IBM PC CONVERTIBLE Technical Reference page 130

0686
88 46 00 MOV [BP],AL SAVE IN STORAGE AREA
0689 45 INC BP
NEXT LOCATION
068A 8A 84 2000 MOV AL, [S I +2000H]
GET LOWER REGION BYTE
068E 88 46 00 MOV [BP],AL ADJUST AND STORE
0691 45 INC BP
0692 83 C6 50 ADD
SI,80
POINTER INTO REGEN
0695 FE CE DEC DH LOOP CONTROL
0697 75 EB JNZ
S12
DO IT SOME MORE
0699 EB 17 90 JMP S15
GO MATCH SAVED CODE POINTS
;----- MEDIUM RESOLUTION READ
069C S13 :
,.
MED_RES_READ
069C 01 E6
SAL
51,1
OFFSET*2 SINCE 2 BYTES/CHAR
069E B6 04
MOV
DH,4
NUMBER OF PASSES
06AO S14 :
D6AO E8 07lC R CALL 523 GET PAIR BYTES FROM REGEN
INTO SINGLE SAVE
06A3 81 C6 2000 ADD SI,2000H GO TO LOWER REGION
06A7 E8 07lC R CALL S23 GET THIS PAIR INTO SAVE
06AA 81 EE 1FBO SUB S I, 2000H-80
ADJUST PTR BACK INTO UPPER
06AE FE CE DEC DH
06BO 75 EE JNZ
S14 KEEP GOING UNTIL ALL 8 DONE
SAVE AREA HAS CHARACTER IN IT, MATCH IT
06B2 S15 :
; FIND_CHAR
06B2 2B FF SUB 01,01
06B4 8E C7 MOV ES,DI
ASSUME ES: ABSO
06B6 26: C4 3E 0110 R LES DI,CSELPTR ESTABLI SH ADDRESS I NG
ASSUME ES: NOTHING
06BB 83 ED 08 SUB BP ,8 ADJUST POINTER TO BEGINNING
OF SAVE AREA
06BE 8B F5 MOV SI, BP
06CO FC CLD ENSURE 01 RECTI ON
06C1 BO 00 MOV AL,O
CURRENT CD PT BEING MATCHED
06C3 S16:
06C3 16 PUSH SS
ESTAB ADDRESSING TO STACK
06C4 IF POP OS
FOR THE STRING COMPARE
06C5 BA 0080 MOV DX,128
NUMBER TO TEST AGAINST
06C8 S17 :
06C8 56 PUSH SI
SAVE SAVE AREA POINTER
06C9 57 PUSH 01
SAVE CODE POINTER
06CA B9 0008 MOV CX,8 NUMBER OF BYTES TO MATCH
06CD F3/ A6 REPE CMPSB
COMPARE THE 8 BYTES
06CF 5F POP 01 RECOVER THE POINTERS
0600 5E POP SI
0601 74 IE JZ S18 I F ZERO FLAG SET, MATCH
0603 FE CO INC AL
NO MATCH, MOVE ON TO NEXT
0605 83 C7 08 ADD 01,8 NEXT CODE POINT
0608 4A DEC OX
LOOP CONTROL
0609 75 ED
JNZ S17 DO ALL OF THEM
CHAR NOT MATCHED, MIGHT BE IN USER SUPPLI ED SECOND HALF
06DB 3C 00 CMP AL,O AL
<>
0 I F 1ST HALF SCANNED
0600 74 12 JE S18 IF" 0, IF ALL SCANNED
06DF 2B CO SUB AX,AX
06El 8E 08 MOV DS,AX ESTAB ADDRESSING TO VECTOR
ASSUME OS :ABSO
06E3 C4 3E 007C LES
DI,EXLPTR GET POINTER
06E7 8C CO MOV AX, ES SEE I F POINTER REALLY EXISTS
06E9
OB C7 OR AX,DI IF ALL 0, THEN DOESN'T EXIST
06EB 74 04 JZ S18 NO SENSE LOOKING
06ED BO 80 MOV AL,128
ORIGIN FOR SECOND HALF
06EF EB 02 JMP S16 GO BACK AND TRY FOR IT
ASSUME DS:DATA
CHARACTER IS FOUND ( AL"O IF NOT FOUND )
06F1 S18:
06Fl
83 C4 08 ADD
SP ,8
; READJUST, THROW AWAY SAVE
ROM BIOS 2-105