[EN] [application is in romanian]
Web-based app for detecting the rate of correct Branch Predictions inside a custom software CPU, all packed in a beautiful UI.
The cpuBP application is a didactic software program, and more precisely, an INTERPRETER that implements a processor (simulated software), and implicitly, by its nature, implements an assembly language that works in the structure of the built processor, to make jump predictions for testing and the study of the efficiency of the latter in improving the performance of processor architectures.
The application was built for teaching purposes, to serve future students in the laboratory rooms to study how to make predictions of jump instruction in the processor, but also to study their effectiveness, all using only this application.
This allows, before the actual jump predictions, which present the purpose of the present paper, the writing of code in the custom assembly language integrated in it's functionality, in a simpler and more intelligible manner.
The build custom simulated CPU inside the application features the following BRANCH PREDICTORS:
-Static NOT-TAKEN (always returns the response: not-taken. Tells the CPU that The jump will NOT be taken)
-Static TAKEN (always returns the response: not-taken. Tells the CPU that The jump will NOT be taken)
-Dynamic 1-BIT (works by the following given finite-state automata)
-Dynamic 2-BIT (works by the following given finite-state automata)
The data structures and components of the CPU are:
Data memory(64k locations)
General-purpose registers: 15 general registers(R0-R14)(8bit each)
Program Memory(supports up to 10.000 instructions)
FLAGS: 4 flags (Z,C,N,O)
PHP 5.5+
XAMPP - Apache(for local webserver) or hosted web-server is fine.
App will be started from index.php file (eg. http://localhost/cpuBP/index.php)
Please refer to Pages/help.html , which contains all the details of the language and the instructions .
cpuBP ASM instructions(help about them in Pages/help.html)(These are example of use, not proof of concept):
JNZ 0xE300
JNZ to_label_jnz #it is easier to create labels inside JUMP instructions
JPZ 0x0001
JPZ to_label_jpz
eticheta_label_1:
JMP 0x1111
JMP _to_label #label in jump
JNC 0x1000
JNC to_label_jnc
JPC 0x1001
JPC to_label_jpc
JNN 0x1002
JNN to_label_jnn
JPN 0x1003
JPN to_label_jpn
JNO 0x1004
JNO to_label_jno
JPO 0x1005
JPO to_label_jpo
_to_label:
STR R3, R4, R5
STR R6 , 0xff
LDR R7, R8, R9
LDR R10, 0x55
ADD R11, R12
ADD R13, 0xA
ADC R14, R0
SUB R0, R1
SUB R0, 0x6
SBC R1, R2
AND R0, R1
ORR R0,R1
XOR R0,R1
CMP R10,R11
INV R13
SHL R13
SHR R13
ROL R13
ROR R13
PSH R7
POP R7
CLZ
CLC
CLN
NOP
HALT
Interface explained:
Tests:
A.-Running the application using - compute array sum
B.-Running the application using - compute max Element of array
C.-Running the application using - BRANCH PREDICTION on quicksort ASM algorithm
The example result of bubble sort algorithm can be found in public/test_and_resources . Can be tried by yourself.