1. Video systems (continue)

2. Practice Modify the program to get a string from a keyboard to display the input string on the middle of the screen with reverse video Hint: Using INT 10H function 13H (last week’s slide) with 17H as attribute Review for midterm exam

3. Review (Week 4 and 3) Determine the instruction address for the following given values for CS and IP: (a) CS = 26AE[0], IP = 0044; Instruction address= 26B24H; (b) CS = 25BD[0], IP = 003F; Instruction address= 25C0FH; (c) CS = 272D[0], IP = 029C. Instruction address= 2756C.

4. Review 2. The BIOS Data Area begins in low memory at segment address_40[0]H__________ 4. A __directive__ enables you to control the way in which a program assembles and lists. 5. The first byte of an instruction is the _operation__; the other bytes are _operand__, which reference an immediate value, register, or memory location.

5. Review 3. The value 2505H is stored in locations 130 and 131, and 1C04H is stored in locations 132 and 133. What is the effect of the following related instructions? (a) MOV BX,[0130] 0525H in BX (b) ADD BX,[0132] 0941H in BX (c) MOV [0134],BX 4109H in locations 0134 and 0135.

6. Review 6. The expression in an operand of a data item may contain a _____?__ to indicate an uninitialized item. 7. The statement DW 10 DUP(25) defines 10 word__ initialized with the value _25__. 8. A comment following an instruction on the same line is preceded by what character? (a) * (b) ; (c) : (d) a blank

7. Review 6. The expression in an operand of a data item may contain a _____?__ to indicate an uninitialized item. 7. The statement DW 10 DUP(25) defines 10 word__ initialized with the value _25__. 8. A comment following an instruction on the same line is preceded by what character? (a) * (b) ; (c) : (d) a blank

8. Using Graphic Mode Graphic mode uses pixels to generate color patterns. It represents a pixel from one to eights bits There are 10 common graphic modes. They are different in terms of # pages, #colors, resolution. EMU8086 supports 1 graphic mode (INT 10H, function 13H): – Page 1, Resolution: 320 x 200, 256 colors

9. Setting graphic mode INT 10H, function 00H Step 1: Set AL = 13H Step 2: Set AH =0 Step 3: Call INT 10H

10. Direct Video Display Fastest way to display text or graphic characters is to transfer them directly to video display area The address of page 0 for mode 3 is B800[0]H. Each character require two bytes (one for representing the character itself and one for its attribute) Moving a pair of character:attribute into video area of the active page will cause the character appear immediately on screen

11. Example of direct video display MOV AX, 0B800h MOV ES, AX ; print message using ES ; as segment: MOV ES:[00h], 48h;H MOV ES:[02H], 45h;E MOV ES:[04H], 4ch;L MOV ES:[06H], 4ch;L MOV ES:[08H], 4fh;O

12. Example of direct video display

13. MOV AX, 0B800H MOV ES, AX MOV AX, 0003H ; Set the current video mode to text mode INT 10H ; INT 10H, function 00H (mode=03H is standard text) MOV AX, 0500H ; Set the active page = 00 INT 10H CALL DISPLAY

14. Example of direct video display DISPLAY PROC NEAR mov cx,25;vertical line mov di,0 again1: mov es:[di],48h mov es:[di+1],4eh add di,80 loop again1 DISPLAY ENDP

15. Direct Video Display

16. Direct video display Practice Modify the previous program to draw horizontal line on the screen using direct video display

17. Review exercise (Week 1 and 2) 1. The smallest unit of data in a computer is a _bit___. It may be off so that its value is __0___, or on so that its value is __1__. 2. In a byte, the parity bit always requires that the number of bits on is a(n) ___odd___ number. 3.The number 2 10 equals _1024_____, which is represented by the letter _K_, for kilobyte. 4.A negative binary number contains a __1___ in its leftmost position. A negative value is expressed in what is called __two’s complement__________ notation.

18. Review exercise (Week 1 and 2) 5. The _hexadecimal_____ (base 16) numbering system involves the digits 0 through F. To indicate a base 16 number in a program, you code the letter _H_ immediately after the number. 6. A segment is an area that begins on a _paragraph__________ boundary, that is, at any location evenly divisible by decimal 16__, or hex 10__.A segment may be located almost anywhere in memory and in real mode may be up to _64K___ bytes in size. 7. Within a program, memory locations are relative to the start of a __segment________; the distance in bytes is expressed as a(n) __offset______ from its start.

19. Review exercise (Week 1 and 2) 8. To convert a binary number into its two's complement form (a) add 1, (b) reverse the bit values, (c) reverse the bit values and add 1, (d) reverse the bit values and subtract 1. 9. Reverse-byte sequence means that the processor stores (a) byte values upside down, (b) byte addresses backwards, (c) numeric values with bytes in reverse sequence, (d) all values with bytes in reverse sequence.

20. Review exercise (Week 1 and 2) 10. The general purpose registers are (a) AX, BX, CX, DX (b) SP, BP, IP (c) DI, SI (d) CS, DS, ES, SS 11. The index registers are the (a) AX, BX, CX, DX (b) SP, BP, IP (c) DI, SI(d) CS, DS, ES, SS 12.What is the maximum size of a segment? (a) 4K (b) 64K (c) 256K (d) no limit

21. Review exercise (Week 1 and 2) 13. Provide the two instructions to initialize the address of the data segment in the DS register, given the name DATSG. MOV AX,DATSG MOV DS,AX

22. Review exercise (Week 1 and 2) 14.

23. Practice 2B360H PSP Stack Segment Data Segment Code Segment Memory SS=2B360H+100H =2B46[0]H CS=2B360H+100H + 30H + 70H =2B50[0]H DS=2B36[0]H ES=2B36[0]H SP=0030H