mov bx, Handle ;handle of device
mov ch, Category ;device category
mov cl, 45h ;Set Iteration Count
mov dx, seg ItCount
mov ds, dx
mov dx, offset ItCount ;points to buffer for iteration count
mov ax, 440Ch ;IOCTL for Character Device
int 21h
jc error_handler ;carry set means error
Set Iteration Count (Function 440Ch Minor Code 45h) sets the number of times the device driver is to try to send output to a device before assuming that the device is busy.
Handle
Identifies the device to set the iteration count for.
Category
Specifies the type of device. This parameter must be one of the following values:
Value | Device |
01h | Serial device |
03h | Console (screen) |
05h | Parallel printer |
ItCount
Points to a buffer that contains a 16-bit iteration count. The device driver tries to send output to the device until it reaches this number of retries without success.
If the function is successful, the carry flag is clear. Otherwise, the carry flag is set and the AX register contains an error value, which may be one of the following:
Value | Name |
0001h | ERROR_INVALID_FUNCTION |
0006h | ERROR_INVALID_HANDLE |
This function may also return a device-dependent error value as specified by the device driver.
Function 440Ch Minor Code 65h Get Iteration Count