Specifications

Software Configuration
3–27
;----------------------------------------------------------
; Page select code for byte-wide sockets
;----------------------------------------------------------
MOV AH,0CDH ; AMPRO function call
MOV AL,nn ; Use 03 for S0, 04 for S1
MOV BL,nn ; Use 01 to turn ON or 00 to turn OFF
MOV BH,x0h ; The upper nibble of BH contains the page
; number for devices larger than 64 K.
INT 13H
Device
Size
64KB
Segments
Segment Address
(Upper Nibble of BH)
128K 2 FIRST BH=00h
SECOND BH=10h
256K 4 FIRST BH=00h
SECOND BH=10h
THIRD BH=20h
FOURTH BH=30h
512K 8 FIRST BH=00h
SECOND BH=10h
THIRD BH=20h
FOURTH BH=30h
FIFTH BH=40h
SIXTH BH=50h
SEVENTH BH=60h
EIGHTH BH=70h
1M 16 FIRST BH=00h
SECOND BH=10h
THIRD BH=20h
FOURTH BH=30h
FIFTH BH=40h
SIXTH BH=50h
SEVENTH BH=60h
EIGHTH BH=70h
NINTH BH=80h
TENTH BH=90h
ELEVENTH BH=A0h
TWELFTH BH=B0h
THIRTEENTH BH=C0h
FOURTEENTH BH=D0h
FIFTEENTH BH=E0h
SIXTEENTH BH=F0h
NOTE: For a 128K byte window, use any of the odd
numbered values (for instance, FIRST or THIRD)
Table 3-11 Segment Addressing in Large Memory Devices