Freescale Semiconductor, Inc.
The table instruction is executed with the following bit pattern in Dx:
31
16
15
1
0
0
NOT USED
0
1
0
0
0
1
1
1
0
0
0
0
0
0
Table Entry Offset
Interpolation Fraction
Dx [8:15] = $A3 = 163
Dx [0:7] = $80 = 128
Using this information, the table instruction calculates dependent variable Y:
Y = 1669 + (128 (1679 – 1669)) / 256 = 1674
5.3.4.2 TABLE EXAMPLE 2: COMPRESSED TABLE. In Example 2 (see Figure 5-8), the
data from Example 1 has been compressed by limiting the maximum value of the
independent variable. Instead of the range 0 ≤ X = 65535, X is limited to 0 ≤ X ≤ 1023.
The table has been compressed to only five entries, but up to 256 levels of interpolation
are allowed between entries.
Y
256
512
786
1024
X
INDEPENDENT VARIABLE
Figure 5-8. Table Example 2
NOTE
Extreme table compression with many levels of interpolation is
possible only with highly linear functions. The table entries
within the range of interest are listed in Table 5-14.
MOTOROLA
MC68340 USER’S MANUAL
5- 31
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