IBM PC CONVERTIBLE Technical Reference page 174

0152 2A E4 CP3: SUB AH,AH GOOD RETURN
0154 5A CP4: POP OX
RESTORE REGISTERS
0155 59 POP CX
0156 58 POP
BX
0157
C3 RET
0158
COM_POWER
ENDP
-
--
-
-----
--
-
-
-
-
-
-
- -- - -
-
-- - - - -- - - -
- - -
- - --
WAIT FOR STATUS ROUTINE
ENTRY:
BH=STATUS BIT(S) TO LOOK FOR,
DX=ADDR. OF STATUS REG
EXIT:
ZERO FLAG ON
= STATUS FOUND
ZERO FLAG OFF = TIMEOUT.
AH=LAST STATUS READ
-
--
- -- -- - - - - - - - - - - - - - --
--
- - - - - - - - - - - -- --
0158 WAILFOR_STATUS PROC NEAR
0158 8A 90 007C R MOV BL, RS23LTIM_OUT[DI] LOAD OUTER LOOP COUNT
015C WFSO:
015C 2B C9 SUB CX,CX
015E WFS1:
015E EC IN AL,DX GET STATUS
015F 8A EO
MOV
AH,AL MOVE TO AH
0161
22 C7
AND AL,BH ISOLATE BITS TO TEST
0163 3A C7 CMP AL,BH EXACTL Y = TO MASK
0165 74 08 JE WFS_END RETURN WITH ZERO FLAG ON
0167 E2 F5 LOOP WFSI TRY AGAIN
0169 FE CB DEC
BL
016B
75 EF
JNZ WFSO
0160 OA FF OR
BH, BH SET ZERO FLAG OFF
016F WFS_END:
016F
C3 RET
0170 WAILFOR_STATUS ENDP
0170 COMMO_IO ENDP
ROM BIOS 2-149