dsp56000 Freescale Semiconductor, Inc, dsp56000 Datasheet - Page 45

• Manufacturer Part Number: dsp56000
• Description: 24-bit Digital Signal Processor Family Manual
• Manufacturer: Freescale Semiconductor, Inc

MOTOROLA
CASE I: IF A0 < $800000 (1/2), THEN ROUND DOWN (ADD NOTHING)
BEFORE ROUNDING
CASE II: IF A0 > $800000 (1/2), THEN ROUND UP (ADD 1 TO A1)
BEFORE ROUNDING
CASE III: IF A0 = $800000 (1/2), AND THE LSB OF A1 = 0,THEN ROUND DOWN (ADD NOTHING)
BEFORE ROUNDING
CASE IV: IF A0 = $800000 (1/2), AND THE LSB = 1, THEN ROUND UP (ADD 1 TO A1)
BEFORE ROUNDING
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XX . . XX XXX . . . XXX0100 011XXX . . . . XXX
XX . . XX XXX . . . XXX0100 1110XX . . . . XXX
XX . . XX XXX . . . XXX0100 10000 . . . . . . 000
XX . . XX XXX . . . XXX0101 10000 . . . . . . 000
*A0 is always clear; performed during RND, MPYR, MACR
A2
A2
A2
A2
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A1
A1
A1
A1
DATA REPRESENTATION AND ROUNDING
Freescale Semiconductor, Inc.
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Figure 3-10 Convergent Rounding
For More Information On This Product,
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1
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1
DATA ARITHMETIC LOGIC UNIT
Go to: www.freescale.com
A0
A0
A0
A0
0
0
0
0
AFTER ROUNDING
AFTER ROUNDING
AFTER ROUNDING
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AFTER ROUNDING
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XX . . XX XXX . . . XXX0100 000 . . . . . . . . 000
XX . . XX XXX . . . XXX0101 000 . . . . . . . . 000
XX . . XX XXX . . . XXX0100 000 . . . . . . . . 000
XX . . XX XXX . . . XXX0110 000 . . . . . . . . 000
A2
A2
A2
A2
48 47
48 47
48 47
48 47
A1
A1
A1
A1
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A0*
A0*
A0*
A0*
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