Intel 80287, 80286 manual Data Formats

Models: 80287 80286

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OVERVIEW OF NUMERIC PROCESSING

__ INCREASING SIGNIFICANCE

WORD INTEGER lSi MAGNITUDE I(TWO'SCOMPLEMENT)

 

 

 

15

0

 

 

 

 

 

SHORT INTEGER I~I

MAGNITUDE

 

 

(TWO'S

 

 

L. ..1."--__________

COMPLEMENT)

 

 

31

 

 

 

 

 

I

 

II

 

 

 

M_A_G_N_IT_U_D_E

LONG INTEGER LS..I"--__"--

 

 

 

 

(TWO'S

 

 

 

 

- . I COMPLEMENT)

 

U

 

 

 

 

 

0

PACKED DECIMAL

 

 

 

 

 

MAGNITUDE

 

 

d17 d 6 d '5

d

'

4 d '3 d '2

d 11 d10 d g dB d 7 d6 d 5

d 4 d 3 d 2 d , dO

 

 

 

 

'

 

 

 

 

 

79

72

 

 

 

 

 

SHORT REAL

 

 

 

 

 

 

 

LONG REAL

S

BIASED

 

 

 

SIGNIFICAND

 

EXPONENT

 

 

 

 

 

 

 

 

 

 

 

 

63

 

 

 

1 !

 

o

 

 

 

 

 

 

 

TEMPORARY REAL

LIS..lI"--__E_X_~_~_~_i_~_T__..II~I~I

S_IG_N_1_F_IC_A_N_D

~

 

79

 

6463~

 

0

NOTES:

5 Sign bit (0 = positive, 1 ~ negative)

dn Decimal digit (two per byte)

XBits have no significance; 80287 Ignores when loading, zeros when storing.

Position of implicit binary point

1Integer bit of signi1icand: stored in temporary real, implicit (always 1) in short and long real Exponent Bias (normalized values):

Short Real: .127 (7FH)

Long Real: 1023 (3FFH)

Temporary Real:. 16383 (3FFFH)

G30108

Figure 1-9. Data Formats

1-16

Page 368
Image 368
Intel 80287, 80286 manual Data Formats