IPC@CHIP Documentation - SC12 @CHIP-RTOS V1.10

BX
DX
Handle
Device data
Return Value
Comments
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Success: Carry flag cleared, Device data in DX.
Failure: Carry flag set, AX holds error code
AX=1: Invalid function (wrong value in AL)
AX=6: Invalid handle
If bit 7 of the data is 1, the handle refers to a device and data bit assignments are as follows:
Bit Meaning when bit is set to '1'
B15 Reserved
B14 Device can handle function 0x44, codes 2 and 3
B13 Device supports output until busy
B12 Reserved
B11 Device understands open/close
B10-8 Reserved
B7 '1' indicates handle refers to a device
B6 Not "end of file" on input
B5 Don't check for control characters
B4 Reserved
B3 Clock device
B2 Null device
B1 Console Output device
B0 Console Input device
If bit 7 of the data is 0, the handle refers to a file and data bit assignments are as follows:
Bit Meaning
B15-8 Reserved
B7 Set to '0' to indicate handle refers to a file.
B6 Set to '0' when the file has been written
B0-5 Drive number (0=A, 1=B, etc)
The first three file handles are used for the stdio devices:
0: Input
1: Output
2: Error
This service was implemented to be compatible with the older DOS compilers. The data is saved when
you issue a write, but the data is not used by the @CHIP-RTOS. Control characters are not recognized
as such. Function 0x44 codes 2 and 3 are not supported.
Interrupt 0x21 service 0x47: Get Current Working Directory
Gets the current working directory for a drive.
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