blockram: fix hack, memory: add ldrh/strh
[firearm.git] / Memory.v
index ff9f397..eeec5a3 100644 (file)
--- a/Memory.v
+++ b/Memory.v
@@ -50,9 +50,9 @@ module Memory(
        );
 
        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 [31:0] align_s1, align_s2, align_rddata;
 
        wire next_outbubble;    
        wire next_write_reg;
@@ -60,6 +60,12 @@ module Memory(
        wire [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 [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;
@@ -83,11 +89,15 @@ module Memory(
                out_cpsr <= next_outcpsr;
                out_spsr <= 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;
@@ -105,8 +115,10 @@ module Memory(
                cp_write = 32'hxxxxxxxx;
                offset = prev_offset;
                next_outcpsr = lsm_state == 3'b010 ? out_cpsr : cpsr;
+               lsrh_rddata = 32'hxxxxxxxx;
                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;
@@ -139,31 +151,79 @@ module Memory(
                        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 */
+                               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]}};
+                               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]}};
+                               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];
+                               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] ? op0 : addr; /* pre/post increment */
-                       busaddr = {raddr[31:2], 2'b0};
-                               /* rotate to correct position */
+                       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;
-                       if(!insn[20]) begin
-                               wr_data = insn[22] ? {4{op2[7:0]}} : op2; /* XXX need to actually store just a byte */
-                       end
+                       wr_data = insn[22] ? {4{op2[7:0]}} : op2; /* XXX need to actually store just a byte */
                        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_reg = 1'b1;
-                                       next_write_num = insn[15:12];
                                        next_write_data = align_rddata;
                                end
-                                       if(insn[21]) begin
+                               if(insn[21] | !insn[24]) begin
                                        outstall = 1'b1;
                                        if(!rw_wait)
                                                next_lsr_state = 2'b10;
@@ -288,7 +348,7 @@ module Memory(
 
                                st_read = cur_reg;
                                wr_data = st_data;
-                               busaddr = {raddr[31:2], 2'b0};
+                               busaddr = raddr;
 
                                outstall = 1'b1;
 
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