12/8/2015\course\cpeg323-07Fs\Topic2b-323.ppt1 Topic 2b High-Level languages and System Software (Languages) Introduction to Computer Systems Engineering

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04/22/23 \course\cpeg323-07Fs\Topic2b-323.ppt 1

Topic 2b High-Level languages and

System Software(Languages)

Introduction to Computer Systems Engineering

(CPEG 323)


Reading List

• Slides: Topic2b

• K & R : C Programming Language

• JAVA in a Nutshell

Processors

Programs Written in High Level LanguagesHow Processors see the high level languages?The role of toolchainsConnections between ISA and high-level languagesConnections between ISA and Operating Systems


High Programming Languages

PortabilityAbstraction Penalty

Languages Categories Imperative (C) Functional (LISP) Logic (PROLOG) Object Oriented (Java) Scripting (Python)


Tim

elin

e o

f Pro

gra

mm

ing

Languages


Courtesy of Wikipedia. Original Author: Maximilian Dörrbecker

C versus Java

C K&R

Initial implementation of C 1978 Weakly type checking for arguments and implicit

integer return type. ANSI C / ISO C (C89 and C90)

De facto standard Function prototypes, void pointers, international

character sets, preprocessor enhancements (e.g. ## concatenation), prototypes, etc


C versus Java

C C99

Extension to several compilers Inline functions, new data types, variable length arrays (included in the GCC

compiler), variadic macros, etc

Java “Get the power and flexibility of C++, but in a smaller, simpler and

safer language” Not implicit pointers Implicit Garbage Collection Control statements Only controlled by primitive booleans Encapsulation is strictly enforced Concurrency Control Widening Cohercion only Applet versus standalone versus servlet versus Javaserver page versus

swing applications


C versus Java

C

ImperativeFunctionsLibraries are low levelManual Memory ManagementPointersLow Memory OverheadRelatively FastVariables initialize to garbage

Java

Object OrientedMethodsClass libraries of data structuresAutomatic Memory ManagementHigh Memory OverheadRelatively SlowVariables initialized to zero


C versus JavaHello, World in C Hello, World in Java


#include <stdio.h>

int main(int argc, char **argv)

{

/* This is a comment!!! */

printf("Hello, world!\n");

return 0;

}

public class HelloWorld {

public static void main(String[] args) {

System.out.println("Hello, world!");

}

}

C versus Java


C Code

Lexical AnalyzerSyntax

Analyzer

IR CG and Semantic Analyzer

CG

Optimizer

Symbol Table

Computer

Machine Code

Lexical AnalyzerSyntax

Analyzer

IR CG and Semantic Analyzer

Java Code

Java Byte Code (e.g. Java Source code .class files)

Java Virtual Machine

API Class filesJava

Platform

C Syntax

Very similar to Java but with a few differencesVariable Declarations must go at the beginning of the block (before they are used)A variable may be initialized in its declaration


Memory Storage for HLPL

Linear Storage of multi dimensional arrayRow Major order (C, C++, JAVA)


int A[4][5] | int[][] A = new int[4][5];

A(1,1) A(1,2) A(1,3) A(1,4) A(1,5) A(2,1) A(2,2) A(2,3) A(2,4) A(2,5)

A(3,1) A(3,2) A(3,3) A(3,4) A(3,5)

A(4,1) A(4,2) A(4,3) A(4,4) A(4,5)

A(1,1)A(1,2)A(1,3)A(1,4)A(1,5) A(2,1)A(2,2)A(2,3)A(2,4)A(2,5)A(3,1)A(3,2)A(3,3)A(3,4)A(3,5)A(4,1)A(4,2)A(4,3)A(4,4)A(4,5)

Memory

Memory Storage for HLPL

Column Major order (Fortran, MATLAB)


Memory

REAL A(4,5)

A(1,1) A(1,2) A(1,3) A(1,4) A(1,5)

A(2,1) A(2,2) A(2,3) A(2,4)

A(2,5)

A(3,1) A(3,2) A(3,3) A(3,4) A(3,5)

A(4,1) A(4,2) A(4,3) A(4,4) A(4,5)

A(1,1)A(2,1)A(3,1)A(4,1)A(1,2)A(2,2)A(3,2)A(4,2)A(1,3)A(2,3)A(3,3)A(4,3)A(1,4)A(2,4)A(3,4)A(4,4)A(1,5)A(2,5)A(3,5)A(4,5)

Assembly Language

Compiler Generates Assembly codeAssembly language Pseudo Instructions

li RX, Imm Load Immediate to register Translates to a pair of instructions (addiu / lui or

addiu / shori) if the immediate is greater than 16 bits la RX, VAR Load address of “VAR” into register

Translates according to the area in which VAR resides Global Area: one instruction addi RX, GP, OFFSET Another Area: Two Instructions lui RX, HI16(VAR);

addiu RX, RX, LOW16(VAR)


Load 32-bit Immediate


LUI R9, 0xAAAA

op 16-bit Imm

AAAAAAAA BBBBBBBB

op 16-bit ImmR9R9 R9

R9

ADDIU R9, R9, 0xBBBB

Load 32-bit Immediate


ADDI R9, R0, 0xAAAAop 16-bit Imm

AAAA

op 16-bit ImmR9

R9

R9

R9

SHORI R9,R9, 0xBBBB

BBBBAAAA

Shift 16 bits or

Assembly Language

Assembly language(cont.) Assembler directives

.file – source file name .text – start a text section .align – alignment requirement .data – data section .rdata – read-only data section .globl – an external name .ent – entry of a function .frame – information about the function frame .mask – integer registers used in this function .fmask – floating point registers used in this function .ascii – define a string of characters


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12/8/2015\course\cpeg323-07Fs\Topic2b-323.ppt1 Topic 2b High-Level languages and System Software (Languages) Introduction to Computer Systems Engineering