Files
risc-v-cpu/pipelined-cpu/srcs/rtl/cpu21_mmio.v
T
Alpha 47d2f22d07 fix(saolei): 修好鼠标事件链路三处 RTL bug —— 仿真里扫雷已能正常游玩
1) cpu21_pointer.v: sel 的位映射写错了(pend[2]->bit1, pend[1]->bit0, pend[0]->bit2),
   而输出读的是 sel[1]=-dx / sel[2]=+dy / sel[3]=-dy / sel[0]=+dx。
   后果:方向全乱(按下变左移、按右变下移),更致命的是清除逻辑
   press_pend_q <= pend_next & ~sel 清不掉被选中的那一位 -> ev_valid_o 永久为 1
   -> 鼠标中断线一直挂着 -> CPU 只收到一个上升沿、之后再无事件。改成一一对应。
2) cpu21_board_top.v: 鼠标中断与 LEVEL 软件中断的接线正好对调
   (mouse 接 irq_vec[0]=IRQ1=0x100=关卡入口, level 接 irq_vec[1]=IRQ2=0x200=鼠标)。
   后果:第一个鼠标事件把关卡叫起来画棋盘, 而鼠标 ISR 永不执行 -> FIFO 不弹空。
   按 linker.ld/mmio.h 约定交换;拨码开关 SW[2:0] 仍按位 OR 进来。
3) cpu21_mmio.v: 同步中断线注释。

仿真验证(tb_saolei + fb2png): 事件队列正常出入(h/t 同步增长)、光标方向正确、
点击 START 进关卡、关卡内点击揭开格子(fb_we +90)、数字场 1/2/3 与大片 BFS 展开均正确
2026-09-19 19:33:18 +08:00

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`timescale 1ns / 1ps
`default_nettype none
// -----------------------------------------------------------------------------
// MMIO:把外设寄存器映射到数据存储器地址空间。
//
// 地址映射(字节地址,都是"字对齐"译码:同一 32 位寄存器内的任意字节偏移都命中,
// 具体改哪几个字节由 wstrb_i 决定,与原来 LED 的语义一致):
//
// 0x0000_1000 LED 数据寄存器(**保持原有语义不变**,led_valid_o 拉高一拍)
// 0x0000_1004 七段数码管:8 位十六进制数(每 4 位一个数码管,低 4 位 = 最右)
// 0x0000_1100 + 4*k 鼠标寄存器组(见下)
// 0x0000_1140 + 4*k 显示控制器寄存器(见下)
// 0x0000_2000 - 0x27FF 显存窗口:40x30 格、每格 1 字节(只用到前 1200 字节)
//
// 鼠标寄存器(基址 0x1100):
// +0x00 STATUS RO [0] FIFO 非空 [5:1] 项数 [6] 中断使能 [7] FIFO 满
// +0x04 DATA RO [7:0] dx [15:8] dy [20:16] 按键(读无副作用)
// +0x08 ACK WO 写任意值 -> 弹出 FIFO 一项
// +0x0C CTRL RW [0] 中断使能(复位默认 1)
// +0x10 INPUT RO [15:0] 拨码开关 [20:16] 按键(原样)
// +0x14 TIME RO 自由运行计数器(随机种子)
// +0x18 FRAME RO VGA 帧计数
// +0x1C EVCNT RO 累计鼠标事件数
// +0x20 LEVEL RW [0] 写 1 -> 拉起 level_irq_o(软件中断,用作"关卡入口");
// 关卡程序返回前要写 0 清掉,否则下次没有上升沿
// +0x24 MAGIC RO 0xCAFE0002(自检用:读得到说明 MMIO 活着)
//
// 显示控制器寄存器(基址 0x1140):
// +0x00 CTRL RW [0] 光标可见 [6:4] 背景色(3 位调色板)
// +0x04 CURSOR RW [5:0] 列(0..39) [13:8] 行(0..29)
// +0x08 MAGIC RO 0xCAFE0001
//
// 显存本体不在本模块里:写操作通过 fb_* 端口直接送到板级顶层的双口 RAM(VGA 读
// 同一块 RAM),读操作把 fb_rdata_i 组合回读数据,保持"组合读"的时序不变。
//
// 两个中断源:
// mouse_irq_o = 中断使能 && 事件 FIFO 非空(顶层接到 irq_i[1] = IRQ2 = 入口 0x200)
// level_irq_o = LEVEL 寄存器(软件中断,顶层接到 irq_i[0] = IRQ1 = 入口 0x100 = 关卡)
//
// 以后要增加外设(UART、SD 卡等)时只需在这里扩展地址译码。
// -----------------------------------------------------------------------------
module cpu21_mmio #(
parameter [31:0] LED_ADDR = 32'h0000_1000,
parameter integer FB_WORDS = 300,
parameter integer FIFO_DEPTH = 16
) (
input wire clk,
input wire reset,
// MEM 级的访存请求(来自 EX/MEM 流水寄存器)
input wire mem_valid_i,
input wire mem_write_i,
input wire mem_read_i,
input wire [31:0] addr_i,
input wire [31:0] wdata_i,
input wire [ 3:0] wstrb_i,
// MMIO 读回
output wire [31:0] rdata_o,
output wire rdata_hit_o,
// LED 外设(原样保留)
output reg [31:0] led_data_o,
output reg led_valid_o,
// 七段数码管:8 位十六进制数
output reg [31:0] seg_data_o,
output reg seg_valid_o,
// 显存写端口(板级顶层的双口 RAM)
output wire fb_we_o,
output wire [ 9:0] fb_waddr_o,
output wire [31:0] fb_wdata_o,
output wire [ 3:0] fb_wstrb_o,
input wire [31:0] fb_rdata_i,
// 显示控制器寄存器(给 VGA 用)
output wire [31:0] disp_ctrl_o,
output wire [31:0] disp_cursor_o,
// 鼠标事件源(来自板级顶层:按键去抖 / PS/2 解析)
input wire mouse_ev_valid_i,
input wire [ 7:0] mouse_dx_i,
input wire [ 7:0] mouse_dy_i,
input wire [ 4:0] mouse_btn_i,
input wire [15:0] sw_i,
input wire frame_tick_i,
// 中断
output wire mouse_irq_o,
output wire level_irq_o
);
// ---------------------------------------------------------------------------
// 地址译码(都按"字"对齐:同一 32 位寄存器内的任意字节偏移都算命中)
// ---------------------------------------------------------------------------
localparam [31:0] SEG_ADDR = 32'h0000_1004;
localparam [31:0] MOUSE_BASE = 32'h0000_1100;
localparam [31:0] DISP_BASE = 32'h0000_1140;
localparam integer FIFO_AW = 4;
localparam [FIFO_AW:0] FIFO_FULL_V = FIFO_DEPTH[FIFO_AW:0];
wire sel_led = (addr_i[31:2] == LED_ADDR[31:2]);
wire sel_seg = (addr_i[31:2] == SEG_ADDR[31:2]);
wire sel_mouse = (addr_i[31:8] == MOUSE_BASE[31:8]) && (addr_i[7:6] == 2'b00);
wire sel_disp = (addr_i[31:8] == DISP_BASE[31:8]) && (addr_i[7:6] == 2'b01);
// 显存窗口 0x2000 - 0x27FF:bit13=1、bit12=0、bit11=0,高位全 0
// (原来写成 addr[12] && !addr[11],要求 bit12=1 —— 那是 0x1000-0x17FF,
// 于是 0x2000+ 的读写全都不命中、而鼠标/显示寄存器写反而落进了显存)
wire sel_fb = (addr_i[31:14] == 18'd0) && addr_i[13] && !addr_i[12] && !addr_i[11];
wire [3:0] midx = addr_i[5:2];
wire [3:0] didx = addr_i[5:2];
wire [9:0] fb_widx = addr_i[10:2];
wire fb_ok = (fb_widx < FB_WORDS);
wire led_wr = mem_valid_i && mem_write_i && sel_led;
wire led_rd = mem_valid_i && mem_read_i && sel_led;
wire seg_wr = mem_valid_i && mem_write_i && sel_seg;
wire seg_rd = mem_valid_i && mem_read_i && sel_seg;
wire mo_wr = mem_valid_i && mem_write_i && sel_mouse;
wire mo_rd = mem_valid_i && mem_read_i && sel_mouse;
wire dp_wr = mem_valid_i && mem_write_i && sel_disp;
wire dp_rd = mem_valid_i && mem_read_i && sel_disp;
wire fb_wr = mem_valid_i && mem_write_i && sel_fb && fb_ok;
wire fb_rd = mem_valid_i && mem_read_i && sel_fb && fb_ok;
assign fb_we_o = fb_wr;
assign fb_waddr_o = fb_widx;
assign fb_wdata_o = wdata_i;
assign fb_wstrb_o = wstrb_i;
assign rdata_hit_o = led_rd | seg_rd | mo_rd | dp_rd | fb_rd;
// 字节写合并:sw 改 4 字节、sb 只改 1 字节(与 RAM 的字节写语义一致)
function [31:0] merge_bytes;
input [31:0] new_v;
input [31:0] old_v;
input [ 3:0] strb;
begin
merge_bytes[7:0] = strb[0] ? new_v[7:0] : old_v[7:0];
merge_bytes[15:8] = strb[1] ? new_v[15:8] : old_v[15:8];
merge_bytes[23:16] = strb[2] ? new_v[23:16] : old_v[23:16];
merge_bytes[31:24] = strb[3] ? new_v[31:24] : old_v[31:24];
end
endfunction
// ---------------------------------------------------------------------------
// LED:保持原有语义(led_valid_o 只拉高一拍)
// ---------------------------------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
led_data_o <= 32'b0;
led_valid_o <= 1'b0;
end
else begin
led_valid_o <= 1'b0;
if (led_wr) begin
led_data_o <= merge_bytes(wdata_i, led_data_o, wstrb_i);
led_valid_o <= 1'b1;
end
end
end
// ---------------------------------------------------------------------------
// 七段数码管:8 位十六进制数(低 4 位 = 最右边那个数码管)
// ---------------------------------------------------------------------------
always @(posedge clk or posedge reset) begin
if (reset) begin
seg_data_o <= 32'b0;
seg_valid_o <= 1'b0;
end
else begin
seg_valid_o <= 1'b0;
if (seg_wr) begin
seg_data_o <= merge_bytes(wdata_i, seg_data_o, wstrb_i);
seg_valid_o <= 1'b1;
end
end
end
// ---------------------------------------------------------------------------
// 显示控制器寄存器(显存本体在板级顶层)
// ---------------------------------------------------------------------------
reg [31:0] disp_ctrl_q, disp_cursor_q;
assign disp_ctrl_o = disp_ctrl_q;
assign disp_cursor_o = disp_cursor_q;
// ---------------------------------------------------------------------------
// 鼠标:事件 FIFO + 寄存器 + 中断
// ---------------------------------------------------------------------------
reg [31:0] fifo [0:FIFO_DEPTH-1];
reg [FIFO_AW-1:0] wr_ptr_q, rd_ptr_q;
reg [FIFO_AW:0] cnt_q;
reg [31:0] mctrl_q, time_q, frame_q, evcnt_q;
reg level_q;
wire fifo_empty = (cnt_q == {FIFO_AW+1{1'b0}});
wire fifo_full = (cnt_q == FIFO_FULL_V);
wire [31:0] fifo_head = fifo[rd_ptr_q];
wire irq_en = mctrl_q[0];
assign mouse_irq_o = irq_en && !fifo_empty;
assign level_irq_o = level_q;
wire push = mouse_ev_valid_i && !fifo_full;
wire pop = mo_wr && (midx == 4'd2) && !fifo_empty;
always @(posedge clk or posedge reset) begin
if (reset) begin
mctrl_q <= 32'h0000_0001; // 鼠标中断默认打开
time_q <= 32'd0;
frame_q <= 32'd0;
evcnt_q <= 32'd0;
level_q <= 1'b0;
wr_ptr_q <= {FIFO_AW{1'b0}};
rd_ptr_q <= {FIFO_AW{1'b0}};
cnt_q <= {(FIFO_AW+1){1'b0}};
disp_ctrl_q <= 32'h0000_0001; // 光标可见,背景色 0
disp_cursor_q <= 32'h0000_0000;
end
else begin
time_q <= time_q + 32'd1;
if (frame_tick_i)
frame_q <= frame_q + 32'd1;
if (push) begin
fifo[wr_ptr_q] <= {11'b0, mouse_btn_i, mouse_dy_i, mouse_dx_i};
wr_ptr_q <= wr_ptr_q + 1'b1;
evcnt_q <= evcnt_q + 32'd1;
end
if (pop)
rd_ptr_q <= rd_ptr_q + 1'b1;
cnt_q <= cnt_q + (push ? 1'b1 : 1'b0) - (pop ? 1'b1 : 1'b0);
// 鼠标寄存器:CTRL(3) / LEVEL(8)
if (mo_wr) begin
case (midx)
4'd3:
mctrl_q <= merge_bytes(wdata_i, mctrl_q, wstrb_i);
4'd8:
level_q <= wdata_i[0];
default:
;
endcase
end
// 显示控制器:CTRL(0) / CURSOR(1)
if (dp_wr) begin
case (didx)
4'd0:
disp_ctrl_q <= merge_bytes(wdata_i, disp_ctrl_q, wstrb_i);
4'd1:
disp_cursor_q <= merge_bytes(wdata_i, disp_cursor_q, wstrb_i);
default:
;
endcase
end
end
end
// ---------------------------------------------------------------------------
// 读数据(组合,与"指令存储器组合读/数据存储器组合读"的时序一致)
// ---------------------------------------------------------------------------
reg [31:0] rdata_mux;
always @* begin
rdata_mux = 32'b0;
if (led_rd) begin
rdata_mux = led_data_o;
end
else if (seg_rd) begin
rdata_mux = seg_data_o;
end
else if (fb_rd) begin
rdata_mux = fb_rdata_i;
end
else if (mo_rd) begin
case (midx)
4'd0:
rdata_mux = {24'b0, fifo_full, irq_en, cnt_q[4:0], !fifo_empty};
4'd1:
rdata_mux = fifo_head;
4'd3:
rdata_mux = mctrl_q;
4'd4:
rdata_mux = {11'b0, mouse_btn_i, sw_i};
4'd5:
rdata_mux = time_q;
4'd6:
rdata_mux = frame_q;
4'd7:
rdata_mux = evcnt_q;
4'd8:
rdata_mux = {31'b0, level_q};
4'd9:
rdata_mux = 32'hCAFE_0002;
default:
rdata_mux = 32'b0;
endcase
end
else if (dp_rd) begin
case (didx)
4'd0:
rdata_mux = disp_ctrl_q;
4'd1:
rdata_mux = disp_cursor_q;
4'd2:
rdata_mux = 32'hCAFE_0001;
default:
rdata_mux = 32'b0;
endcase
end
end
assign rdata_o = rdata_mux;
endmodule
`default_nettype wire