add csrc

lab3/csrc/CMakeLists.txt

@@ -5,8 +5,8 @@ project(yatcpu-programs C CXX ASM)
 # Setting variables
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0 --target=riscv32-unknown-elf -march=rv32i -mabi=ilp32")
 set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} -O0 --target=riscv32-unknown-elf -march=rv32i -mabi=ilp32")
-set(C_PROGRAMS tetris hello fibonacci quicksort)
-set(ASM_PROGRAMS mmio sb hazard)
+set(C_PROGRAMS tetris hello fibonacci quicksort paging tetris_mmu)
+set(ASM_PROGRAMS mmio sb)
 set(LINKER_SCRIPT ${CMAKE_SOURCE_DIR}/link.lds)
 set(LINKER_FLAGS -T ${LINKER_SCRIPT}) 
 set(OBJCOPY_ARGS -O binary -j .text -j .data)
@@ -32,8 +32,8 @@ foreach(program IN LISTS ASM_PROGRAMS)
 	set_target_properties(${program} PROPERTIES LINK_DEPENDS ${LINKER_SCRIPT})
 endforeach()
 
-# Copy the .text section to .asmbin files
-foreach(program IN LISTS C_PROGRAMS ASM_PROGRAMS)
+# Copy the .text and .data section to .asmbin files
+foreach(program IN LISTS C_PROGRAMS ASM_PROGRAMS PROGRAMS)
 	add_custom_command(
 		TARGET ${program}
 		POST_BUILD

lab3/csrc/hazard.S

@@ -1,48 +0,0 @@
-# Copyright 2022 Canbin Huang
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-.globl _start
-_start:
-  csrr a0, cycle
-
-  addi t0, zero, 1
-  sub t1, zero, t0
-  and t2, t0, t1
-  sw t2, 4(zero)
-  j skip1
-  or t2, t0, t1
-  xor t2, t0, t1
-
-skip1:
-  addi t1, t2, 1
-  add t2, t1, t2
-  and t2, t1, t2
-  lw t2, 2(t2)
-  or t3, t1, t2
-  blt t2, t3, skip2
-  or t3, t0, t0
-  xor t3, t0, t1
-
-skip2:
-  addi t4, zero, 3
-  bne t3, t4, skip1
-  sw t3, 8(zero)
-  auipc t4, 0
-  jalr t4, 8(t4)
-  jalr t4, 4(t4)
-  csrr a1, cycle
-  sub ra, a1, a0
-
-loop:
-  j loop

lab3/csrc/init.S

@@ -15,7 +15,7 @@
 .section .text.init
 .globl _start
 _start:
-  li sp, 4096 # Initialize stack pointer
+  li sp, 0x10000000 # Initialize stack pointer
   call main   # Jump to main function
 loop:
   j loop      # Loop forever
@@ -26,6 +26,16 @@ enable_interrupt:
   li t0, 0x1888
   csrrw t1, mstatus, t0 # enable interrupt
   ret
+.globl enable_paging
+enable_paging:
+  li t0, 0x80000005 # ppn << 12 = 0x005000
+  csrw satp, t0
+  ret
+.globl get_mtval
+get_mtval:
+  csrr a0, mtval
+  ret
+
 .globl get_epc
 get_epc:
   csrr a0, mepc

lab3/csrc/link.lds

@@ -6,6 +6,7 @@ SECTIONS
   . = 0x00001000;
   .text : { *(.text.init) *(.text.startup) *(.text) }
   .data ALIGN(0x1000) : { *(.data*) *(.rodata*) *(.sdata*) }
+  . = 0x00100000;
   .bss : { *(.bss) }
   _end = .;
 }

lab3/csrc/mm.h

@@ -0,0 +1,43 @@
+// Copyright 2022 hrpccs
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+typedef unsigned int uint32;
+typedef uint32 pte_t;
+typedef uint32* pagetable_t;
+
+#define PGSIZE 4096 // bytes per page
+#define PGSHIFT 12  // bits of offset within a page
+
+#define PGROUNDUP(sz)  (((sz)+PGSIZE-1) & ~(PGSIZE-1))
+#define PGROUNDDOWN(a) (((a)) & ~(PGSIZE-1))
+
+#define PTE_V (1L << 0) // valid
+#define PTE_R (1L << 1)
+#define PTE_W (1L << 2)
+#define PTE_X (1L << 3)
+#define PTE_U (1L << 4) // 1 -> user can access
+
+// shift a physical address to the right place for a PTE.
+#define PA2PTE(pa) ((((uint32)pa) >> 12) << 10)
+
+#define PTE2PA(pte) (((pte) >> 10) << 12)
+
+#define PTE_FLAGS(pte) ((pte) & 0x3FF)
+
+// extract the two 10-bit page table indices from a virtual address.
+#define PXMASK          0x3FF // 10 bits
+#define PXSHIFT(level)  (PGSHIFT+(10*(level)))
+#define PX(level, va) ((((uint32) (va)) >> PXSHIFT(level)) & PXMASK)
+
+#define MAXVA (1L << (10 + 10 + 12))

lab3/csrc/mmio.h

@@ -21,3 +21,13 @@
 #define UART_BAUDRATE ((volatile unsigned int *) (UART_BASE + 4))
 #define UART_RECV ((volatile unsigned int *) (UART_BASE + 12))
 #define UART_SEND ((volatile unsigned int *) (UART_BASE + 16))
+//remap the mmio to reduce memory usage of page table
+#define VA_VRAM_BASE 0x00100000
+#define VA_VRAM ((volatile unsigned char *) VA_VRAM_BASE)
+#define VA_TIMER_BASE 0x00200000
+#define VA_TIMER_LIMIT ((volatile unsigned int *) (VA_TIMER_BASE + 4))
+#define VA_TIMER_ENABLED ((volatile unsigned int *) (VA_TIMER_BASE + 8))
+#define VA_UART_BASE 0x00300000
+#define VA_UART_BAUDRATE ((volatile unsigned int *) (VA_UART_BASE + 4))
+#define VA_UART_RECV ((volatile unsigned int *) (VA_UART_BASE + 12))
+#define VA_UART_SEND ((volatile unsigned int *) (VA_UART_BASE + 16))

lab3/csrc/paging.c

@@ -0,0 +1,191 @@
+// # Copyright 2022 hrpccs
+// #
+// # Licensed under the Apache License, Version 2.0 (the "License");
+// # you may not use this file except in compliance with the License.
+// # You may obtain a copy of the License at
+// #
+// #     http://www.apache.org/licenses/LICENSE-2.0
+// #
+// # Unless required by applicable law or agreed to in writing, software
+// # distributed under the License is distributed on an "AS IS" BASIS,
+// # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// # See the License for the specific language governing permissions and
+// # limitations under the License.
+
+#include "mm.h"
+#include "mmio.h"
+
+
+
+#define SCREEN_COLS 80
+#define SCREEN_ROWS 30
+#define INT_TIMER_LIMIT 50000000
+#define PAGEDIR_BASE 0x5000
+
+typedef unsigned int uint32;
+typedef uint32 pte_t;
+typedef uint32* pagetable_t;
+
+extern void enable_paging();
+extern void enable_interrupt();
+extern int get_mtval();
+
+int wk_mul(int a, int b) {
+  int r = 0;
+  for (; b; a <<= 1, b >>= 1)
+    if (b & 1)
+      r += a;
+  return r;
+}
+
+void memoryset(unsigned char *dest,unsigned char num, unsigned int size){
+    for(unsigned int i=0;i<size;i++){
+        dest[i]=num;
+    }
+}
+
+uint32 pm[8]; //板子上有32kb内存，八个页
+uint32 timercount=0;
+void (*putch_at)(int,int,unsigned char);
+
+void __putch_at(int x, int y, unsigned char ch) {
+	VRAM[wk_mul(y,SCREEN_COLS) + x] = ch;
+}
+
+void __vputch_at(int x, int y, unsigned char ch) {
+	VA_VRAM[wk_mul(y,SCREEN_COLS) + x] = ch;
+}
+
+int alloc(){
+    int index = 0;
+    int max = 8;
+    while(index < max){
+        if(pm[index] == 0){
+            pm[index] = 1;
+            break;
+        }
+        index++;
+    }
+    return index == max ? -1 : index;
+}
+
+void map(pagetable_t pgtbl,uint32 va,uint32 pa,int perm){
+    int t;
+    if((pgtbl[PX(1,va)] & PTE_V )!= PTE_V){ //前缀不存在
+        t=alloc(); //申请一个页给前缀页表
+        if(t>=0){
+            int* taddr = (int*)(t<<12);
+            for(int i=0;i<PGSIZE>>2;i++){
+                taddr[i]=0;
+            }
+            pgtbl[PX(1,va)] = PA2PTE(t<<12) | PTE_V;
+        }else{
+            while(1);
+            for(int i=0;i<14;i++){
+                putch_at(i,22,"out of memory!"[i]);
+            }
+            while(1);
+        }
+    }
+    pagetable_t n = (void*)PTE2PA(pgtbl[PX(1,va)]);
+    n[PX(0,va)] = PA2PTE(pa) | perm | PTE_V;
+}
+
+
+void kvminit(){
+    pagetable_t pgtbl = (void*)PAGEDIR_BASE;
+    // memoryset(pgtbl,0,PGSIZE); //后面需要读这个内存，所以先初始化
+    for(int i=0;i<PGSIZE>>2;i++){
+        pgtbl[i]=0;
+    }
+
+    pm[PAGEDIR_BASE >> 12] = 1;
+    pm[0]=1;
+    pm[1]=1;
+    pm[2]=1;
+    pm[3]=1;
+    pm[4]=1;
+    //create pte mmap for text
+    pgtbl[1023] =  PA2PTE(PAGEDIR_BASE) | PTE_R | PTE_W;
+    map(pgtbl,PAGEDIR_BASE,PAGEDIR_BASE,PTE_R | PTE_W);
+    map(pgtbl,0x0,0x0, PTE_W | PTE_R ); //kernel stack
+    map(pgtbl,0x1000,0x1000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,0x2000,0x2000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,0x3000,0x3000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,0x4000,0x4000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,VA_VRAM_BASE,VRAM_BASE, PTE_W | PTE_R ); //
+    map(pgtbl,VA_VRAM_BASE + PGSIZE,VRAM_BASE + PGSIZE, PTE_W | PTE_R);
+    map(pgtbl,VA_UART_BASE,UART_BASE, PTE_W | PTE_R ); //
+    map(pgtbl,VA_TIMER_BASE,TIMER_BASE, PTE_W | PTE_R ); //
+}
+
+void clear_screen() {
+	int *vram = ((int *) VRAM_BASE);
+	for (int i = 0; i < 600; ++i) vram[i] = 0x20202020;
+}
+
+void trap_handler(void *epc, unsigned int cause) {
+	if (cause == 10 || cause == 15 || cause == 13) {
+        for(int i=0;i<39;i++){
+            putch_at(i,4,"A not handled page fault caused by : 0x"[i]);
+        }
+        int mtval = get_mtval();
+        char ch;
+        for (int i = 0; i < 8; ++i) {
+            unsigned int mask = 0xF << (i * 4);
+            unsigned int num = (mtval & mask) >> (i * 4);
+            if(num >= 10){
+                ch = num - 10 + 'A';
+            }else{
+                ch = num + '0';
+            }
+		    putch_at(39+7-i,4,ch);
+	    }
+        while(1); //目前还没有处理page-fault，因为还没有建立完整的映射。
+	} else if(cause == 0x80000007){
+        for(int i=0;i<16;i++){
+            putch_at(i,3,"timer count : 0x"[i]);
+        }
+        char ch;
+        for (int i = 0; i < 8; ++i) {
+            unsigned int mask = 0xF << (i * 4);
+            unsigned int num = (timercount & mask) >> (i * 4);
+            if(num >= 10){
+                ch = num - 10 + 'A';
+            }else{
+                ch = num + '0';
+            }
+		    putch_at(16+7-i,3,ch);
+	    }
+        timercount += 1;
+
+    }
+}
+
+int main(){
+    putch_at = __putch_at;
+    for(int i=0;i<8;i++){
+        pm[i] = 0;
+    }
+    timercount = 0;
+    clear_screen();
+    for(int i=0;i<19;i++){
+        putch_at(i,0,"print before paging"[i]);
+    }
+    kvminit();
+    putch_at = __vputch_at;
+    enable_paging();
+    for(int i=0;i<18;i++){
+        putch_at(i,1,"print after paging"[i]);
+    }
+    enable_interrupt();
+    *VA_TIMER_ENABLED = 1;
+    *VA_TIMER_LIMIT = INT_TIMER_LIMIT;
+
+    while(1){
+        if(timercount == 0x20){
+            *(int*)0x11415 = 1130;
+        }
+    }
+    for(;;);
+}

lab3/csrc/say_goodbye.c

@@ -0,0 +1,44 @@
+
+void uart_send_char(char c)
+{
+  *((volatile unsigned int *) (0x40000010)) = c;
+  // *((volatile unsigned int *) (0x40000000)) = c;
+}
+
+
+void waste_some_time(int cycle) {
+  unsigned int a = 135;
+  while (cycle--) {
+    a++;
+  }
+}
+
+int main() {
+
+    // const char* s = "abcd";
+    const char* s = "Never gonna give you up~ Never gonna let you down~\n\
+    Never gonna run around and~ desert you~\n";
+
+    while (1) {
+      
+
+      // for (int i = 0; i < ; i++) {
+      //   uart_send_char(s[i]);
+      //   waste_some_time(100);
+      // }
+
+      const char *p = s;
+      while (*p != 0)
+      {
+        uart_send_char(*p);
+        p++;
+        waste_some_time(100);
+      }
+
+      waste_some_time(200);
+
+      break;  // print once, but pressing CPU reset can print again
+    }
+
+    return 0;
+}

lab3/csrc/tetris.c

@@ -395,7 +395,7 @@ void on_timer() {
 void trap_handler(void *epc, unsigned int cause) {
 	if (cause == 0x80000007) {
 		on_timer();
-	} else {
+	} else if (cause == 0x8000000B){
 		unsigned int ch = *UART_RECV;
 		*UART_SEND = ch;
 		on_input(ch);
@@ -409,7 +409,7 @@ void init() {
 		putch_at(0, r, '|');
 		putch_at(COLS << 1 | 1, r, '|');
 	}
-	for (int c = 0; c <= (2 << COLS | 1); ++c) {
+	for (int c = 0; c <= (COLS << 1 | 1); ++c) {
 		putch_at(c, ROWS, '-');
 	}
 	int c = 8;
@@ -455,6 +455,9 @@ int main() {
 	init();
 #else
 	board = (unsigned char *) 16384;
+	for (int i = 0; i < 16384; i += 4) {
+		*((int*) (board + i)) = 0;
+	}
 	clear_screen();
 	init();
 	*((unsigned int *) 4) = 0xDEADBEEF;

lab3/csrc/tetris_mmu.c

@@ -0,0 +1,568 @@
+// Copyright 2021 Howard Lau
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifdef DEBUG
+#include <stdio.h>
+#endif
+
+#include "mmio.h"
+#include "mm.h"
+
+#define FALL_TIMER_LIMIT 50000000
+#define ROWS 22
+#define COLS 10
+#define OFFSET_X 28
+#define OFFSET_Y 3
+#define SCREEN_COLS 80
+#define SCREEN_ROWS 30
+
+
+struct block {
+	unsigned int shape[3];
+	unsigned int xywh;
+};
+
+struct block current;
+
+unsigned int score;
+
+unsigned char *board;
+
+
+
+int pm[8]; //板子上有32kb内存，八个页
+int timercount=0;
+// void (*putch_at)(int,int,unsigned char);
+#define PAGEDIR_BASE 0x5000
+
+#ifdef DEBUG
+unsigned char screen[SCREEN_COLS * SCREEN_ROWS];
+#endif
+
+int wk_mul(int a, int b) {
+  int r = 0;
+  for (; b; a <<= 1, b >>= 1)
+    if (b & 1)
+      r += a;
+  return r;
+}
+
+unsigned int make_xywh(unsigned int x, unsigned int y, unsigned int w, unsigned int h) {
+	return (x << 12) | (y << 4) | (w << 2) | h;
+}
+
+void init_block(struct block *block, int type, int x, int y) {
+	int w = 0; int h = 0;
+	block->shape[0] = block->shape[1] = block->shape[2] = 0;
+	switch(type) {
+	case 0: // I
+		block->shape[0] = 0xF;
+		w = 3; h = 0;
+	break;
+	case 1: // O
+		block->shape[0] = 0x3;
+		block->shape[1] = 0x3;
+		w = 1; h = 1;
+	break;
+	case 2: // J
+		block->shape[0] = 0x4;
+		block->shape[1] = 0x7;
+		w = 2; h = 1;
+		break;
+	case 3: // T
+		block->shape[0] = 0x2;
+		block->shape[1] = 0x7;
+		w = 2; h = 1;
+		break;
+	case 4: // L
+		block->shape[0] = 0x1;
+		block->shape[1] = 0x7;
+		w = 2; h = 1;
+		break;
+	case 5: // Z
+		block->shape[0] = 0x6;
+		block->shape[1] = 0x3;
+		w = 2; h = 1;
+		break;
+	case 6: // S
+		block->shape[0] = 0x3;
+		block->shape[1] = 0x6;
+		w = 2; h = 1;
+		break;
+	}
+	block->xywh = make_xywh(x, y, w, h);
+}
+
+unsigned int get_shape(struct block *block, unsigned int r, unsigned int c) {
+	return (block->shape[r] & (1 << c)) >> c;
+}
+
+unsigned int check_bounds(struct block *block) {
+	unsigned int xywh = block->xywh;
+	unsigned int h = xywh & 0x3;
+	unsigned int w = (xywh & 0xC) >> 2;
+	unsigned int y = (xywh & 0xFF0) >> 4;
+	unsigned int x = (xywh & 0xF000) >> 12;
+	if (x < 0 || x + w >= COLS) return 0;
+	if (y < 0 || y + h >= ROWS) return 0;
+	return 1;
+}
+
+void copy_block(struct block *dst, struct block *src) {
+	dst->xywh = src->xywh;
+	dst->shape[0] = src->shape[0];
+	dst->shape[1] = src->shape[1];
+	dst->shape[2] = src->shape[2];
+}
+
+unsigned int check_collision(struct block *block) {	
+	unsigned int xywh = block->xywh;
+	unsigned int h = xywh & 0x3;
+	unsigned int w = (xywh & 0xC) >> 2;
+	unsigned int y = (xywh & 0xFF0) >> 4;
+	unsigned int x = (xywh & 0xF000) >> 12;
+	for (int r = 0; r <= h; ++r) {
+		for (int c = 0; c <= w; ++c) {
+                  if (get_shape(block, r, c) &&
+                      board[wk_mul(y + r, COLS) + x + c])
+                    return 0;
+                }
+	}
+	return 1;
+}
+
+void putch_at(int x, int y, unsigned char ch) {
+#ifdef DEBUG
+	screen[wk_mul(OFFSET_Y + y, SCREEN_COLS) + x + OFFSET_X] = ch;
+#else
+	VA_VRAM[wk_mul(OFFSET_Y + y, SCREEN_COLS) + x + OFFSET_X] = ch;
+#endif
+}
+
+
+void block_move(struct block *block, int dir) {
+	unsigned int xywh = block->xywh;
+	unsigned int h = xywh & 0x3;
+	unsigned int w = (xywh & 0xC) >> 2;
+	unsigned int y = (xywh & 0xFF0) >> 4;
+	unsigned int x = (xywh & 0xF000) >> 12;
+	switch(dir) {
+	case 0: // Left
+		x--;
+		break;
+	case 1: // Right
+		x++;
+		break;
+	case 2: // Down
+		y++;
+		break;
+	default:
+		break;
+	}
+	block->xywh = (x << 12) | (y << 4) | (w << 2) | h;
+}
+
+unsigned int move(struct block *block, int dir) {
+	struct block moved;
+	copy_block(&moved, block);
+	block_move(&moved, dir);
+	if (check_bounds(&moved) && check_collision(&moved)) {
+		copy_block(block, &moved);
+		return 1;
+	}
+	return 0;
+}
+
+void block_rotate(struct block *block, unsigned int clock) {
+	unsigned int xywh = block->xywh;
+	unsigned int h = xywh & 0x3;
+	unsigned int w = (xywh & 0xC) >> 2;
+	unsigned int y = (xywh & 0xFF0) >> 4;
+	unsigned int x = (xywh & 0xF000) >> 12;
+	unsigned int xyhw = make_xywh(x, y, h, w);
+	unsigned int shape[3] = {0, 0, 0};
+	if (clock) {
+		for (int r = 0; r <= h; ++r) {
+			for (int c = 0; c <= w; ++c) {
+				shape[c] = shape[c] | (get_shape(block, r, c) << (h - r));
+			}
+		}
+		
+	} else {
+		for (int r = 0; r <= h; ++r) {
+			for (int c = 0; c <= w; ++c) {
+				shape[w - c] = shape[w - c] | (get_shape(block, r, c) << r);
+			}
+		}
+	}
+	block->shape[0] = shape[0];
+	block->shape[1] = shape[1];
+	block->shape[2] = shape[2];
+	block->xywh = xyhw;
+}
+
+
+void rotate(struct block *block, int clock) {
+	struct block rotated;
+	copy_block(&rotated, block);
+	block_rotate(&rotated, clock);
+	if (check_bounds(&rotated) && check_collision(&rotated)) {
+		copy_block(block, &rotated);
+		return;
+	}
+	unsigned int xywh = rotated.xywh;
+	unsigned int h = xywh & 0x3;
+	unsigned int w = (xywh & 0xc) >> 2;
+	unsigned int y = (xywh & 0xff0) >> 4;
+	unsigned int x = (xywh & 0xf000) >> 12;
+	if (x + w >= COLS) {
+		x = COLS - w - 1;
+	}
+	rotated.xywh = make_xywh(x, y, w, h);
+	if (check_bounds(&rotated) && check_collision(&rotated)) {
+		copy_block(block, &rotated);
+	}
+}
+
+void clear_board() {
+	for (int i = 0, s = wk_mul(ROWS, COLS); i < s; ++i) {
+		board[i] = 0;
+	}
+}
+
+void fix_block(struct block *block) {
+	unsigned int xywh = block->xywh;
+	unsigned int h = xywh & 0x3;
+	unsigned int w = (xywh & 0xc) >> 2;
+	unsigned int y = (xywh & 0xff0) >> 4;
+	unsigned int x = (xywh & 0xf000) >> 12;
+#ifdef DEBUG
+	printf("%d %d %d %d\n", x, y, w, h);
+#endif
+	for (int r = 0; r <= h; ++r) {
+		for (int c = 0; c <= w; ++c) {
+			if (get_shape(block, r, c)) {
+				board[wk_mul(y + r, COLS) + x + c] = 1;
+			}
+		}
+	}
+}
+
+void print_score() {
+	int c = 8;
+	putch_at(c++,  -2, 'S');
+	putch_at(c++, -2, 'C');
+	putch_at(c++, -2, 'O');
+	putch_at(c++, -2, 'R');
+	putch_at(c++, -2, 'E');
+	for (int i = 0; i < 5; ++i) {
+		unsigned int mask = 0xF << (i * 4);
+		unsigned int num = (score & mask) >> (i * 4);
+		putch_at(12 - i, -1, num + '0');
+	}
+}
+
+void draw_board() {
+	for (int r = 0; r < ROWS; ++r) {
+		for (int c = 0; c < COLS; ++c) {
+			if (board[wk_mul(r , COLS) + c] == 1) {
+				putch_at((c << 1) + 1, r, '[');
+				putch_at((c << 1) + 2, r, ']');
+			} else {
+				putch_at((c << 1) + 1, r, ' ');
+				putch_at((c << 1)+ 2, r, ' ');
+			}
+		}
+	}	
+	unsigned int xywh = current.xywh;
+	unsigned int h = xywh & 0x3;
+	unsigned int w = (xywh & 0xc) >> 2;
+	unsigned int y = (xywh & 0xff0) >> 4;
+	unsigned int x = (xywh & 0xf000) >> 12;
+	for (int r = 0; r <= h; ++r) {
+		for (int c = 0; c <= w; ++c) {
+			if (get_shape(&current, r, c)) {
+				putch_at(((c + x)  << 1) + 1, r + y, '[');
+				putch_at(((c + x)  << 1) + 2, r + y, ']');
+			}
+		}
+	}
+	print_score();
+}
+
+
+void add_score(unsigned int delta) {
+	score += delta;
+	for (unsigned int i = 0, carry = 0; i < 32; i += 4) {
+		unsigned int mask = 0xF << i;
+		unsigned int num = (score & mask) >> i;
+		num += carry;
+		if (num >= 10) {
+			carry = 1;
+			num -= 10;
+		} else {
+			carry = 0;
+		}
+		score &= ~(mask);
+		score |= (num << i);
+	}
+}
+
+void check_clear() {
+	unsigned int y = (current.xywh & 0xff0) >> 4;
+	unsigned int h = current.xywh & 0x3;
+	for (int r = y + h; r >= y; --r) {
+		unsigned int count = 0;
+		for (int c = 0; c < COLS; ++c) {
+			if (board[wk_mul(r , COLS) + c]) ++count;
+		}
+		if (count == COLS) {
+			add_score(1);
+			for (int nr = r - 1; nr > 0; --nr) {
+				for (int c = 0; c < COLS; ++c) {
+					board[wk_mul(nr + 1, COLS) + c] = board[wk_mul(nr, COLS) + c];
+				}
+			}
+			++r; ++y;
+		}
+	}
+}
+
+unsigned int rand() {
+	static unsigned int seed = 990315;
+	seed = (wk_mul(1103515245 , seed) + 12345) & 0x7FFFFFFF;
+	return seed;
+}
+
+unsigned int rand_type() {
+	unsigned int type = rand() & 0x7;
+	while (type == 7) {
+		type = rand() & 0x7;
+	}
+	return type;
+}
+
+void fall() {
+	if (move(&current, 2) == 0) {
+		fix_block(&current);
+		check_clear();
+		init_block(&current, rand_type(), 4, 0);
+	}
+}
+
+#ifdef DEBUG
+void print_screen() {
+	for (int r = 0; r < SCREEN_ROWS; ++r) {
+		for (int c = 0; c < SCREEN_COLS; ++c) {
+			printf("%c", screen[wk_mul(r, SCREEN_COLS) + c]);
+		}
+		printf("\n");
+	}
+	printf("\n");
+}
+#endif
+
+void on_input(unsigned int ch) {
+	switch (ch) {
+	case 's':
+		fall();
+		break;
+	case 'a':
+		move(&current, 0);
+		break;
+	case 'd':
+		move(&current, 1);
+		break;
+	case 'j':
+		rotate(&current, 0);
+		break;
+	case 'k':
+		rotate(&current, 1);
+		break;
+	}
+	draw_board();
+#ifdef DEBUG
+	print_screen();
+#endif
+}
+
+void on_timer() {
+	fall();
+	draw_board();
+}
+
+void trap_handler(void *epc, unsigned int cause) {
+	if (cause == 0x80000007) {
+		on_timer();
+	} else if (cause == 0x8000000B){
+		unsigned int ch = *VA_UART_RECV;
+		*VA_UART_SEND = ch;
+		on_input(ch);
+	}
+}
+
+void init() {
+	clear_board();
+	// Draw border
+	for (int r = 0; r < ROWS; ++r) {
+		putch_at(0, r, '|');
+		putch_at(COLS << 1 | 1, r, '|');
+	}
+	for (int c = 0; c <= (2 << COLS | 1); ++c) {
+		putch_at(c, ROWS, '-');
+	}
+	int c = 8; 
+	putch_at(c++, ROWS + 1, 'B');
+	putch_at(c++, ROWS + 1, 'e');
+	putch_at(c++, ROWS + 1, 'g');
+	putch_at(c++, ROWS + 1, 'i');
+	putch_at(c++, ROWS + 1, 'n');
+	putch_at(c++, ROWS + 1, ' ');
+	c = 6;
+	putch_at(c++, ROWS + 3, 'P');
+	putch_at(c++, ROWS + 3, 'a');
+	putch_at(c++, ROWS + 3, 'g');
+	putch_at(c++, ROWS + 3, 'i');
+	putch_at(c++, ROWS + 3, 'n');
+	putch_at(c++, ROWS + 3, 'g');
+	c++;
+	putch_at(c++, ROWS + 3, 'h');
+	putch_at(c++, ROWS + 3, 'r');
+	putch_at(c++, ROWS + 3, 'p');
+	c = 9;
+	putch_at(c++, ROWS + 4, '2');
+	putch_at(c++, ROWS + 4, '0');
+	putch_at(c++, ROWS + 4, '2');
+	putch_at(c++, ROWS + 4, '2');
+	init_block(&current, rand_type(), 4, 0);
+	score = 0;
+	draw_board();
+}
+
+int alloc(){
+    int index = 0;
+    int max = 8;
+    while(index < max){
+        if(pm[index] == 0){
+            pm[index] = 1;
+            break;
+        }
+        index++;
+    }
+    return index == max ? -1 : index;
+}
+
+int map(pagetable_t pgtbl,uint32 va,uint32 pa,int perm){
+    int t;
+    if((pgtbl[PX(1,va)] & PTE_V )!= PTE_V){ //前缀不存在
+        t=alloc(); //申请一个页给前缀页表
+        if(t>=0){
+            pgtbl[PX(1,va)] = PA2PTE(t<<12) | PTE_V;
+        }else{
+			return -1;
+		}
+    }
+    int* n = (void*)PTE2PA(pgtbl[PX(1,va)]);
+    n[PX(0,va)] = PA2PTE(pa) | perm | PTE_V;
+	return 0;
+}
+
+void kvminit(){
+	//init global valuable
+	for(int i=0;i<8;i++){
+        pm[i] = 0;
+    }
+    timercount = 0;
+
+    pagetable_t pgtbl = (void*)PAGEDIR_BASE;
+    // memoryset(pgtbl,0,PGSIZE); //后面需要读这个内存，所以先初始化
+    for(int i=0;i<PGSIZE>>2;i++){
+        pgtbl[i]=0;
+    }
+
+    pm[PAGEDIR_BASE >> 12] = 1;
+    pm[0]=1;
+    pm[1]=1;
+    pm[2]=1;
+    pm[3]=1;
+    pm[4]=1;
+    //create pte mmap for text
+    map(pgtbl,PAGEDIR_BASE,PAGEDIR_BASE,PTE_R | PTE_W);
+    map(pgtbl,0x0,0x0, PTE_W | PTE_R ); //kernel stack
+    map(pgtbl,0x1000,0x1000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,0x2000,0x2000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,0x3000,0x3000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,0x4000,0x4000, PTE_W | PTE_R | PTE_X ); //
+    map(pgtbl,VA_VRAM_BASE,VRAM_BASE, PTE_W | PTE_R ); //
+    map(pgtbl,VA_VRAM_BASE + PGSIZE,VRAM_BASE + PGSIZE, PTE_W | PTE_R);
+    map(pgtbl,VA_UART_BASE,UART_BASE, PTE_W | PTE_R ); //
+    map(pgtbl,VA_TIMER_BASE,TIMER_BASE, PTE_W | PTE_R ); //
+}
+
+void clear_screen() {
+	int *vram = ((int *) VA_VRAM_BASE);
+	for (int i = 0; i < 600; ++i) vram[i] = 0x20202020;
+}
+
+extern void enable_interrupt();
+extern void enable_paging();
+
+int main() {
+#ifdef DEBUG
+	unsigned char b[ROWS * COLS] = {0};
+	board = b;
+	for (int i = 0; i < SCREEN_ROWS * SCREEN_COLS; ++i) screen[i] = '%';
+	init();
+#else
+	kvminit();
+	enable_paging();
+	board = (unsigned char *) 16640; //0x4100
+	clear_screen();
+	init();
+	*((unsigned int *) 4) = 0xDEADBEEF;
+	enable_interrupt();
+	*VA_TIMER_ENABLED = 1;
+	*VA_TIMER_LIMIT = FALL_TIMER_LIMIT;
+	for (;;);
+#endif
+#ifdef DEBUG
+	on_input('a');
+	on_input('a');
+	on_input('s');
+	on_input('s');
+	on_input('s');
+	for (int i = 21; i >= 0; --i) {
+		on_timer();
+	}
+	on_input('d');
+	on_input('d');
+	on_input('d');
+	on_input('d');
+	for (int i = 21; i >= 0; --i) {
+		on_timer();
+	}
+	on_input('d');
+	on_input('d');
+	on_input('d');
+	on_input('d');
+	on_input('d');
+	for (int i = 21; i >= 0; --i) {
+		on_timer();
+		add_score(10);
+	}
+	print_score();
+	print_screen();
+	return 0;
+#endif
+}