Intel 80287, 80286 manual 4BB

NUMERIC PROGRAMMING EXAMPLES

iAPX286 MACRO ASSEMBLER

LOC ODJ

0153 B9040F

0156 BBOI00

0159 BD7EOC

DISC BCDS

015E eEeD

0160 Fe

0161 B02B

0163 F6(:201

0166 7402

0168 802D

016A

016A AA

0168 BOE2FE

016E 98

016F

016F BA62FO

0172 BAC4

0174 D2EB

0176 22C5

0178 7516

017A BAC4

al7e 22C5 017E 7518

0180 4E

0181 79EC

0183 0030

0185 AA

01B6 43

0187 EU6

0189

0189 BA62FO alBC 8AC4 018E 02E8

0190

0190 0430

0192 AA

0193 BAC4

0195 22C5

0197 43

80287

Floatlnll-Paint to IS-Digit ASCII Conve,.si!)"

10: 12: 38

09/25/83 PAQE

LINE

SOURCE

416

cx.Of04h

I

Set

shift count .nd mlillsk

417

bll,l

S. t initial sin of ASCII . hld for aign

418

di. ~trinIlJt,.

Get .. ddre .. of start of ASCII string

419

ax. ds

I

CoPu

ds

to es

4.0

mov

421

cld

.. I, '+'

Set .. utoinere.ent mode

4.2

mov

I C ....r sign fhld

423

tnt

dl.I1INUS

Look 'or ne.ative v .. lue

424

JI

positive_result

4••

426

al. ' - '

4.7

posi tive_resul t:

4.B

429

430

stosb

I

Bump

string pointer past

sign

431

.and

dl. not MINUS

I

Turn

off

sign

bit

43.

flilait

I

W,.it

for

fbstp

to

finish

433

434

4,.

ah:

BCD byte value in use

430

al:

ASCII

character

v.alue

437

dx:

Return

value

438

eh:

BCD mask. Ofh

439

c1:

BCD shift count . 4

440

bx:

ASCII

string field

width

441

si:

BCD field

index

44.

di:

ASCII

strihg field

pointer

443

ds •• s:

ASCII string segment ba.e

444

,

44.

Remove

leading

from the

number.

440

447sk ip_l e .. di ng_1 erolt.:

449	mo.	ah. bed_buteCsil		I	get	BCD	byte
••0		a!. ah			Cop"	value
451	.hr	0111.	cl	I	Get	high	ordar	digit
4 2	and	0111.	eh	I	Set	lero	flag
4""	JU	enter _odd			Exit loop if leading non ze1'O found
4'4
...	mo.	0111. ah			Get	BCD bute again
..0	and	al, eh			Get	low	order	digit
457	JU	ente1' _even			Exit loop if non IBro digit found
458
459	dec	5i		I	Decrlment BCD			indu
400	Jno	skip_lead ing_IB1'oes
401
40.	The	significand lIIas all
40'
40.	mov	al. '0'		I	Set	initial
'05	stosb
400	inc	bx			Bump	st1'ing length

407Jmp short exit_1II1th_value

46B

469NOIII elpand the BCD stTing into digit per byte values 0-9 .

• 70

.71.
	mo.	ah. bcd_byte[siJ	Get	BCD	tU,Ite
47'
474	mov	0111. ah	get
'75	'hr	0111. cl		high	order digit
.70
'77	enter _odd:
.7B	add		, Convert
.79		al. '0'			to ASCII
'BO	stosb		Put digit into ASCII string
481	mo.	0111. ah	Get 10. order digit
4B.	and	al, ch
4B,	inc	b,	Dump	field size counte"
4B4

0198		4B5
0198	0430	.80
		4B7
Ol9A	AA	4BB
0198	43	489
019C	4E	490
019D	79EA	491
		49.
		49'
		494
019F		495
019F BB7EaA		496
		497
01A2	891D	49B
VIA.. aa\..,:		..;r;;
01A6 E9BOFE		500
		001
		50.
		50'
		504
ASSEMIILY··COMPLETE.		NO ·WARNINGS.

enter _even:
add	011. '0'	Convert to		ASCII
stosb	b,	Put digit		into	ASCI I area
inc		Dump	field	size	counter
dec	.,	00 to	next	DCD	byte
In.	digit_loop

,Conversion complete. Set the string size IillJld remainder. ex it_lilith_value:

	6i . slzeJtr
	lIIoT'd ptr [dil, bx
	.."'.;,,
Jmp	ex i tJroc

floating_to_... ciiendp

codeends end

NO ERRORS

Figure 4-6. Floating-Point to ASCII Conversion Routine (Cont'd.)

4-12