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,
next_outbubble = inbubble;
outstall = 1'b0;
next_regs = regs;
+ cp_req = 1'b0;
+ cp_rnw = 1'bx;
+ cp_write = 32'hxxxxxxxx;
offset = prev_offset;
next_outcpsr = lsm_state == 3'b010 ? out_cpsr : cpsr;
next_lsm_state = lsm_state;
next_swp_state = swp_state;
cur_reg = prev_reg;
+ /* XXX shit not given about endianness */
+ /* TODO ldrh/strh */
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;
+ `DECODE_ALU_SWP: 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
- default: begin end
- endcase
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
`DECODE_LDRSTR_UNDEFINED: begin end
- `DECODE_LDRSTR: begin
- 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};
-
+ `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 */
- 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 */
+ 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
+ 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
- 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
- 2'b10: begin
- next_write_reg = 1'b1;
- next_write_num = insn[19:16];
- next_write_data = addr;
- next_lsr_state = 2'b10;
+ outstall = 1'b1;
+ if(!rw_wait)
+ next_lsr_state = 2'b10;
end
- default: begin end
- endcase
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
+ /* 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;
case(lsm_state)
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
+ 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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