cs2422 assembly language & system programming

CS2422 Assembly Language & System Programming

November 21, 2006

Today’s Topics (1/2)

• Assignment 3– Windows (graphics mode) programming.

– Linking to an assembly procedure.

– Setting up Visual C++ 2005 Express.

References

• Setting up Platform SDK: see the course webpage.

• Setting up Visual C++ 6.0 to compile and link assembly code with C or C++ code: included in the download file

• theForger’s Win32 API Tutorial http://winprog.org/tutorial. (Read at least the first two articles.)

http://winprog.org/tutorial

Demo

• The program creates a “mosaic” effect on your windows desktop.

• You need to set your display to use 24-bit or 32-bit colors.

• Using ML.exe /Zi option to enable debugging directly within your assembly code at Visual C++. (Already done for you if you use VC++ 2005 Express.)

Assembly Code to Be Written

Mosaic(img, resX, resY,

x, y, blockX, blockY)

Example Code

• Mosaic_C_version() in main.c shows the algorithm.

• To run the assembly code, remember to comment out:

#define MOSAIC_C_VERSION

• The Mosaic procedure in mosaic.asm gives an example of accessing parameters and local variables.

Img: a 2D Array• The img[] is conceptually 2D, but stored as if it

is a 1D array.• A pixel at location (x, y) is stored at

img[x + y * xRes] • Each pixel stores the Red, Green, Blue

components of a color in 4 bytes:struct { BYTE rgbBlue; BYTE rgbGreen; BYTE rgbRed; BYTE rgbReserved;} RGBQUAD;

Basic Structure of a Windows Program

• WinMain procedure.

• WinProc procedure.

• Section 11.2 explains the above in assembly. The C version in main.c might be easier to read.

• An excellent introductory material can be found at: http://winprog.org/tutorial. (Read at least the first two articles.)

http://winprog.org/tutorial

WinMain ProcedureEvery Windows application needs a startup procedure, usually named WinMain, which is responsible for the following tasks:

• Get a handle to the current program

• Load the program’s icon and mouse cursor

• Register the program’s main window class and identify the procedure that will process event messages for the window

• Create the main window

• Show and update the main window

• Begin a loop that receives and dispatches messages

WinProc Procedure• WinProc receives and processes all event messages

relating to a window– Some events are initiated by clicking and dragging the mouse,

pressing keyboard keys, and so on

• WinProc decodes each message, carries out application-oriented tasks related to the message

WinProc PROC,

hWnd:DWORD, ; handle to the window

localMsg:DWORD, ; message ID

wParam:DWORD, ; parameter 1 (varies)

lParam:DWORD ; parameter 2 (varies)

(Contents of wParam and lParam vary, depending on the message.)

What Will You Learn from This Assignment?

• Linking C and Assembly.

• The first step in Windows programming.

• Array processing.

• Implementation of nontrivial loops.

Today’s Topic (2/2)

• Chapter 1 of Beck’s “System Software” book.

Study Guide

• 1.1 Introduction

• 1.2 System Software and Machine Architecture

• 1.3 The Simplified Instructional Computer (SIC)– SIC Machine Architecture– SIC/XE Machine Architecture– SIC Programming Examples

Introduction

• Definition of System software– System software consists of a variety of

programs that support the operation of a computer

• E.g. of system software– Text editor, compiler, loader or linker,

debugger, macro processors, operating system, database management systems, software engineering tools, ….

System Software and Machine Architecture (1/2)

• One characteristic in which most system software differs from application software is machine dependency

• System programs are intended to support the operation and use of the computer itself, rather than any particular application.

System Software and Machine Architecture (2/2)

• Because most system software is machine-dependent, we must include real machines and real pieces of software in our study.

• Simplified Instructional Computer (SIC)– SIC is a hypothetical computer that has been

carefully designed to include the hardware features most often found on real machines, while avoiding unusual or irrelevant complexities

The Simplified Instructional Computer (SIC)

• Like many other products, SIC comes in two versions– The standard model – An XE version

• “extra equipments”, “extra expensive”

• The two versions has been designed to be upward compatible

SIC Machine Architecture (1/7)

• Memory– Memory consists of 8-bit bytes– Any 3 consecutive bytes form a word (24 bits)– Total of 32768 (215) bytes in the computer

memory

SIC Machine Architecture (2/7)• Registers

– Five registers– Each register is 24 bits in length

Mnemonic Number Special use

A 0 Accumulator

X 1 Index register

L 2 Linkage register

PC 8 Program counter

SW 9 Status word


• Data Formats– Integers are stored as 24-bit binary number– 2’s complement representation for negative

values– Characters are stored using 8-bit ASCII codes– No floating-point hardware on the standard

version of SIC


• Instruction Formats– Standard version of SIC

8 1 15

opcode x address

The flag bit x is used to indicate indexed-addressing mode


• Addressing Modes– There are two addressing modes available

• Indicated by x bit in the instruction

Mode Indication Target address calculation

Direct x=0 TA=address

Indexed x=1 TA=address+(X)

(X): the contents of register X

SIC Machine Architecture (6/7)• Instruction Set

– Load and store registers• LDA, LDX, STA, STX, etc.

– Integer arithmetic operations• ADD, SUB, MUL, DIV• All arithmetic operations involve register A and a word in memory,

with the result being left in A

– COMP– Conditional jump instructions

• JLT, JEQ, JGT

– Subroutine linkage• JSUB, RSUB

– See appendix A, Page 495


• Input and Output– Input and output are performed by transferring

1 byte at a time to or from the rightmost 8 bits of register A

• Test Device TD instruction

• Read Data (RD)

• Write Data (WD)

SIC Programming Examples (Fig 1.2a)

LDA FIVESTA ALPHALDCH CHARZSTCH C1...

ALPHA RESW 1 one-word variableFIVE WORD 5 one-word constantCHARZ BYTE C’Z’ one-byte constantC1 RESB 1 one-byte variable

SIC Programming Example (Fig 1.3a)

LDA ALPHAADD INCRSUB ONESTA BETALDA GAMMAADD INCRSUB ONESTA DELTA......

ONE WORD 1 one-word constantALPHA RESW 1 one-word variablesBETA RESW 1GAMMA RESW 1DELTA RESW 1INCR RESW 1


LDX ZERO initialize index register to 0MOVECH LDCH STR1,X load char from STR1 to reg A

STCH STR2,XTIX ELEVEN add 1 to index, compare to 11JLT MOVECH loop if “less than”...

STR1 BYTE C’TEST STRING’STR2 RESB 11ZERO WORD 0ELEVEN WORD 11


LDA ZERO initialize index value to 0STA INDEX

ADDLP LDX INDEX load index value to reg XLDA ALPHA,X load word from ALPHA into reg AADD BETA,XSTA GAMMA,X store the result in a word in GAMMALDA INDEXADD THREE add 3 to index valueSTA INDEXCOMP K300 compare new index value to 300JLT ADDLP loop if less than 300......

INDEX RESW 1ALPHA RESW 100 array variables—100 words eachBETA RESW 100GAMMA RESW 100ZERO WORD 0 one-word constantsTHREE WORD 3K300 WORD 300

SIC Programming Example (Fig 1.6)INLOOP TD INDEV test input device

JEQ INLOOP loop until device is readyRD INDEV read one byte into register ASTCH DATA..

OUTLP TD OUTDEV test output deviceJEQ OUTLP loop until device is readyLDCH DATAWD OUTDEV write one byte to output device..

INDEV BYTE X’F1’ input device numberOUTDEV BYTE X’05’ output device numberDATA RESB 1

SIC/XE Machine Architecture (1/13)

• Memory– Maximum memory available on a SIC/XE

system is 1 megabyte (220 bytes)


• Registers– Additional registers are provided by SIC/XE

Mnemonic Number Special use

B 3 Base register

S 4 General working register

T 5 General working register

F 6 Floating-point accumulator (48 bits)


• There is a 48-bit floating-point data type

1 11 36

s exponent fraction

F*2(e-1024)

SIC/XE Machine Architecture (4/13)• Instruction Formats

8

op

8 4 4

op r1 r2

Format 1 (1 byte)

Format 2 (2 bytes)

Formats 1 and 2 are instructions that do not reference memory at all

6 1 1 1 1 1 1 12

op n i x b p e dispFormat 3 (3 bytes)

6 1 1 1 1 1 1 20

op n i x b p e addressFormat 4 (4 bytes)


• Addressing modes– Base relative (n=1, i=1, b=1, p=0)– Program-counter relative (n=1, i=1, b=0, p=1)– Direct (n=1, i=1, b=0, p=0)– Immediate (n=0, i=1, x=0)– Indirect (n=1, i=0, x=0)– Indexing (both n & i = 0 or 1, x=1)– Extended (e=1)


• Base Relative Addressing Mode

n i x b p e

opcode 1 1 1 0 disp

n=1, i=1, b=1, p=0, TA=(B)+disp (0disp 4095)

• Program-Counter Relative Addressing Mode

n i x b p e

opcode 1 1 0 1 disp

n=1, i=1, b=0, p=1, TA=(PC)+disp (-2048disp 2047)


• Direct Addressing Mode

n i x b p e

opcode 1 1 0 0 disp

n=1, i=1, b=0, p=0, TA=disp (0disp 4095)

n i x b p e

opcode 1 1 1 0 0 disp

n=1, i=1, b=0, p=0, TA=(X)+disp

(with index addressing mode)


• Immediate Addressing Mode

n i x b p e

opcode 0 1 0 disp

n=0, i=1, x=0, operand=disp

• Indirect Addressing Mode

n i x b p e

opcode 1 0 0 disp

n=1, i=0, x=0, TA=(disp)


• Simple Addressing Mode

n i x b p e

opcode 0 0 disp

i=0, n=0, TA=bpe+disp (SIC standard)

n i x b p e

opcode 1 1 disp

i=1, n=1, TA=disp (SIC/XE standard)

SIC/XE Machine Architecture (10/13)• Addressing Modes Summary (p.499)

SIC/XE Machine Architecture (11/13)• Instruction Format


• Instruction Set– Instructions to load and store the new registers

• LDB, STB, etc.

– Floating-point arithmetic operations• ADDF, SUBF, MULF, DIVF

– Register move instruction• RMO

– Register-to-register arithmetic operations• ADDR, SUBR, MULR, DIVR

– Supervisor call instruction• SVC


• Input and Output– There are I/O channels that can be used to

perform input and output while the CPU is executing other instructions

SIC/XE Programming Examples (Fig 1.2b)

LDA #5STA ALPHALDCH #90STCH C1...

ALPHA RESW 1

C1 RESB 1

LDA FIVESTA ALPHALDCH CHARZSTCH C1...

ALPHA RESW 1

FIVE WORD 5

CHARZ BYTE C’Z’

C1 RESB 1

SIC version SIC/XE version

SIC/XE Programming Example (Fig 1.3b)LDS INCRLDA ALPHAADDR S,ASUB #1STA BETALDA GAMMAADDR S,ASUB #1STA DELTA......

ALPHA RESW 1 one-word variablesBETA RESW 1GAMMA RESW 1DELTA RESW 1INCR RESW 1

SIC/XE Programming Example (Fig 1.4b)

LDT #11 initialize register T to 11LDX #0 initialize index register to 0

MOVECH LDCH STR1,X load char from STR1 to reg ASTCH STR2,X store char into STR2TIXR T add 1 to index, compare to 11JLT MOVECH loop if “less than” 11...

STR1 BYTE C’TEST STRING’STR2 RESB 11


LDS #3LDT #300LDX #0

ADDLP LDA ALPHA,X load from ALPHA to reg AADD BETA,XSTA GAMMA,X store in a word in GAMMAADDR S,X add 3 to index valueCOMPR X,T compare to 300JLT ADDLP loop if less than 300......

ALPHA RESW 100 array variables—100 words eachBETA RESW 100GAMMA RESW 100

cs2422 assembly language & system programming

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