DOS_MAP_B

Categories:

• spectrum
• spectrumAPI

Function	Address	Description
DOS_MAP_A	0154	Map drive B to unit 0 or 1

Synopsys

Map drive B: to unit 0 or unit 1. This routine will fail if drive B: has files open.

If mapping B: to unit 0, then each time unit 0 is accessed, a check is made that the drive mapping is correct. If it isn't, then a reverse call to CHANGE DISK is made, to ask the user to change the disk in unit 0.

If mapping B: to unit 1, then if unit 1 does not exist, drive B: is disabled.

Entry Parameters

Register	Content
C	Unit 0 or 1
HL	Address of change disk routine if unit = 0

Exit Parameters

If OK:

Carry true

A corrupt

HL = Address of previous change disk routine, 0 if none

Otherwise:

Carry false

A corrupt

HL corrupt

Always:

BC DE IX corrupt, all other registers preserved.

Change Disk routine

If you are substituting your own CHANGE DISK subroutine, the 'entry conditions' are the conditions passed to your subroutine, and the 'exit conditions' are registers you are allowed to corrupt.

Entry Parameters

Register	Content
A	Logical drive A…P
HL	Address of message in page 7 terminated by 0xFF

Exit Parameters

Always:

AF BC DE IX corrupt, all other registers preserved.