1, system clock address
0000: 046CH - 4 byte clock counter, automatically adds 1 each time the clock is interrupted. When the system starts, its value is from midnight to the current clock. When the count reaches 24 hours, it is set to 0, and the byte of 0000: 0470H is set to 10000: 0470H - 1 byte This byte is at midnight 1
See INT 8H (clock interruption)
2, display feature data address
0000: 0449H - 1 byte Current display Mode 0000: 044AH - 1 word per line character number (column number) 0000: 044ch - 1 word display buffer bytes 0000: 04EH - 1 word Current display page Map 0000: 0450H - 8 word cursor in the display buffer 0000: 0460H - 1 word Current cursor is the shape of the current cursor. High byte is the label on the line, the low byte is the lower line 0000: 0462H - 1 byte Current display page 0000: 0463H - 1 word CRT control index register port address 0000: 0465H - 1 byte CRT control The current value of the mode register 0000: 0466H - 1 byte CRT controller current value of color registers
See INT 10H (display service interrupt)
3, display buffer address
A000: 0000 - Display content of content graphic display mode
Table 1 Display attribute definition of monochrome display
Background attribute prospect attribute
76543210BLINK BRIGHT
B000: 0000-800H Word Black and White Display Display Text Information, the low byte in each word is the ASCII code of the character, the high byte is the display buffer of its property B800: 0000--2000H word color display. Its character display is the same as the former
Table 2 Show Property of Black and White Display
Background Properties Prospect Properties 7 6 5 4 Property 3 2 1 0 Properties
0 0 0BLACK0 1 1 1REVERSE1 0 0 0BLINK1 1 1 1Reverse Blink
0 0 0 0BLACK0 0 0 1UNDERLINED0 1 1 1NORMAL1 0 0 1Bright underlined1 1 1 1BRight
Table 3 Display Attribute Definition of Color Display
Background attribute prospect attribute
76543210BLINKREDGREENBLUEBRIGHTREDGREENBLUE
Table 4 Display Property of Color Display
Background Properties Prospect Properties 7 6 5 4 Property 3 2 1 0 Properties
0 0 0 0BLACK0 0 1BLUE0 0 1 0Green0 0 1 1 ^ 0 1 0 0BROWN0 1 1WHITE1 0 0 0BLACK BLINK1 0 0 1BLUE BLINK1 0 1 0Green Blink1 0 1 1CYAN BLINK1 1 0 0RED BLINK1 1 0 1MAGENTA BLINK1 1 1 0brown Blink1 1 1 1White Blink
0 0 0 0BLACK0 0 0 1BLUE0 0 1 0Green0 0 1 1CYAN0 1 0 00Brown0 1 1WHITE1 0 0 0DARK GRAY1 0 0 1Light Blue1 0 1 0Light Green1 0 1 1Light Cyan1 1 0 0 011 1 0 1Light Magenta1 1 1 0YELOW1 1 1 1BRIGHT White
4, keyboard address
0000: 0417H - 1 word Current keyboard status correspondence table (see Figure A6.1) 0000: 041AH - 1 word pointing to the header of the keyboard buffer 0000: 041CH - 1 word pointing to the end of the keyboard buffer 0000: 041EH - 16-word default keyboard buffer byte number 0000: 0471H - 1 byte its value is set to 80h, when INT 9H discovers press the combination key ^ Break0000: 0480H - 1 word keyboard buffer queue header 0000: 0482H - 1 word keyboard buffer queue 0000: 0496H - 1 word in its bit 4 = 1, indicating the extension keyboard installed
Figure A6.1 Keyboard status
See INT 09H (keyboard interrupt), int 16h (keyboard service interrupt) and int 1bh (^ Break)
5, interrupt vector table
0000: 0000h - 1024 bytes
See INT 21h's function 25h (set the interrupt number entry address) and 35H (read the interrupt number entry address)
6, system configuration
0000: 0400H - 4-word serial port (COM1 ~ COM4) base address 0000: 0408H - 4-word printer port (LPT1 ~ LPT4) base address 0000: 0410H - 1 word system device table (see Figure A6. 2) 0000: 0413H - 1 word regular memory byyl (in K)
Figure A6.2 System Equipment Table
See INT 11H (Read Device Configuration) and INT 12H (Read General Memory Size)
7, hard drive
0000: 043EH - 1 byte driver flag, its bits 0 to 3 correspond to drive A, B, C, and D. It can know the number of disk drives in the system via INT 11h. 0000: 043FH - 1 byte drive motor logo, its bits 0 ~ 3 correspond to drive A, B, C, and D, respectively. If a bit is 1, the drive that the corresponding drive is rotating. 0000: 0440H - 1 byte driver motor stop time. Its default is approximately 2 seconds, and this value can also be set via INT 13H. 0000: 0441H - 1 byte of the most recent disk operation
00h- Worn 01H- illegal order 02H-address tags No 03H-disk write protection (floppy disk) 04H-sector bit found 08H-DMA overlince (floppy disk) 09h-DMA beyond 64k10h- incorrect CRC data 20H-control Failed 40h - Find failed 80H-disk timeout
See INT 08H (clock interrupt), int 13h (disk service interrupt) and int 1eh (disk parameter table).
8, ROM data
F000: E000H - Change BIOS Release Notes F000: FFFEH - 1 byte System Mode Code F000: FFFFH - 1 byte System Submathesus Code (Mode and Submetal Code Meaning)
9, the address of other content
0000: 0478H - 4 bytes LPT1 and LPT2 loop counters. It affects the timeout judgment of the printer. 0000: 047CH - 4 bytes COM1 ~ COM4 loop counter. It will determine the number of times the MODEM or the online status register. 0000: 0500H - 1 byte indicates the status of the print screen operation:
0 - Success 1 - IN Failed 0000: 0504H - 1 byte Represents Drive Symbol of Single Disk System: 0-A and 1-B
See INT 05H (screen print), int 14h (serial communication service interrupt) and int 17h (printer service)
