1;
+                               next_outbubble = 0;
                                next_write_reg = 1'b1;
                                next_write_num = insn[19:16];
                                next_write_data = addr;
-                               next_lsr_state = 2'b01;
+                               next_lsr_state = 3'b100;
+                       end
+                       3'b100: begin
+                               outstall = 0;
+                               next_lsr_state = 3'b001;
                        end
                        default: begin end
                        endcase
+                       
+                       if ((lsr_state == 3'b001) && flush) begin       /* Reject it. */
+                               outstall = 1'b0;
+                               next_lsr_state = 3'b001;
+                       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
@@ -266,7 +292,7 @@ module Memory(
                        next_outbubble = rw_wait;
                        data_size = 3'b100;
                        case(lsm_state)
-                       3'b001: begin
+                       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]);
@@ -274,9 +300,9 @@ module Memory(
                                                                            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;
+                               next_lsm_state = 4'b0010;
                        end
-                       3'b010: begin
+                       4'b0010: begin
                                rd_req = insn[20];
                                wr_req = ~insn[20];
                                casez(regs)
@@ -352,6 +378,7 @@ module Memory(
                                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;
@@ -376,18 +403,28 @@ module Memory(
                                outstall = 1'b1;
 
                                if(next_regs == 16'b0) begin
-                                       next_lsm_state = 3'b100;
+                                       next_lsm_state = 4'b0100;
                                end
                        end
-                       3'b100: begin
+                       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 = 3'b001;
+                               next_lsm_state = 4'b1000;
                                $display("LDMSTM: Stage 3: Writing back");
                        end
+                       4'b1000: begin
+                               outstall = 0;
+                               next_lsm_state = 4'b0001;
+                       end
                        default: $stop;
                        endcase
+                       if ((lsm_state == 4'b0001) && flush) begin      /* Reject it. */
+                               outstall = 1'b0;
+                               next_lsm_state = 4'b0001;
+                       end
                        $display("LDMSTM: Decoded, bubble %d, insn %08x, lsm state %b -> %b, stall %d", inbubble, insn, lsm_state, next_lsm_state, outstall);
                end
                `DECODE_LDCSTC: if(!inbubble) begin
@@ -414,8 +451,10 @@ module Memory(
                                        next_write_reg = 1'b1;
                                        next_write_num = insn[15:12];
                                        next_write_data = cp_read;
-                               end else
+                               end else begin
                                        next_outcpsr = {cp_read[31:28], cpsr[27:0]};
+                                       next_outcpsrup = 1;
+                               end
                        end
                        if (cp_busy) begin
                                outstall = 1;
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