MC68EC040RC25A Freescale Semiconductor, MC68EC040RC25A Datasheet - Page 255

• Manufacturer Part Number: MC68EC040RC25A
• Description: IC MPU 32BIT 25MHZ 179-PGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68EC040RC25A

• Processor Type: M680x0 32-Bit
• Speed: 25MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 179-PGA
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -

9.4 COMPUTATIONAL ACCURACY
Whenever an attempt is made to represent a real number in a binary format of finite
precision, there is a possibility that the number can not be represented exactly. This is
commonly referred to as a round-off error. Furthermore, when two inexact numbers are
used in a calculation, the error present in each number is reflected, and possibly
aggravated, in the result. All FPU calculations use an intermediate result. When the
MC68040 performs an operation, the calculation is carried out using extended-precision
inputs, and the intermediate result is calculated as if to produce infinite precision. After the
calculation is complete, the intermediate result is rounded to the selected precision and
stored in the destination.
The FPCR encodings provide emulation for devices that only support single and double
precision. The execution speed of all instructions is the same whether using single- or
double-precision rounding. When using these two forced rounding precisions, the
MOTOROLA
Data Type
+ In-Range
–In-Range
+ Zero
–Zero
Infinity
SNAN
NAN
Sign
Explicit Integer Bit
Biased Exponent Format Maximum
Mantissa
Representation of Mantissa
Maximum Positive Normalized
Minimum Positive Normalized
Minimum Positive Denormalized
Nonsignaling
Signaling
Nonzero Bit Pattern Created by User
Mantissa When Created by FPCP
Table 9-6. Packed Decimal Real Format Summary
SM
0/1
0/1
0/1
0
1
1
0
Freescale Semiconductor, Inc.
0/1
0/1
0/1
0/1
SE
For More Information On This Product,
1
1
1
Table 9-5. Extended-Precision Real
Format Summary (Continued)
Y
1
1
1
X
X
X
X
Go to: www.freescale.com
M68040 USER’S MANUAL
Approximate Ranges
Y
1
1
1
X
X
X
X
$000–$999
$000–$999
$000–$999
$000–$999
NANs
Exponent
3-Digit
$FFF
$FFF
$FFF
$XXX0–$XXX9
$XXX0–$XXX9
1.11111…1111
32767 ($7FFF)
Integer
$XXXX
$XXXX
$XXXX
x.1xxxx…xxxx
x.0xxxx…xxxx
x.xxxxx…xxxx
3.7
1-Digit
$XXX0
$XXX0
1.7 10 –4932
1.2
Don’t Care
Don’t Care
Nonzero
10 –4951
10 4932
$00…01–$99…99
$00…01–$99…99
16-Digit Fraction
$00…00
Nonzero
Nonzero
$00…00
$00…00
9- 11