input:
AL = desired video mode.
These video modes are supported:
00h - Text mode 40x25, 16 colors, 8 pages.
03h - Text mode 80x25, 16 colors, 8 pages. input:
CH = cursor start line (bits 0-4) and options (bits 5-7).
CL = bottom cursor line (bits 0-4).
When bits 6-5 of CH are set to 00, the cursor is visible, to hide a cursor set these bits to 01 (this CH value will hide a cursor: 28h - 00101000b). Bit 7 should always be zero. input:
DH = row.
DL = column.
BH = page number (0..7).input:
BH = page number.
return:
DH = row.
DL = column.
CH = cursor start line.
CL = cursor bottom line.input:
AL = new page number (0..7).
the activated page is displayed. input:
AL = number of lines by which to scroll (00h = clear entire window).
BH = attribute used to write blank lines at bottom of window.
CH, CL = row, column of window's upper left corner.
DH, DL = row, column of window's lower right corner.input:
BH = page number.
return:
AH = attribute.
AL = character.input:
AL = character to display.
BH = page number.
BL = attribute.
CX = number of times to write character.input:
AL = character to display.
BH = page number.
CX = number of times to write character.input:
AL = character to write. This functions displays a character on the screen, advancing the cursor and scrolling the screen as necessary. The printing is always done to current active page.
input:
AL = write mode:
bit 0: update cursor after writing;
bit 1: string contains attributes.
BH = page number.
BL = attribute if string contains only characters (bit 1 of AL is zero).
CX = number of characters in string (attributes are not counted).
DL,DH = column, row at which to start writing.
ES:BP points to string to be printed. input:
BL = write mode:
0: enable intensive colors.
1: enable blinking (not supported by emulator!).
BH = 0 (to avoid problems on some adapters).Bit color table: Character attribute is 8 bit value, low 4 bits set foreground color, high 4 bits set background color. Background blinking not supported.
HEX BIN COLOR
0 0000 black 1 0001 blue 2 0010 green 3 0011 cyan 4 0100 red 5 0101 magenta 6 0110 brown 7 0111 light gray 8 1000 dark gray 9 1001 light blue A 1010 light green B 1011 light cyan C 1100 light red D 1101 light magenta E 1110 yellow F 1111 white
return:
AX = BIOS equipment list word, actually this call returns the contents of the word at 0040h:0010h.
Currently this function can be used to determine the number of installed number of floppy disk drives.
Bit fields for BIOS-detected installed hardware:
Bit(s) Description
15-14 number of parallel devices.
13 not supported.
12 game port installed.
11-9 number of serial devices.
8 reserved.
7-6 number of floppy disk drives (minus 1):
00 single floppy disk;
01 two floppy disks;
10 three floppy disks;
11 four floppy disks.
5-4 initial video mode:
00 EGA,VGA,PGA, or other with on-board video BIOS;
01 40x25 CGA color;
10 80x25 CGA color (emulator default);
11 80x25 mono text.
3 not supported.
2 not supported.
1 math coprocessor installed.
0 set when booted from floppy (always set by emulator).return:
AX = kilobytes of contiguous memory starting at absolute address 00000h, this call returns the contents of the word at 0040h:0013h. Floppy drives are emulated using FLOPPY_0(..3) files.
input:
AL = number of sectors to read/write (must be nonzero)
CH = cylinder number (0..79).
CL = sector number (1..18).
DH = head number (0..1).
DL = drive number (0..3 , depends on quantity of FLOPPY_? files).
ES:BX points to data buffer.
return:
CF set on error.
CF clear if successful.
AH = status (0 - if successful).
AL = number of sectors transferred.
Note: each sector has 512 bytes. input:
CX:DX = interval in microseconds
return:
CF clear if successful (wait interval elapsed),
CF set on error or when wait function is already in progress.
Note:
the resolution of the wait period is 977 microseconds on many systems, Emu8086 uses 1000 microseconds period. return:
AH = BIOS scan code.
AL = ASCII character.
(if a keystroke is present, it is removed from the keyboard buffer). return:
ZF = 1 if keystroke is not available.
ZF = 0 if keystroke available.
AH = BIOS scan code.
AL = ASCII character.
(if a keystroke is present, it is not removed from the keyboard buffer). Usually, the BIOS will try to read sector 1, head 0, track 0 from drive A: to 0000h:7C00h. Emulator just stops the execution, to boot from floppy drive select from the menu: 'Virtual Drive' -> 'Boot from Floppy' return:
CX:DX = number of clock ticks since midnight.
AL = midnight counter, advanced each time midnight passes.Notes: There are approximately 18.20648 clock ticks per second, and 1800B0h per 24 hours. AL is not set by emulator yet!
MS-DOS can not be loaded completely in emulator yet, so I made an emulation for some basic DOS interrupts also: