# Computer Architecture 2021 Fall Assignment3
> contrubuted by < oucs638 >
# Environment Setup
- Follow [Lab 3](https://hackmd.io/@sysprog/S1Udn1Xtt) step install [srv32](https://github.com/sysprog21/srv32).
- Follow TA's [setup tutorial](https://hackmd.io/@eecheng/B1fEgnQwF).
- Install gtkwave.
```powershell=
# Install gtkwave using apt-get on ubuntu 20.04
sudo apt-get update
sudo apt-get -y install gtkwave
```
# Start
## Requirement 1
- Create directory in `srv32/sw` and create my c code and `Makefile` (copy from the `Makefile` in other directory in `srv32/sw`).
```powershell=
# In srv32/sw/
mkdir tribonacci
cd tribonacci
# Put my code in assignment1
vim tribonacci.c
# Copy Makefile and modify "SRC" and "TARGET"
cp ../hello/Makefile ./
```
:::spoiler C code
```c=
#include <stdio.h>
int tribonacci(volatile int n)
{
int t0 = 0, t1 = 1, t2 = 1, t3 = 0;
if (n == 0)
return 0;
else if (n == 1 || n == 2)
return 1;
for (int i = 2; i < n; i++) {
t3 = t0 + t1 + t2;
t0 = t1;
t1 = t2;
t2 = t3;
}
return t3;
}
int main(void)
{
volatile int num = 10;
volatile int ans = tribonacci(num);
printf("The result is %d.\n", ans);
return 0;
}
```
:::
- Back to `srv32` and run `tribonacci`.
```powershell=
# In srv32
make all
make tribonacci
```
:::spoiler Running results
```powershell=
make[1]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw'
make -C common
make[2]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/common'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/common'
make[2]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/tribonacci'
riscv-none-embed-gcc -O3 -Wall -march=rv32im -mabi=ilp32 -nostartfiles -nostdlib -L../common -o tribonacci.elf tribonacci.c -lc -lm -lgcc -lsys -T ../common/default.ld
riscv-none-embed-objcopy -j .text -O binary tribonacci.elf imem.bin
riscv-none-embed-objcopy -j .data -O binary tribonacci.elf dmem.bin
riscv-none-embed-objcopy -O binary tribonacci.elf memory.bin
riscv-none-embed-objdump -d tribonacci.elf > tribonacci.dis
riscv-none-embed-readelf -a tribonacci.elf > tribonacci.symbol
make[2]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/tribonacci'
make[1]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw'
make[1]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sim'
The result of tribonacci(10) is 149.
Excuting 2847 instructions, 3689 cycles, 1.295 CPI
Program terminate
- ../rtl/../testbench/testbench.v:418: Verilog $finish
Simulation statistics
=====================
Simulation time : 0.094 s
Simulation cycles: 3700
Simulation speed : 0.0393617 MHz
make[1]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sim'
make[1]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/tools'
./rvsim --memsize 128 -l trace.log ../sw/tribonacci/tribonacci.elf
The result of tribonacci(10) is 149.
Excuting 2847 instructions, 3689 cycles, 1.296 CPI
Program terminate
Simulation statistics
=====================
Simulation time : 0.003 s
Simulation cycles: 3689
Simulation speed : 1.240 MHz
make[1]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/tools'
Compare the trace between RTL and ISS simulator
=== Simulation passed ===
```
:::
## Requirement 2
- Read the signals inside srv32 associated to PC, branch, instruction memory (I-MEM), data memory (D-MEM), and instruction internals.
## Requirement 3
- Remove the function and `volatile` to optimize.
- Create new directory in `srv32/sw` named `tribonacci_opt`.
- Put new C code in `tribonacci_opt` and back to `srv32/`, then run `make tribonacci_opt`.
:::spoiler New C code
```c=
#include <stdio.h>
int main(void)
{
int num = 10, ans = 0;
if (num == 1 || num == 2)
ans = 1;
else {
int t0 = 0, t1 = 1, t2 = 1;
for (int i = 2; i < num; i++) {
ans = t0 + t1 + t2;
t0 = t1;
t1 = t2;
t2 = ans;
}
}
printf("The result of tribonacci(%d) is %d.\n", num, ans);
return 0;
}
```
:::
:::spoiler Running result
```powershell=
make[1]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw'
make -C common
make[2]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/common'
make[2]: Nothing to be done for 'all'.
make[2]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/common'
make[2]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/tribonacci_opt'
riscv-none-embed-gcc -O3 -Wall -march=rv32im -mabi=ilp32 -nostartfiles -nostdlib -L../common -o tribonacci_opt.elf tribonacci_opt.c -lc -lm -lgcc -lsys -T ../common/default.ld
riscv-none-embed-objcopy -j .text -O binary tribonacci_opt.elf imem.bin
riscv-none-embed-objcopy -j .data -O binary tribonacci_opt.elf dmem.bin
riscv-none-embed-objcopy -O binary tribonacci_opt.elf memory.bin
riscv-none-embed-objdump -d tribonacci_opt.elf > tribonacci_opt.dis
riscv-none-embed-readelf -a tribonacci_opt.elf > tribonacci_opt.symbol
make[2]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw/tribonacci_opt'
make[1]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sw'
make[1]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sim'
The result of tribonacci(10) is 149.
Excuting 2776 instructions, 3604 cycles, 1.298 CPI
Program terminate
- ../rtl/../testbench/testbench.v:418: Verilog $finish
Simulation statistics
=====================
Simulation time : 0.068 s
Simulation cycles: 3615
Simulation speed : 0.0531618 MHz
make[1]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/sim'
make[1]: Entering directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/tools'
./rvsim --memsize 128 -l trace.log ../sw/tribonacci_opt/tribonacci_opt.elf
The result of tribonacci(10) is 149.
Excuting 2776 instructions, 3604 cycles, 1.298 CPI
Program terminate
Simulation statistics
=====================
Simulation time : 0.005 s
Simulation cycles: 3604
Simulation speed : 0.729 MHz
make[1]: Leaving directory '/home/oucs638/GitHub/CA_2021_FALL/Assignment3/srv32/tools'
Compare the trace between RTL and ISS simulator
=== Simulation passed ===
```
:::
- Differences before and after optimization
```powershell=
> Before optimization:
Excuting 2847 instructions, 3689 cycles, 1.296 CPI
Program terminate
Simulation statistics
=====================
Simulation time : 0.003 s
Simulation cycles: 3689
Simulation speed : 1.240 MHz
> After optimization:
Excuting 2776 instructions, 3604 cycles, 1.298 CPI
Program terminate
Simulation statistics
=====================
Simulation time : 0.005 s
Simulation cycles: 3604
Simulation speed : 0.729 MHz
```
# Reference
- [Assignment 3](https://hackmd.io/@sysprog/2021-arch-homework3)
- [Lab 3](https://hackmd.io/@sysprog/S1Udn1Xtt)
Sign in with Wallet
Connect another wallet