Memory: Split out bus address and data control logic. Split out LDM/STM register...
authorJoshua Wise <joshua@rebirth.joshuawise.com>
Sat, 31 Jan 2009 10:15:23 +0000 (05:15 -0500)
committerJoshua Wise <joshua@rebirth.joshuawise.com>
Sat, 31 Jan 2009 10:15:23 +0000 (05:15 -0500)
Memory.v

index 8cfd088..947a7ad 100644 (file)
--- a/Memory.v
+++ b/Memory.v
@@ -444,12 +444,11 @@ module Memory(
                endcase
        end
        
-       /* Bus control logic. */
+       /* Bus/address control logic. */
        always @(*)
        begin
                rd_req = 1'b0;
                wr_req = 1'b0;
-               wr_data = 32'hxxxxxxxx;
                offset = prev_offset;
                addr = prevaddr;
                raddr = 32'hxxxxxxxx;
@@ -463,10 +462,8 @@ module Memory(
                        case(swp_state)
                        `SWP_READING:
                                rd_req = 1'b1;
-                       `SWP_WRITING: begin
+                       `SWP_WRITING:
                                wr_req = 1'b1;
-                               wr_data = insn[22] ? {4{op1[7:0]}} : op1;
-                       end
                        default: begin end
                        endcase
                end
@@ -478,18 +475,12 @@ module Memory(
                        busaddr = raddr;
                        /* rotate to correct position */
                        case(insn[6:5])
-                       2'b01: begin /* unsigned half */
-                               wr_data = {2{op2[15:0]}}; /* XXX need to store halfword */
+                       2'b01: /* unsigned half */
                                data_size = 3'b010;
-                       end
-                       2'b10: begin /* signed byte */
-                               wr_data = {4{op2[7:0]}};
+                       2'b10: /* signed byte */
                                data_size = 3'b001;
-                       end
-                       2'b11: begin /* signed half */
-                               wr_data = {2{op2[15:0]}};
+                       2'b11: /* signed half */
                                data_size = 3'b010;
-                       end
                        default: begin
                                wr_data = 32'hxxxxxxxx;
                                data_size = 3'bxxx;
@@ -518,15 +509,8 @@ module Memory(
                                rd_req = insn[20] /* L */ || insn[22] /* B */;
                                wr_req = !insn[20] /* L */ && !insn[22]/* B */;
                        end
-                       `LSR_STRB_WR: begin
+                       `LSR_STRB_WR:
                                wr_req = 1;
-                               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
-                       end
                        `LSR_BASEWB: begin end
                        `LSR_WBFLUSH: begin end
                        default: begin end
@@ -540,7 +524,6 @@ module Memory(
                        `LSM_MEMIO: begin
                                rd_req = insn[20];
                                wr_req = ~insn[20];
-                               wr_data = (cur_reg == 4'hF) ? (pc + 12) : st_data;
                                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};
@@ -558,93 +541,61 @@ module Memory(
                endcase
        end
        
+       /* Bus data control logic. */
        always @(*)
        begin
-               st_read = 4'hx;
-               do_rd_data_latch = 0;
-               
-               next_outbubble = inbubble;
-               next_regs = regs;
+               wr_data = 32'hxxxxxxxx;
                
-               offset = prev_offset;
-               lsrh_rddata = 32'hxxxxxxxx;
-               lsrh_rddata_s1 = 16'hxxxx;
-               lsrh_rddata_s2 = 8'hxx;
-               next_swp_oldval = swp_oldval;
-               cur_reg = prev_reg;
-
-               /* XXX shit not given about endianness */
                casez(insn)
-               `DECODE_ALU_SWP: if(!inbubble) begin
-                       next_outbubble = rw_wait;
-                       case(swp_state)
-                       `SWP_READING:
-                               if(!rw_wait)
-                                       next_swp_oldval = rd_data;
-                       `SWP_WRITING: begin end
-                       default: begin end
-                       endcase
-               end
+               `DECODE_ALU_SWP: if(!inbubble)
+                       if (swp_state == `SWP_WRITING)
+                               wr_data = insn[22] ? {4{op1[7:0]}} : op1;
                `DECODE_ALU_MULT: begin end
                `DECODE_ALU_HDATA_REG,
-               `DECODE_ALU_HDATA_IMM: if(!inbubble) begin
-                       next_outbubble = rw_wait;
-                       
-                       /* rotate to correct position */
+               `DECODE_ALU_HDATA_IMM: if(!inbubble)
                        case(insn[6:5])
-                       2'b01: begin /* unsigned half */
-                               lsrh_rddata = {16'b0, raddr[1] ? rd_data[31:16] : rd_data[15:0]};
-                       end
-                       2'b10: begin /* signed byte */
-                               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 */
-                               lsrh_rddata = raddr[1] ? {{16{rd_data[31]}}, rd_data[31:16]} : {{16{rd_data[15]}}, rd_data[15:0]};
-                       end
-                       default: begin
-                               lsrh_rddata = 32'hxxxxxxxx;
-                       end
-                       endcase
-
-                       case(lsrh_state)
-                       `LSRH_MEMIO: begin end
-                       `LSRH_BASEWB:
-                               next_outbubble = 1'b0;
-                       `LSRH_WBFLUSH: begin end
+                       2'b01: /* unsigned half */
+                               wr_data = {2{op2[15:0]}}; /* XXX need to store halfword */
+                       2'b10: /* signed byte */
+                               wr_data = {4{op2[7:0]}};
+                       2'b11: /* signed half */
+                               wr_data = {2{op2[15:0]}};
                        default: begin end
                        endcase
-               end
                `DECODE_LDRSTR_UNDEFINED: begin end
                `DECODE_LDRSTR: if(!inbubble) begin
-                       next_outbubble = rw_wait;
-                       /* 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;
-                       case(lsr_state)
-                       `LSR_MEMIO:
-                               if (insn[22] /* B */ && !insn[20] /* L */)
-                                       do_rd_data_latch = 1;
-                       `LSR_STRB_WR: begin end
-                       `LSR_BASEWB:
-                               next_outbubble = 0;
-                       `LSR_WBFLUSH: begin end
-                       default: begin end
-                       endcase
+                       wr_data = insn[22] ? {24'h0, {op2[7:0]}} : op2;
+                       if (lsr_state == `LSR_STRB_WR)
+                               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
                end
-               /* XXX ldm/stm incorrect in that stupid case where one of the listed regs is the base reg */
+               `DECODE_LDMSTM: if (!inbubble)
+                       if (lsr_state == `LSM_MEMIO)
+                               wr_data = (cur_reg == 4'hF) ? (pc + 12) : st_data;
+               `DECODE_LDCSTC: begin end
+               `DECODE_CDP: begin end
+               `DECODE_MRCMCR: begin end
+               default: begin end
+               endcase
+       end
+       
+       /* LDM/STM register control logic. */
+       always @(*)
+       begin
+               offset = prev_offset;
+               cur_reg = prev_reg;
+               next_regs = regs;
+               
+               casez(insn)
                `DECODE_LDMSTM: if(!inbubble) begin
-                       next_outbubble = rw_wait;
                        case(lsm_state)
-                       `LSM_SETUP: begin
-//                             next_regs = insn[23] ? op1[15:0] : op1[0:15];
-                               /** verilator can suck my dick */
+                       `LSM_SETUP:
                                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]};
-                       end
                        `LSM_MEMIO: begin
                                casez(regs)
                                16'b???????????????1: begin
@@ -717,14 +668,102 @@ module Memory(
                                end
                                endcase
                                cur_reg = insn[23] ? cur_reg : 4'hF - cur_reg;
-
+                               
                                if (rw_wait) begin
                                        next_regs = regs;
                                        cur_reg = prev_reg;     /* whoops, do this one again */
                                end
-
+                               
                                st_read = cur_reg;
                        end
+                       `LSM_BASEWB: begin end
+                       `LSM_WBFLUSH: begin end
+                       default: begin end
+                       endcase
+               end
+               endcase
+       end
+       
+       always @(*)
+       begin
+               st_read = 4'hx;
+               do_rd_data_latch = 0;
+               
+               next_outbubble = inbubble;
+               
+               lsrh_rddata = 32'hxxxxxxxx;
+               lsrh_rddata_s1 = 16'hxxxx;
+               lsrh_rddata_s2 = 8'hxx;
+               next_swp_oldval = swp_oldval;
+
+               /* XXX shit not given about endianness */
+               casez(insn)
+               `DECODE_ALU_SWP: if(!inbubble) begin
+                       next_outbubble = rw_wait;
+                       case(swp_state)
+                       `SWP_READING:
+                               if(!rw_wait)
+                                       next_swp_oldval = rd_data;
+                       `SWP_WRITING: begin 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;
+                       
+                       /* rotate to correct position */
+                       case(insn[6:5])
+                       2'b01: begin /* unsigned half */
+                               lsrh_rddata = {16'b0, raddr[1] ? rd_data[31:16] : rd_data[15:0]};
+                       end
+                       2'b10: begin /* signed byte */
+                               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 */
+                               lsrh_rddata = raddr[1] ? {{16{rd_data[31]}}, rd_data[31:16]} : {{16{rd_data[15]}}, rd_data[15:0]};
+                       end
+                       default: begin
+                               lsrh_rddata = 32'hxxxxxxxx;
+                       end
+                       endcase
+
+                       case(lsrh_state)
+                       `LSRH_MEMIO: begin end
+                       `LSRH_BASEWB:
+                               next_outbubble = 1'b0;
+                       `LSRH_WBFLUSH: begin end
+                       default: begin end
+                       endcase
+               end
+               `DECODE_LDRSTR_UNDEFINED: begin end
+               `DECODE_LDRSTR: if(!inbubble) begin
+                       next_outbubble = rw_wait;
+                       /* 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;
+                       case(lsr_state)
+                       `LSR_MEMIO:
+                               if (insn[22] /* B */ && !insn[20] /* L */)
+                                       do_rd_data_latch = 1;
+                       `LSR_STRB_WR: begin end
+                       `LSR_BASEWB:
+                               next_outbubble = 0;
+                       `LSR_WBFLUSH: begin end
+                       default: begin end
+                       endcase
+               end
+               /* XXX ldm/stm incorrect in that stupid case where one of the listed regs is the base reg */
+               `DECODE_LDMSTM: if(!inbubble) begin
+                       next_outbubble = rw_wait;
+                       case(lsm_state)
+                       `LSM_SETUP: begin end
+                       `LSM_MEMIO: begin end
                        `LSM_BASEWB:
                                next_outbubble = 0;
                        `LSM_WBFLUSH: begin end
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