IBM 5150 - Page 182

LOC OBJ
LINE SOURCE
F4!F 7500 4262 JHZ
R.
; YES. XOR THE DOT
F441 F604 4263 HOT AH
, SET THE MASK TO REMOVE THE
F443 22CC 4264 .HO CL,AH
;
INDICATED BITS
F445 DAtI 4265
00
Al,CL
; OR IN THE NEW VAlUE OF THOSE BITS
F447
4266
Ill: I FINISH_DOT
F447 268804 4267
HOV ES:ISI1.Al
I RESTORE THE BYTE IN MEI'tORY
F44.1. 58 4268
POP
,X
F448 E977FD 4269
JHP VIDEO_RETURN
; RETURN FROI1 VIDEO 10
1"'""""\
F44£ 4270 R2: I XOR_DOT
F44E UtI 42.71
XOR
Al,CL ; EXCLUSIVE OR THE DOTS
0'
F450 EBFS 4272 JHP
I FINISH UP THE WRITING
4273
WRITE_DOT EHOP
4274
;--------------------------------------------------------
4275 I THIS SUBROUTINE DETERMINES THE REGEN BYTE LOCATION
4276 ; OF THE INDICATED ROW COLUMN VALUE IN GRAPHICS MODE.
4277
I ENTRY --
4278 OX = ROW VALUE (0-199)
4279
ex = COll.lNH VALUE 10-639)
4280
EXIT --
4281 51 =OFFSET INTO REGEN BUFFER FOR BYTE OF INTEREST
4282
I
AH = MASK TO STRIP OFF THE SITS Of INTEREST
4283
CL = BITS TO SHIfT TO RIGHT JUSTIfY THE MASK IN AH
4284
I
DH = • BITS IN RESULT
4285
1--------------------------------------------------------
F452
4286 03 PROC NEAR
F452 53
4287 PUSH BX
1 SAVE BX D~ING OPERATION
F453 50
428S PUSH AX
1 WILL SAVE .u DURING OPERATION
4289
4290 1----- DETERMINE 1ST BYTE IN IDICATED ROW BY HULTIPlYING ROW VALUE BY 40
4291
BIT OF ROW DETERMINES EVEN/ODD. SO BYTESIROW
J----- (
lOW
4292
F454 B028
4293
HOV Al.40
F456 52
4294 PUSH OX
, SAVE ROW VALUE
F457 80E2FE
4295
.NO DL.OFEH
J
STRIP OFF DOD/EVEN BIT
F45A F6E2
4296
HUl
Ol
J AX HAS ADDRESS Of 1ST BYTE
4297
,
OF It-CICATEO ROW
F45C SA
4298 POP
OX
; RECOVER IT
F45D F6C201
4299
TEST Dl.l
; TEST FOR EVENIODD
F460 7403
4300
JZ I JUMP IF EVEN ROW
F462 050020
4301
'00
AX.2000H
I OFFSET TO LOCATION OF 000 ROWS
F465 4302
R4:
J EVEN_ROW
F465 8BFO
4303
HOV SI.AX
1 MOVE POINTER TO 51
F467 58
4304 POP AX ; RECOVER AL VALUE
F468 8BDI
4305
HOV
OX.CX
;
COLUMN VAlUE TO OX
4306
4307
1----- DETERMINE GRAPHICS HaDE CURRENTLY IN EFFECT
4308
4309
r""\
R'
1-------------- - --------------- ------ --------------------------.-
4310
; SET UP THE REGISTERS ACCORDING TO THE HOOE
4311
CH = I1ASK FOR LOW OF COLlR1H ADDRESS ( 7/3 FOR HIGH/NED RES)
4312 CL :::: • OF ADDRESS BITS IN COLUMN VALUE ( 312 FOR H/NI
4313
I
BL = HASK TO SElECT BITS FROM POINTED BYTE ISOH/COH fOR H/N)
4314
I
BH = NUMBER OF VAlID BITS IN POINTED BYTE ( 112 fOR HIH)
4315
1-- - --- - - -- - -------- - ------ - -- - ------ - - ---- -- - ------ -------- - -- --
4316
F46A BBC002
4317
I10V BX.2tOH
F46D B90203
431S
Mev CX.302H ; SET PARHS FOR MED RES
F470 803E490006
4319
CHP
CRT.HODE.6
F475 7206
4320
JC
.5
; HANOLE If MED ARES
F477 BB8001
4321
HOV BX.180H
F47A B90307
4322
HOV
CX.703H
; SET PARHS fOR HIGH RES
4323
4324
1----- DETERMINE BIT OFFSET IN BYTE FROM COLUHH MASK
4325
F47D
4326 RS:
F47D 22EA
4327
ANI)
CH.DL 1 ADDRESS OF PEL WITHIN BYTE TO CH
4328
4329
J ----- DETERMINE BYTE OFFSET FOR THIS LOCATION IN COlUHN
4330
r"'\
F47F 03EA
4331 SHO
DX.CL
; SHIFT BY CORRECT AMOUNT
F481 03F2
4332 .DO SI,OX I INCREMENT THE POINTER
F483 8AF7
4333
HOY
OH,SH ; GET THE • OF BITS- IN RESULT TO OH
4334
4335
1----- HULTIPL'f BH (VALID BITS IN BYTE) BY CH (BIT OFFSEll
433&
F485 ZAC9
4337
SUB CL.CL
; ZERO INTO STORAGE LOCATION
F487
'3]8
R6:
System BIOS 5-89