IBM PC CONVERTIBLE Technical Reference page 129

06F4 E9 016F R
06F7
06F7
06F7 80 E3 03
06FA 8A C3
06FC 51
06FD B9 0003
0700
0700 DO EO
0702 DO EO
0704 OA 08
0706 E2 F8
0708 8A FB
070A 59
070B C3
070C
070C
070C 52
0700 BA 8000
0710
0710 DO E8
0712 01 DA
0714 01 FA
0716
73 F8
0718
8B C2
071A
5A
071B e3
071C
D71C
071C 8A 24
071E
8A 44 01
0721 B9 COOO
0724 B2 00
0726
0726 85 Cl
0728 F8
0729 74 01
072B F9
072C DO 02
072E 01 E9
0730 01 E9
0732 73 F2
0734 88 56 00
JMP V IDEO_RETURN ALL DONE
GRAPHICS_READ ENDP
--------
-
--
- -
- -
-
--
-
- -
- - -- -- - - -- -
-
- -- - - - - - - -
- -
-- - -
--
-- ---
EXPAND_MED_COLOR - S19
THIS ROUTINE EXPANDS THE LOW 2 BITS IN BL TO
FILL THE ENTIRE BX REGISTER
ENTRY
BL
=
COLOR TO BE US ED ( LOW 2 BITS )
EXIT
BX
=
COLOR TO BE USED ( 8 REPLICATIONS OF THE
2 COLOR BITS )
--
--
---
---
-- - -
-
- - -
- - -
-- -
- - -
- - - -
- -
- - - -
- -
- - - - -
--
- - - - - -- -
--
S19 PROC NEAR
AND BL,3 ISOLATE THE COLOR BITS
MOV AL,BL COPY TO AL
PUSH CX SAVE REGISTER
MOV CX,3 NUMBER OF TIMES TO DO THIS
S20:
SAL AL,1
SAL AL,1 LEFT SHI FT BY 2
OR BL,AL ANOTHER COLOR VERS ION INTO BL
LOOP S20 FI LL ALL OF BL
MOV BH, BL
FILL UPPER PORTION
POP CX REGISTER BACK
RET ALL DONE
519 ENDP
EXPAND_BYTE - 521
521
THIS ROUTINE TAKES THE BYTE IN AL AND DOUBLES
ALL OF THE BITS, TURNING THE 8 BITS INTO
16 BITS. THE RESULT IS LEFT IN AX
PROC NEAR
PUSH OX
SAVE REGISTER
MOV DX ,8000H
BIT TO TERMINATE LOOP
DBLBIT4:
SHR AL,1
LOW ORDER BIT TO CARRY FLAG
RCR DX,1
FROM CARRY TO HIGH OF RESULT
SAR DX,1
DBL HIGH ORDER BIT -SIGN EXT
JNB DBLBIT4 TERM WHEN BIT SHIFTED OUT
MOV AX,DX PUT RESULT I NTO AX
POP DX RESTORE REGISTER
RET RETURN
521 ENDP
MED_READ_BYTE - S23
ENTRY
EXIT
523
THIS ROUTINE WILL TAKE 2 BYTES FROM THE REGEN
BUFFER, COMPARE AGAINST THE CURRENT FOREGROUND
COLOR, AND PLACE THE CORRESPONDING ON/OFF BIT
PATTERN INTO THE CURRENT POSITION IN THE SAVE
AREA
SI,DS
=
POINTER TO REGEN AREA OF INTEREST
BX
=
EXPANDED FOREGROUND COLOR
BP
=
POINTER TO SAVE AREA
BP IS INCREMENT AFTER SAVE
PROC NEAR
MOV AH, [SIJ
GET FI RST BYTE
MOV AL, [SI+IJ
GET SECOND BYTE
MOV CX,OCOOOH
2 BIT MASK TO TEST ENTRIES
MOV DL,O
RESULT REGISTER
S24 :
TEST AX, ex IS THIS SECTION BACKGROUND?
CLC CLEAR CARRY
JZ S25 I F ZERO, IT IS BACKGROUND
STC WASN'T, SO SET CARRY
S25 : RCL DL,1
MOVE THAT BIT INTO RESULT
SHR eX,1
SHR eX,1
MOVE MASK RIGHT BY 2 BITS
JNC 524
AGAI N [F MASK NOT FALL OUT
MOV [BPJ ,DL
STORE RESULT IN SAVE AREA
2-104 ROM BIOS