跳转至

Lab4-3

在开始本实验之前，请备份 Lab4-1 与 Lab4-2 的所有工程，包括你使用的 IP Core。

你可以使用 git 保存之前的所有进度，并开新的分支来完成 Lab4-3。

在之前的实验中，我们完成了基本的指令，本节实验要在 Lab4-1 & Lab4-2 的基础之上拓展指令。

模块实现

在本节实验中，你需要实现以下指令：

  • R-Type: add, sub, and, or, xor, slt, srl, sll, sra, sltu
  • I-Type: addi, andi, ori, xori, slti, srli, slli, srai, slti, sltiu, lb, lh, lw, lbu, lhu, jalr
  • S-Type: sb, sh, sw
  • B-Type: beq, bne, blt, bge, bltu, bgeu
  • J-Type: jal
  • U-Type: lui, auipc

即 RISC-V 32I 中除了 ecall, ebreak 外的所有指令，黑体标出的指令为新添加的指令。在开始实验之前，请保证你理解了所有的指令含义与类型。

你可以在 venus 上使用以下代码来理解 sb, sh 的含义：

addi x11, x0, 0x421
lui x10, 0x33333
addi x10, x10, 0x333
sw x10, 48(zero)
sh x11, 49(zero)
add zero, zero, zero

addi x11, x0, 0x22
addi x10, x0, 0x20
lui x9, 0x33333
addi x9, x9, 0x333
sw x9,48(zero)
sb x11, 49(zero)
sb x10, 50(zero)
add zero, zero, zero

验收时，你需要提供自己绘制的 CPU 原理图，类似下图（下图仅为示意，并非本节实验的原理图）。建议在开始写代码之前绘制本图，梳理扩展指令时添加或修改的部件，明晰扩展指令的数据如何流动，控制信号应如何给。

你可以使用纸笔绘制（不推荐）但请保证验收时提供一张线条清晰较少涂改的原理图，也可以使用 Microsoft 的 Visio 或 PowerPoint、在线平台如 ProcessOn、 drawio 或平板软件绘制。

波形仿真

请修改上一节提供的 testbench，使之能够对指令扩展后的 SCPU 进行仿真验证。你可能需要将之前的 wea 信号从 1 位扩展为 4 位 /3 位 以支持扩展指令中的 unsigned, byte, half-word 的要求。

同时，你需要自行编写一段简单的代码对所有指令进行测试。

下板验证

验收代码 
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
auipc x26, 0x40
auipc x27, 0x80
srli x27, x27, 3
slli x27, x27, 3
srai x27, x27, 1
bne x27, x26, dummy
lui x26, 0x40000
lui x27, 0x80000
srai x27, x27, 1
beq x27, x26, dummy

# change your first digit in Studen ID to 3320'2233
addi x24, zero, 0x22
sb x24, 0x21(zero)
addi x24, zero, 0x20
sb x24, 0x22(zero)

# change your second digit in Studen ID to 2204'2122
addi x24, zero, 0x421
sh x24, 0x25(zero)

start:
addi x1, zero, -1 # x1=FFFFFFFF
lb x24, 0x18(zero) # x24=FFFFFFFF
bne x1, x24, dummy
lbu x24, 0x18(zero)# x24=000000FF
bge x1, x24, dummy
lh x24, 0x60(zero) # x24=FFFFF7E0
blt zero, x24, dummy
lhu x24, 0x60(zero) # x24=0000F7E0
blt x24, zero, dummy
xori x3, x1, 1 # x3=FFFFFFFE
add x3, x3, x3 # x3=FFFFFFFC
add x3, x3, x3 # x3=FFFFFFF8
add x3, x3, x3 # x3=FFFFFFF0
add x3, x3, x3 # x3=FFFFFFE0
add x3, x3, x3 # x3=FFFFFFC0
xor x20, x3, x1 # x20=0000003F
add x3, x3, x3 # x3=FFFFFF80
add x3, x3, x3 # x3=FFFFFF00
add x3, x3, x3 # x3=FFFFFE00
add x3, x3, x3 # x3=FFFFFC00
add x3, x3, x3 # x3=FFFFF800
add x3, x3, x3 # x3=FFFFF000
add x3, x3, x3 # x3=FFFFE000
add x3, x3, x3 # x3=FFFFC000
add x3, x3, x3 # x3=FFFF8000
add x3, x3, x3 # x3=FFFF0000
add x3, x3, x3 # x3=FFFE0000
add x3, x3, x3 # x3=FFFC0000
add x3, x3, x3 # x3=FFF80000
add x3, x3, x3 # x3=FFF00000
add x3, x3, x3 # x3=FFE00000
add x3, x3, x3 # x3=FFC00000
add x3, x3, x3 # x3=FF800000
add x3, x3, x3 # x3=FF000000
add x3, x3, x3 # x3=FE000000
add x3, x3, x3 # x3=FC000000
add x6, x3, x3 # x6=F8000000
add x3, x6, x6 # x3=F0000000
add x4, x3, x3 # x4=E0000000
add x13, x4, x4 # x13=C0000000
lui x8, 0x80000 # x8=80000000
ori x26, zero, 1 # x26=00000001
andi x26, x26, 0xff # x26=00000001
sra x30, x8, x26
srl x27, x8, x26

blt zero, zero, dummy
blt x26, zero, dummy
blt zero, x8, dummy

bge zero, x26, dummy
bge x8, zero, dummy

bne x27, x30, loop

dummy:
add zero, zero, zero # 4
add zero, zero, zero # 8
add zero, zero, zero # C
add zero, zero, zero # 10
add zero, zero, zero # 14
add zero, zero, zero # 18
add zero, zero, zero # 1C
jal zero, dummy

loop:
slt x2, x1, zero # x2=00000001 针对ALU32位有符号数减
sltu x25, x1, zero # x25=00000000
sltiu x29, x1, 0 # x29=00000000
slti x2, x1, 0 # x2=00000001 针对ALU32位有符号数减
add x14, x2, x2
add x14, x14, x14 # x14=4
sub x19, x14, x14 # x19=0
srli x19, x19, 1
addi x10, x19, -1
or x10, x10, zero
add x10, x10, x10 # x10=FFFFFFFE

loop1:
sw x6, 0x4(x3) # 计数器端口: F0000004, 送计数常数x6=F8000000
lw x5, 0x0(x3) # 读GPIO端口F0000000状态: {counter0_out,counter1_out,counter2_out,led_out[12:0], SW}
slli x5, x5, 2 # 左移2位将SW与LED对齐, 同时D1D0置00, 选择计数器通道0
sw x5, 0x0(x3) # x5输出到GPIO端口F0000000, 设置计数器通道counter_set=00端口
add x9, x9, x2 # x9=x9+1
sw x9, 0x0(x4) # x9送x4=E0000000七段码端口
lw x13, 0x14(zero) # 取存储器20单元预存数据至x13, 程序计数延时常数

loop2:
lw x5, 0x0(x3) # 读GPIO端口F0000000状态: {out0, out1, out2, D28-D20, LED7
add x5, x5, x5
add x5, x5, x5 # 左移2位将SW与LED对齐, 同时D1D0置00, 选择计数器通道0
sw x5, 0x0(x3) # x5输出到GPIO端口F0000000, 计数器通道counter_set=00端口不变
lw x5, 0x0(x3) # 再读GPIO端口F0000000状态
and x11, x5, x8 # 取最高位=out0, 屏蔽其余位送x11
add x13, x13, x2 # 程序计数延时
beq x13, zero, C_init # 程序计数x13=0, 转计数器初始化, 修改7段码显示: C_init

l_next: # 判断7段码显示模式：SW[4: 3]控制
lw x5, 0x0(x3) # 再读GPIO端口F0000000开关SW状态
add x18, x14, x14 # x14=4, x18=00000008
add x22, x18, x18 # x22=00000010
add x18, x18, x22 # x18=00000018(00011000)
and x11, x5, x18 # 取SW[4: 3]
beq x11, zero, L20 # SW[4: 3]=00, 7段显示"点"循环移位：L20, SW0=0
beq x11, x18, L21 # SW[4: 3]=11, 显示七段图形, L21, SW0=0
add x18, x14, x14 # x18=8
beq x11, x18, L22 # SW[4: 3]=01, 七段显示预置数字, L22, SW0=1
sw x9, 0x0(x4) # SW[4: 3]=10, 显示x9, SW0=1
bltu zero, x4, loop2

L20:
beq x10, x1, L4 # x10=ffffffff, 转移L4\\
bgeu x4, zero, L3

L4:
addi x10, zero, -1 # x10=ffffffff
add x10, x10, x10 # x10=fffffffe

L3:
sw x10, 0x0(x4) # SW[4: 3]=00, 7段显示点移位后显示
jal zero, loop2

L21:
lw x9, 0x60(x17) # SW[4: 3]=11, 从内存取预存七段图形
sw x9, 0x0(x4) # SW[4: 3]=11, 显示七段图形
addi x31, zero, 0x150
jalr zero, x31, 0x24 #jump to pc 0x174

L22:
lw x9, 0x20(x17) # SW[4: 3]=01, 从内存取预存数字
sw x9, 0x0(x4) # SW[4: 3]=01, 七段显示预置数字
blt x4, zero, loop2

C_init:
lw x13, 0x14(zero) # 取程序计数延时初始化常数
add x10, x10, x10 # x10=fffffffc, 7段图形点左移121 or x10, x10, x2 # x10末位置1, 对应右上角不显示
add x17, x17, x14 # x17=00000004, LED图形访存地址+4
and x17, x17, x20 # x17=000000XX, 屏蔽地址高位, 只取6位
add x9, x9, x2 # x9+1
beq x9, x1, L6 # 若x9=ffffffff, 重置x9=5
bge zero, zero, L7

L6:
add x9, zero, x14 # x9=4
add x9, x9, x2 # 重置x9=5

L7:
lw x5, 0x0(x3) # 读GPIO端口F0000000状态
add x11, x5, x5
slli x11, x11, 1 # 左移2位将SW与LED对齐, 同时D1D0置00, 选择计数器通道0
sw x11, 0x0(x3) # x5输出到GPIO端口F0000000, 计数器通道counter_set=00端口不变
sw x6, 0x4(x3) # 计数器端口: F0000004, 送计数常数x6=F8000000
bge zero, x4, l_next

memory_initialization_radix=16;
memory_initialization_vector=
00040D17, 00080D97, 003DDD93, 003D9D93, 401DDD93, 0FAD9C63, 
40000D37, 80000DB7, 401DDD93, 0FAD8463, 02200C13, 038000A3, 
02000C13, 03800123, 42100C13, 038012A3, FFF00093, 01800C03, 
0D809263, 01804C03, 0B80DE63, 06001C03, 0B804A63, 06005C03, 
0A0C4663, 0010C193, 003181B3, 003181B3, 003181B3, 003181B3, 
003181B3, 0011CA33, 003181B3, 003181B3, 003181B3, 003181B3, 
003181B3, 003181B3, 003181B3, 003181B3, 003181B3, 003181B3, 
003181B3, 003181B3, 003181B3, 003181B3, 003181B3, 003181B3, 
003181B3, 003181B3, 003181B3, 003181B3, 00318333, 006301B3, 
00318233, 004206B3, 80000437, 00106D13, 0FFD7D13, 41A45F33, 
01A45DB3, 00004C63, 000D4A63, 00804863, 01A05663, 00045463, 
03ED9263, 00000033, 00000033, 00000033, 00000033, 00000033, 
00000033, 00000033, FE5FF06F, 0000A133, 0000BCB3, 0000BE93, 
0000A113, 00210733, 00E70733, 40E709B3, 0019D993, FFF98513, 
00056533, 00A50533, 0061A223, 0001A283, 00229293, 0051A023, 
002484B3, 00922023, 01402683, 0001A283, 005282B3, 005282B3, 
0051A023, 0001A283, 0082F5B3, 002686B3, 06068263, 0001A283, 
00E70933, 01290B33, 01690933, 0122F5B3, 00058C63, 03258663, 
00E70933, 03258A63, 00922023, FA406CE3, 00150463, 00027663, 
FFF00513, 00A50533, 00A22023, FA1FF06F, 0608A483, 00922023, 
15000F93, 024F8067, 0208A483, 00922023, F80242E3, 01402683, 
00A50533, 00E888B3, 0148F8B3, 002484B3, 00148463, 00005663, 
00E004B3, 002484B3, 0001A283, 005285B3, 00159593, 00B1A023, 
0061A223, F64054E3;

memory_initialization_radix=16;
memory_initialization_vector=
f0000000, 000002AB, 80000000, 0000003F, 00000001, FFF70000, 0000FFFF, 80000000, 00000000, 11111111, 
22222222, 33333333, 44444444, 55555555, 66666666, 77777777, 88888888, 99999999, aaaaaaaa, bbbbbbbb, 
cccccccc, dddddddd, eeeeeeee, ffffffff, 557EF7E0, D7BDFBD9, D7DBFDB9, DFCFFCFB, DFCFBFFF, F7F3DFFF,
FFFFDF3D, FFFF9DB9, FFFFBCFB, DFCFFCFB, DFCFBFFF, D7DB9FFF, D7DBFDB9, D7BDFBD9, FFFF07E0, 007E0FFF,
03bdf020, 03def820, 08002300;

使用验收代码的预期表现与上一节基本相同，唯一变化是显示学号时，前两位 (32) 的显示将被改变。