5F1Ch – BIOS Pipe Access

This function will set the BIOS pipe access or return the BIOS pipe access status.

5F1Ch, 00h – Set BIOS Pipe Access

This sub-function will set the currently selected pipe. All 5f functions operate on the currently selected pipe.

When not in clone modes this value cannot be set.

Calling Registers:

AX = 5F1Ch, BIOS Pipe Access function

BH = 00h, Set BIOS Pipe Access sub-function

CH = BIOS Pipe access:

= 00h, Pipe A

= 01h, Pipe B

Return Registers:

AX = Return Status (function not supported if AL != 5Fh):

= 005Fh, Function supported and successful

= 015Fh, Function supported but failed

5F1Ch, 01h – Get BIOS Pipe Access

This sub-function will return the currently selected pipe.

Calling Registers:

AX = 5F1Ch, BIOS Pipe Access function

BH = 01h, Get BIOS Pipe Access sub-function

Return Registers:

AX = Return Status (function not supported if AL != 5Fh):

= 005Fh, Function supported and successful

= 015Fh, Function supported but failed

CH = BIOS Pipe access:

= 00h, Pipe A

= 01h, Pipe B