Intel 80287, 80286 manual Function. Partitioning

NUMERIC PROGRAMMING EXAMPLES

iAPX2Bb MACRO

ASSEMBLER

Calculate the

value of

10**ax

12: 11: 08

09/25/83

PAGE

LOC

OBJ

LINE

SOURCE

COCA

O'9EO

5.

-Fchs

ooce

D9Cl

60

n.

st( 1)

I

COPV power value in base two

DOCE

D96EFC

61

fIldcw

word ptr [bp-4J

Set new control word value

0001

D9FC

6 .

f'rndint

TOS

= I:

-inf

< I

<= X.

I

is an int~g~r

0003

8946FC

63

mav

word ptr [bp-4], ax

I

R~5tor~

original

rounding

control

0006

D9bEFC

6'

fidew

wOl'd ptr [bp-4J

-1.0. 51(2) '" I

0009

D9CA

65

Fxch

st(2)

I

TOS

.. X.

91(U

""

DaDa

08E2

66

hub

st, st(2)

TOS. F -..

X-I:

a

<..

TOS <

1. a

DODD

BB46FE

67

mov

ax, Cbp-2J

Restore

power

of

ten

OOEO

D9FD

68

flscale

TOS

... F/2: a

<.. TOS < 0.5

00E2

D9FO

6 .

f'2xml

TOS

'" 2**(F/21

-

1. 0

00E4

C9

70

l ... v.

I

Restore

stack

ODES

DEE1

71

fsubl'

st. steOl

J

Form

2**(F/2)

OOE7

Dcca

7 .

flmul

Form

2**F

00E9

C3

73

rot

j

OK to leave fmul running

7 .

get_power _10

75

endp

76

77

code

ends

78

en.

A8SEMBL V COMPLETE,

NO

WARNINGS,

NO ERRORS

iAPX28b MACRO

ASSEMBLER

Det~rmin~ TOS

r~gist~r

cont~nts

12: 12: 13

09/25/83

PAGE

SERtES-I11 iAPX28b MACRO ASSEMBLER XI08 ASSEMBLV OF MODULE TOS_STATUS

OBJECT MODULE PLACED IN : F3: TOS8T. OBJ

ASSEMBLER INVOKED BV:

ASM28b.86: F3: T09ST. AP2

LaC OBJ

0000

0000 09E5

0002 9BDFEO

0005 8AC4

0007 250740 OOOA COEC03 0000 OAC4 OOOF B400 0011 C3

LINE SOURCE

1 +1 $title("D~t~rmine TOS register contents")

2

3This subr.outine will return a value from 0-15in AX corres,ponding

4to the contents of 80287 T09. All re!listlH's are transparent and no

5errors are possible The return value corresponds to c3,c2,cl.cO

6of FXAM instruction.

7
8			tos_status
10•		pub lic
11	stack		stacks8g 6	) Allocate space on the stack
12
13
I.	code		se!lment	pub 1 ic
15			proc
16
17		fxam		) Get register contents status
18			a.
,.		fstsw		)	Get status
20		mov	OIl. ah		Put bit 10-8into bits 2-0
21		an.	al,4007h		Mask out bits c3,c2.c1.cO
22		,hr	ah,3	) Put bit c3 into bit 11
23			OIl. ah	J Put c3 into bit 3
2.		mov	ah.O	I	Clear return value

25ret

27	endp
28

	2.	code	ends
	30		end
ASSEMBLV COMPLETE,	NO WARNINGS,	NO	ERRORS

Fi!!~lrA 4-~~Flnllting-Point to ASCII Conversion Routine (Cont'd.l

Function. Partitioning

Three separate modules implement the conversion. Most of the work of the conversion is done in the module FLOATING_TO_ASCII. The other modules are provided separately, because they have a more general use. One of them, GET_POWER_IO, is also used by the ASCII to floating-point conver- sion routine. The other small module, TOS_STATUS, will identify what, if anything, is in the top of the numeric register stack.

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