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Text File | 1990-01-04 | 32.8 KB | 824 lines

.VGA BIOS STARTING ADDRESS: .VGA BIOS SIZE: .VGA ROM BIOS main feature : 1. Video adapter diagnostic (self-test) 2. Video service routines 3. ASCII code table 4. Video parameter table .I/O ROM construction: 1. The first word: 55 AA as identifier 2. Byte 02: total length /512 3. Jump instruction .MAIN FEATURE: 1.DIAGNOSTIC: 2.SERVICE ROUTINE: .BACKWARD CAPABILITY: .MEMORY CONFIGURATION: .NMI: Sequence: 1. Disable VGA 2. Check if other display card exists? write 4 words to VRAM (B000 & B800) read back If VRAM R/W O.K then set equip_flag and CF 3. Enable VGA and access I/O 4. Set fixed vector (Note 1) INT 10h : INT 1Fh : 2nd 128 8x8 ASCII code INT 43h : 1st 128 8x8 ASCII code INT 1Dh : INT 6dh : INT 42h : IBM (CGA,MDA,MGA) original INT 10 vector (F000:F065) 5. Test video RAM By writing a pattern to VRAM then reading it back If an error occurs, sound 1 long and 2 short error beeps. 6. Sense monitor type R G B -- 12h,12h,12h : If port 3C2h bit 4 on, color monitor is attached R G B -- 4,12h,4 : If port 3C2h bit 4 on, mono monitor is attached else, no monitor is attached. 7. Dual (alternative) monitor test Set corresponding and relative flags 8. Set CRT mode according to the current flags setting 9. Test vertical retrace signal Read input status register, if an error occurrs, sound 1 long and 3 short error beeps. 10. Show ACER copyright **************************************** * * ****** INTRODUCTION ******** * * **************************************** A. VIDEO MODE : 1. Text mode 2. Graphics mode B. DISPLAY MEMORY ORGANIZATION C. CHARACTER GENERATOR D. COLOR PALETTE AND COLOR REGISTER E. GRAPHICS READ AND WRITE MODES 1. Write modes : 0-3 2. Read modes : 0-1 F. VGA REGISTER 1. General or External registers 2. Sequencer registers 3. CRTC registers 4. Graphics registers 5. Attribute registers G. VGA BIOS DATA AREA H. VIDEO BIOS SERVICE ROUTINES ************************************ * * ******* TEXT MODES ******* * * ************************************ ┌────────────────────────────────────────────────────────────────────────────────┐ │ Mode Type of #Chars Display Page Resolution Buffer │ │ Adapter (X/Y) Char Box Format no. in Pixels │ ├────────────────────────────────────────────────────────────────────────────────│ │ 0,1 EGA/VGA 40/25 8 x 8 16/256K 8 320 x 200 B8000 │ ├────────────────────────────────────────────────────────────────────────────────│ │ 0*,1* EGA/VGA 40/25 8 x 14 16/256K 8 320 x 350 B8000 │ ├────────────────────────────────────────────────────────────────────────────────│ │ 0+,1+ VGA 40/25 8 x 16 16/256K 8 320 x 400 B8000 │ ├────────────────────────────────────────────────────────────────────────────────│ │ 2,3 EGA/VGA 80/25 8 x 8 16/256K 8 640 x 200 B8000 │ ├────────────────────────────────────────────────────────────────────────────────│ │ 2*,3* EGA/VGA 80/25 8 x 14 16/256K 8 640 x 350 B8000 │ ├────────────────────────────────────────────────────────────────────────────────│ │ 2+,3+ VGA 80/25 8 x 16 16/256K 8 640 x 400 B8000 │ ├────────────────────────────────────────────────────────────────────────────────│ │ 7 EGA/VGA 80/25 9 x 14 bw 8 720 x 350 B0000 │ ├────────────────────────────────────────────────────────────────────────────────│ │ 7+ VGA 80/25 9 x 16 bw 8 720 x 400 B0000 │ └────────────────────────────────────────────────────────────────────────────────┘ Notes: 1. The asterisk (*) in the display mode indicates that the VGA is in a text mode with 350 vertical lines. 2. The plus (+) in the display mode indicates that the VGA is in a text mode with 400 vertical lines. 3. Display modes 0 through 6 emulate the Color Graphics Adapter(CGA). Mode 7 emulates the IBM Monochrome MDA or Hercules Monochrome graphics. 4. The code "bw" stands for black and white or synonymously monochrome. ************************************ * * ******* GRAPHICS MODES ******* * * ************************************ ┌─────────────────────────────────────────────────────────────────────────────┐ │ Mode #Chars Display Page Resolution Buffer │ │ (Hex) Adapter (X/Y) Char Box Format no. in Pixels │ ├─────────────────────────────────────────────────────────────────────────────│ │ 4,5 EGA/VGA 40/25 8 x 8 4/256K 1 320 x 200 B8000 │ ├─────────────────────────────────────────────────────────────────────────────│ │ 6 EGA/VGA 80/25 8 x 8 2/256K 1 640 x 350 B8000 │ ├─────────────────────────────────────────────────────────────────────────────│ │ D EGA/VGA 40/25 8 x 8 16/256K 8 320 x 200 A0000 │ ├─────────────────────────────────────────────────────────────────────────────│ │ E EGA/VGA 80/25 8 x 8 16/256K 4 640 x 200 A0000 │ ├─────────────────────────────────────────────────────────────────────────────│ │ F EGA/VGA 80/25 8 x 14 bw 2 640 x 350 A0000 │ ├─────────────────────────────────────────────────────────────────────────────│ │ 10 EGA/VGA 80/25 8 x 14 16/256K 2 640 x 350 A0000 │ ├─────────────────────────────────────────────────────────────────────────────│ │ 11 VGA 80/30 8 x 16 2/256K 1 640 x 480 A0000 │ ├──────────────────────────────────────────────────────────────────────────── │ │ 12 VGA 80/30 8 x 16 16/256K 1 640 x 480 A0000 │ ├─────────────────────────────────────────────────────────────────────────────┤ │ 13 VGA 40/25 8 x 8 256/256K 1 320 x 200 A0000 │ └─────────────────────────────────────────────────────────────────────────────┘ ┌────────────────────────────────────────────────────────────────────────┐ │ MODE │ │ (Hex) # of Colors # Bits per Plane Bit Planes Affected Notes │ ├────────────────────────────────────────────────────────────────────────┤ │ 4,5 4 2 0,1 1 │ ├────────────────────────────────────────────────────────────────────────│ │ 6 2 1 0 2 │ ├────────────────────────────────────────────────────────────────────────│ │ D 16 1 0,1,2,3 3 │ ├────────────────────────────────────────────────────────────────────────│ │ E 16 1 0,1,2,3 3 │ ├────────────────────────────────────────────────────────────────────────│ │ F 4 1 0,2 4 │ ├────────────────────────────────────────────────────────────────────────│ │ 10 16 1 0,1,2,3 3 │ ├────────────────────────────────────────────────────────────────────────│ │ 11 2 1 0 2 │ ├────────────────────────────────────────────────────────────────────────│ │ 12 16 1 0,1,2,3 3 │ ├────────────────────────────────────────────────────────────────────────┤ │ 13 256 8 0,1,2 or 3 5 │ └────────────────────────────────────────────────────────────────────────┘ Notes: 1.In modes 4 and 5, alternate bytes of data, each containing four pixels, are stored in bit plane 0 and bit plane 1. Bit plane 0 contributes to the low-order bit, and bit plane 1 contributes to the high-order bit of the two-bit pixel. 2.In modes 6 and 11 hex, each pixel consists of one bit in bit plane 0. 3.In mode D,E,10,12 hex, each pixel corresponds to one bit in each of the four bit planes. Bit plane 0 contributes to the low-order bit, followed by bit plane 1, and bit plane 2. Bit plane 3 contributes to the high-order bit of the four bit pixel. 4.In mode F hex, bit plane 0 contributes to the low-order bit and bit plane 2 contributes the high-order bit of the two bit pixel. 5.In mode 13 hex, all four bit planes are chained together and each pixel consists of eight bits. The plane in which a pixel resides depends on the position of the pixel on the display. Each plane holds one-quarter of the pixels. ************************************ * * ******* CHARACTER FONTS ******* * * ************************************ There are 5 character fonts set supported: 8 by 8 ,8 by 14, 8 by 16, 9 by 14, and 9 by 16. The 9 by 14 and 9 by 16 character font are referred to as the supplement character set. It is called supplemental because not all of the 256 characters are provided. Typical characters that are included in the supplement are quotation marks ("),the plus sign (+), the minus sign (-), M,T,V,W,X,Y,Z,m,v,w and line-drawing symbols. ************************************ * * **** CHARACTER ATTRIBUTE **** * * ************************************ A. MONOCHROME MODE Mode 7: Monochrome Attributes ────────────────────────────────────────────────────────────────────────────── Background (bits 6-4) Foreground (bits 2-0) Attribute ────────────────────────────────────────────────────────────────────────────── 0 0 Black 0 1 Underline 0 7 Normal (white on black) 7 0 Reversed (black on white) 7 7 White Mode 7: Examples of Monochrome Attributes ──────────────────────────────────────────────────────────────────────── Blink Background Intens Foreground Code (Bit 7) (bits 6-4) (Bit 3) (Bit 2-0) (Hex) Attribute ──────────────────────────────────────────────────────────────────────── 0 0 0 1 1 Underline 0 0 1 1 9 Intense Underline 0 7 0 0 70 Reversed 0 7 1 0 74 Intense Reversed 1 7 0 0 F0 Blinking Reversed 1 7 1 0 F1 Intense Blinking Reserved Mode 7: Palette Registers ─────────────────────────────────────────────────────────────────────── Register # Register Value Register # Register Value ─────────────────────────────────────────────────────────────────────── 0 00 8 10 1 08 9 18 2 08 A 18 3 08 B 18 4 08 C 18 5 08 D 18 6 08 E 18 7 08 F 18 B. SIXTEEN-COLOR MODE Default Colors for a 16-color Palette ──────────────────────────────────────────────── Palette Register (Hex) Color ──────────────────────────────────────────────── 0 Black 1 Blue 2 Green 3 Cyan 4 Red 5 Magenta 6 Brown 7 White 8 Gray 9 Light Blue A Light Green B Light cyan C Light red D Light Magenta E Light Brown (yellow) F Bright White C. ATTRIBUTE BYTE IN THE 16-COLOR MODE 7 6 5 4 3 2 1 0 ┌──────────────────────┬──────────────────────┐ │ │ │ └──────────────────────┴──────────────────────┘ Background Foreground 7 6 5 4 3 2 1 0 ┌──────────────────────┬────┬─────────────────┐ │ │ │ │ └──────────────────────┴─┼──┴─────────────────┘ Background │ Forground Font # 7 6 5 4 3 2 1 0 ┌───┬──────────────────┬──────────────────────┐ │ │ │ │ └─┼─┴──────────────────┴──────────────────────┘ │ Background Foreground Blinking 7 6 5 4 3 2 1 0 ┌───┬──────────────────┬───┬──────────────────┐ │ │ │ │ │ └─┼─┴──────────────────┴─┼─┴──────────────────┘ │ Background │ Foreground Blinking Font # Note: 1. The character attribute byte determines the character color, blinking status and selects from one of the two character sets. Bit 3 of the character attribute byte is used either to select one of 16 foreground colors for the associated character or to choose from one of two resident character sets. Bit 7 is selected for dual function; either being part of the background color code or being a switch for the blinking feature. 2. The default alphanumeric characters are defined by the bit patterns in the first table in MAP 2, regardless of the value of bit 3 of the attribute bytes of the characters displayed. Changing the value in the Character Map Select register, changes the character definition tables associated with bit 3 of the attribute bytes. If two different values appear in the bit fields in the Character Map Select register, the value of bit 3 designates one of the two different character definition tables. ************************************ * * ******* VGA REGISTERS ****** * * ************************************ General or External Registers _____________________________________________________________________________ Name Write (Hex) Read (Hex) Misc. Output 3C2 3CC Feature Control 3DA/3BA 3CA Input Status #0 3C2 Input Status #1 3DA/3BA _____________________________________________________________________________ Sequencer Registers _____________________________________________________________________________ Name Index R/W Port(Hex) Address x 3C4 Reset 0 3C5 Clocking Mode 1 3C5 Map Mask 2 3C5 Character Map Select 3 3C5 Memory Mode 4 3C5 _____________________________________________________________________________ Attribute Controller Registers _____________________________________________________________________________ Name Index R/W Port(Hex) Address x 3C0 Palette 0-F 3C1 Mode Control 10 3C1 Overscan Color 11 3C1 Color Plane Enable 12 3C1 Horizontal Pixel Panning 13 3C1 Color Select 14 3C1 _____________________________________________________________________________ Graphics Control Registers: _____________________________________________________________________________ Name Index R/W Port(Hex) Graphics Address x 3CE Set/Reset 0 3CF Enable Set/Reset 1 3CF Color Compare 2 3CF Data Rotate 3 3CF Read Map Select 4 3CF Mode 5 3CF Miscellaneous 6 3CF Color Don't Care 7 3CF Bit Mask 8 3CF _____________________________________________________________________________ CRT Controller Registers _____________________________________________________________________________ Name Index R/W Port(Hex) Address Horizontal Total Horizontal Display End Start Horizontal Blank End Horizontal Blank Start Horizontal Retrace End Horizontal Retrace Vertical Total Overflow Preset Row Scan Max Scan Line Cursor Start Cursor End Start Address High Start Address Low Cursor Location High Cursor Location Low Vertical Retrace Start Vertical Retrace Low Vertical Display End Offset Underline Location Start Vertical Blank End Vertical Blank Mode Control Line Compare _____________________________________________________________________________ ************************************ * * ******* MEMORY MAPPING ****** * * ************************************ The video buffer can be configured as the following : 1). A000:0 ------- 128K for mode D,E,F,10,11,12 and 13 2). A000:0 ------- 64K for character generator for text modes 3). B000:0 ------- 32k for mode 7 and 7+ 4). B800:0 ------- 32K for text mode 0,1,2,3 and graphics modes 4,5,6 ************************************ * * ******* CHARACTER GENERATOR ****** * * ************************************ The character generator consists of the dot patterns that represent each character in the character set. The character dot patterns are stored in character boxes, each of which is 32 bytes long. Bits set to 1 in the character font will be displayed in the foreground color, and bits reset to 0 will be displayed in the background color. The display memory consists of four display planes called bit planes, each being 64K bytes long. VGA supports eight font tables. Each table consists of 256 32-byte bit patterns, so the character box height is 32 scan lines. When the displayed character box contains fewer than 32 lines, the character generator ignores the extra bytes in each character definition. The character generator has 8 blocks as shown below: A000:0 ╔═════════╗ ┌────────────────────┐ ║ Font 0 ─╫──────── 0 │ 0 │ 2000 ╟─────────║ ├────────────────────│ ║ Font 4 ║ 1 │ 1 │ 4000 ╠═════════╣ ├────────────────────│ character 0 ║ Font 1 ║ │ . │ 6000 ╟─────────║ │ . │ ║ Font 5 ║ │ . │ 8000 ╠═════════╣ ├────────────────────│ ║ Font 2 ║ 31 │ 31 │ A000 ╟─────────║ ─────┼────────────────────┼───────── ║ Font 6 ║ 32 │ 0 │ C000 ╠═════════╣ ├────────────────────│ ║ Font 3 ║ │ . │ character 1 E000 ╟─────────║ │ . │ ║ Font 7 ║ │────────────────────│ ╙═════════╝ 63 │ 31 │ ─────┼────────────────────┼───────── 64 │ . │ │ . │ │ . │ ────┼────────────────────┼────────── │ 0 │ ├────────────────────│ │ │ │ │ character 255 ├────────────────────┤ 8191 │ 31 │ └────────────────────┘ *************************************************** * * ******* GRAPHICS MODES PIXEL PROGRAMMING ****** * * *************************************************** A. Relative Registers Accessed: Graphics Control Registers: Name Index R/W Port(Hex) Graphics Address x 3CE Set/Reset 0 3CF Enable Set/Reset 1 3CF Color Compare 2 3CF Data Rotate 3 3CF Read Map Select 4 3CF Mode 5 3CF Miscellaneous 6 3CF Color Don't Care 7 3CF Bit Mask 8 3CF B. Read/Write Mode 1. Write Mode 0 (EGA/VGA) 2. Write Mode 1 (EGA/VGA) 3. Write Mode 2 (EGA/VGA) 4. Write Mode 3 (VGA Only) 5. Read Mode 0 (EGA/VGA) 6. Read Mode 1 (EGA/VGA) *************************************** * * ******* PALETTE/COLOR REGISTER ****** * * *************************************** Palette Utilization ─────────────────────────────────────────────────────────────────────── Display Mode (hex) Number of Colors Palette Register Affected 0,1 16 0-15 2,3 16 0-15 4,5 4 0,1,2,3 6 2 0,1 7 4 0,1,4,5 D 16 0-15 E 16 0-15 F 4 0,1,4,5 10 16 0-15 11 2 0,1 12 16 0-15 13 256 0-15 Mode 7 Palette Defult Values ────────────────────────────────────────────────────────── Register 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 0 8 8 8 8 8 8 8 10 18 18 18 18 18 18 18 ─────────────────────────────────────────────────────────── Mode F Palette Default Values ────────────────────────────────────────────────────────── Register 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 0 8 - - 18 18 - - - - - - - - - - ─────────────────────────────────────────────────────────── Mode 0,1,2,3 Palette Default Values ────────────────────────────────────────────────────────── Register 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 0 1 2 3 4 5 14 7 38 39 3A 3B 3C 3D 3E 3F ─────────────────────────────────────────────────────────── CGA-compatible Color Selection ──────────────────────────────────────────────────────────────── ATR 1 ATR 0 Set 1 Set 0 VGA Palette Register 0 0 Background Background 0 0 1 Cyan Green 1 1 0 Magenta Red 2 1 1 White Brown 3 Mode 6 Palette Default Values ────────────────────────────────────────────────────────── Register 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 0 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 ─────────────────────────────────────────────────────────── Mode 11 Palette Default Values ────────────────────────────────────────────────────────── Register 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 0 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 ─────────────────────────────────────────────────────────── Mode D,E,10 and 12 Palette Default Values ────────────────────────────────────────────────────────── Register 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 0 1 2 3 4 5 14 7 38 39 3A 3B 3C 3D 3E 3F ─────────────────────────────────────────────────────────── Mode 13 Palette Default Values ────────────────────────────────────────────────────────── Register 0 1 2 3 4 5 6 7 8 9 A B C D E F Value 0 1 2 3 4 5 6 7 8 9 A B C D E F ─────────────────────────────────────────────────────────── COLOR REGISTERS The VGA is equipped with 256 Color Registers. A pixel or character in display memory consists of one to eight bits of data. This data is used to address the 16 palette registers. The output of these palette registers is used in conjunction with the data in displaying memory to address the color registers. The color registers contain the color codes that are output to the digital-to-analog converters (DAC). The output of the DAC are sent to the monitor. Each of the color registers consists of a red, green, and blue component. Each of these color components is six bits wide. ************************************ * * ******* VGA BIOS CALLS ****** * * ************************************ CONTROL ___________________________________________________________ Mode Set Select Active Display Page Select Alternate Print Screen Routine Video Enable/Disable Display Switch Video Screen On/Off RETURN STATE ___________________________________________________________ Return Curren Video State Return Video Information Read/Write Displat Combination Code Return Functionality/State Information Save/Restore Video State INTERACTIVE ___________________________________________________________ Set Cursor Type Set Cursor Position Read Cursor Position Cursor Emulation TEXT ___________________________________________________________ Scroll Active Page Up Scroll Active Page Down Read Character/Attribute Write Character/Attribute Write Character Only Write Teletypewriter to Active Page Select Scan Lines for Text Modes Write String GRAPHICS ___________________________________________________________ Write Dot Read Dot PALETTE ___________________________________________________________ Set Color Palette Set Individual Palette Register Set Overscan (Boarder) Register Set All Palette Registers and Overscan Toggle Intensity/Blinking Bit Read Individual Palette Register Read Overscan Resister Read all Palette Registers and Overscan Default Palette Loading During Mode Set COLOR REGISTERS ___________________________________________________________ Set Individual Color Register Set block of Color Registers Select Color Page Read Individual Color Register Read Block of Color Registers Read Current Color Page Number Sum Color Values to Gray Scale Default Palette Loading During Mode Set Summing to Gray Scales CHARACTER GENERATOR ___________________________________________________________ User text Load with Reset ROM Monochrome Set with Reset ROM 8x8 Character Set Load with Reset Set Block Specifier ROM 8x16 Character Set Load with Reset User Alpha Load ROM Monochrome Set ROM 8x8 Character Set Load ROM 8x16 Character Set Load User Graphics Characters INT 1FH (8x8) User Graphics Characters Graphics Mode ROM 8x14 Character Set Load Graphics Mode ROM 8x8 Character Set Load Graphics Mode ROM 8x16 Character Set Load Return Character Generator Information