output reg [3:0] st_read,
input [31:0] st_data,
+ /* Coprocessor interface */
+ output reg cp_req,
+ input cp_ack,
+ input cp_busy,
+ output 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,
reg [31:0] addr, raddr, prev_raddr, next_regdata, next_outcpsr;
reg [3:0] next_regsel, cur_reg, prev_reg;
- reg next_writeback, next_notdone, next_inc_next;
+ reg next_writeback;
reg [31:0] align_s1, align_s2, align_rddata;
wire next_outbubble;
wire [3:0] next_write_num;
wire [31:0] next_write_data;
+ reg [1:0] lsr_state = 2'b01, next_lsr_state;
+
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
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;
out_cpsr <= next_outcpsr;
out_spsr <= spsr;
+ swp_state <= next_swp_state;
end
always @(*)
wr_data = 32'hxxxxxxxx;
busaddr = 32'hxxxxxxxx;
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 = started ? out_cpsr : cpsr;
+ next_outcpsr = lsm_state == 3'b010 ? out_cpsr : cpsr;
+ next_lsm_state = lsm_state;
+ next_lsr_state = lsr_state;
+ next_swp_oldval = swp_oldval;
+ next_swp_state = swp_state;
+ cur_reg = prev_reg;
casez(insn)
+ `DECODE_ALU_SWP: begin
+ if(!inbubble) begin
+ outstall = rw_wait;
+ next_outbubble = rw_wait;
+ busaddr = {op0[31:2], 2'b0};
+ 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 = op1;
+ next_write_reg = 1'b1;
+ next_write_num = insn[15:12];
+ next_write_data = swp_oldval;
+ if(!rw_wait)
+ next_swp_state = 2'b01;
+ end
+ default: begin end
+ endcase
+ end
+ end
`DECODE_LDRSTR_UNDEFINED: begin end
`DECODE_LDRSTR: begin
if (!inbubble) begin
next_outbubble = rw_wait;
- outstall = rw_wait | notdone;
-
+ 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};
- 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_reg = 1'b1;
- next_write_num = insn[15:12];
- next_write_data = align_rddata;
- next_inc_next = 1'b1;
+ case(lsr_state)
+ 2'b01: begin
+ rd_req = insn[20];
+ wr_req = ~insn[20];
+
+ 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
+ outstall = 1'b1;
+ if(!rw_wait)
+ next_lsr_state = 2'b10;
+ end
end
- else if(insn[21]) begin
+ 2'b10: begin
next_write_reg = 1'b1;
next_write_num = insn[19:16];
next_write_data = addr;
+ next_lsr_state = 2'b10;
end
- next_notdone = rw_wait & insn[20] & insn[21];
+ default: begin end
+ endcase
end
end
`DECODE_LDMSTM: begin
- rd_req = insn[20];
- wr_req = ~insn[20];
- if(!started) begin
+ outstall = rw_wait;
+ next_outbubble = rw_wait;
+ 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;
+ outstall = 1'b1;
+ next_lsm_state = 3'b010;
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;
- 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;
if(cur_reg == 4'hF && insn[22]) begin
next_outcpsr = spsr;
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 = 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;
-
- next_inc_next = next_regs == 16'b0;
- next_notdone = ~next_inc_next | rw_wait;
busaddr = {raddr[31:2], 2'b0};
+
+ outstall = 1'b1;
+
+ 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: begin
+ $display("WARNING: Unimplemented LDCSTC");
+ end
+ `DECODE_CDP: 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: begin
+ cp_req = 1;
+ cp_rnw = insn[20] /* L */;
+ if (insn[20] == 0 /* store to coprocessor */)
+ cp_write = op0;
+ else begin
+ next_write_reg = 1'b1;
+ next_write_num = insn[15:12];
+ next_write_data = cp_read;
+ end
+ if (cp_busy) begin
+ outstall = 1;
+ next_outbubble = 1;
+ end
+ if (!cp_ack) begin
+ $display("WARNING: Possible MRCMCR undefined instruction");
+ end
+ end
default: begin end
endcase
end
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