MOTOROLA
DSP96002 USER’S MANUAL
B-115
B.1.46
Evaluation of LOG(x)
Floating-point evaluation of log
2
(x) can be performed by representing x as s*(2**e) where s is the signifi-
cand and e is the unbiased exponent. Then, log
2
(s*(2**e)) = log
2
(s) + e. After extracting the significand s,
log
2
(s) can be evaluated with a polynomial. By adding the unbiased exponent, log
2
(x) results. Various
execution speeds and accuracies may be determined by using different order polynomials.
page 132,60,1,1
org x:0
polyc
dc 0.6681523e-02 ;**8
dc -0.6736254e-01 ;**7
dc 0.200 ;**6
dc -0.300 ;**5
dc -0.400 ;**4
dc 0.201 ;**3
dc -0.501 ;**2
dc 0.601 ;**1
dc -0.301 ;**0
org p:$100
;
; calculate d2=log2(d0)
;
Program
ICycles
Words
getexp d0,d7 #polyc,r0 2 2
fgetman d0,d0 1 1
fclr d2 x:(r0)+,d1.s 1 1
do #9,_log2sig 2 3
fmpy.x d2,d0,d2 1 1
fadd.x d1,d2 x:(r0)+,d1.s 1 1
_log2sig
float.x d7 1 1
fadd.s d7,d2 1 1
--- ---
Totals: 10 27
Summary of Contents for DSP96002
Page 3: ...1 2 DSP96002 USER S MANUAL MOTOROLA ...
Page 38: ...MOTOROLA DSP96002 USER S MANUAL 3 15 Figure 3 4 Modulo Arithmetic Unit Block Diagram ...
Page 39: ...3 16 DSP96002 USER S MANUAL MOTOROLA ...
Page 53: ...4 14 DSP96002 USER S MANUAL MOTOROLA ...
Page 76: ...MOTOROLA DSP96002 USER S MANUAL 5 23 Figure 5 8 Address Modifier Summary ...
Page 86: ...6 10 DSP96002 USER S MANUAL MOTOROLA ...
Page 101: ...MOTOROLA DSP96002 USER S MANUAL 7 15 Figure 7 9 HI Block Diagram One Port ...
Page 140: ...7 54 DSP96002 USER S MANUAL MOTOROLA ...
Page 166: ...9 10 DSP96002 USER S MANUAL MOTOROLA ...
Page 181: ...MOTOROLA DSP96002 USER S MANUAL 10 15 Figure 10 8 Program Address Bus FIFO ...
Page 337: ...MOTOROLA DSP96002 USER S MANUAL A 149 ...
Page 404: ...A 216 DSP96002 USER S MANUAL MOTOROLA PC xxxx D ...
Page 460: ...A 272 DSP96002 USER S MANUAL MOTOROLA SIOP Not affected ...
Page 484: ...A 296 DSP96002 USER S MANUAL MOTOROLA SSH PC SSL SR SP 1 SP ...
Page 519: ...MOTOROLA DSP96002 USER S MANUAL A 331 ...
Page 718: ...MOTOROLA DSP96002 USER S MANUAL B 199 ...
Page 871: ... MOTOROLA INC 1994 MOTOROLA TECHNICAL DATA SEMICONDUCTOR M Addendum ...
Page 888: ...MOTOROLA INDEX 1 INDEX ...
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