IBM PC CONVERTIBLE Technical Reference page 257

LREG_TAB
10F4 M7 LABEL BYTE ; TABLE OF MODE SETS
10F4 2C 28 20 29 2A 2E DB 2CH,28H,2DH,29H,2AH,2EH,IEH,29H
IE 29
Memory Interrupt Hex 12
(MEMORY _SIZE_DET)
1841
1841
1841 IE
1842 E8 085C R
1845 Al 0013 R
1848 IF
1849 CF
184A
; - - - I NT 12 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - --
MEMORLS I ZCDET
THIS ROUTINE DETERMINES THE AMOUNT OF MEMORY IN THE SYSTEM
AS REPRESENTED BY MEMORLSIZE WORD. THE MEMORLSIZE WORD IS SET
BY POST WHEN IT HAS DETERMINED HOW MUCH MEMORY IS USABLE. IT IS
SET IN lK INCREMENTS ON 8K BYTE BOUNDRIES
INPUT
NO REGISTERS
OUTPUT
(AX) = NUMBER OF CONTIGUOUS lK BLOCKS OF MEMORY
; ORG
AS DETERMINED BY THE POWER ON SELF TEST ROUTINE
ASSUME OS: DATA
OF841H
ORG 01841H
MEMORLSIZE_DET PROC FAR
PUSH OS
CALL DDS
MOV AX,MEMORLSlZE
POP OS
IRET
MEMORLSIZE_DET ENDP
SAVE SEGMENT
GET VALUE
RECOVER SEGMENT
RETURN TO CALLER
Equipment Interrupt Hex 11
(EQUIPMENT)
;--- INT 11 -----------------------------------------------------
EQUIPMENT DETERMINATION
INPUT
OUTPUT
THIS ROUTINE ATEMPTS TO DETERMINE WHAT OPTIONAL
DEVICES ARE ATTACHED TO THE SYSTEM.
NO REGISTERS
THE EQUIPJLAG VARIABLE IS SET DURING THE POWER ON
DIAGNOSTICS USING THE FOLLOWING HARDWARE ASSUMPTIONS:
PORT 3FA = INTERRUPT ID REGISTER OF 8250
BITS 7-3 ARE ALWAYS 0
PORT 378 = OUTPUT PORT OF PRINTER -- 8255 PORT THAT
CAN BE READ AS WELL AS WRITTEN
(AX) IS SET, BIT SIGNIFICANT, TO INDICATE ATTACHED 1/0
BIT 15,14 = NUMBER OF PRINTERS ATTACHED
BIT 13 = INTERNAL MODEM INSTALLED
BIT 12 = GAME 1/0 ATTACHED
BIT 11,10,9 = NUMBER OF SERIAL COMM DEVICES ATTACHED
BIT 8 UNUSED
BIT 7,6 = NUMBER OF DISKETTE DRIVES
00=1, 01=2
BIT 5,4 = INITIAL VIDEO MODE
00 UNUS ED
01 - 40X25 BW USING COLOR CARD
2-232 ROM BIOS