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Clock-cycle timings for Weitek coprocessors
The Weitek 3167 and 4167 coprocessors only implement the basic arithmetic functions (add, subtract, multiply,
divide, square root) in hardware; transcendental functions are implemented by means of a software library
supplied by Weitek which uses the basic hardware instructions to approximate the transcendental functions
(using polynomial and rational approximations). The clock cycle timings for the transcendental functions are
average values, since execution time can differ with the value of argument. The speed of transcendental functions
for the 4167 is estimated based on the numbers in weitek docs, from which this timing information has been
extracted.
| |
Single Precision |
Double Precision |
| |
3167 |
4167 |
3167 |
4167 |
| ABS |
3 |
2 |
3 |
2 |
| NEG |
6 |
2 |
6 |
2 |
| ADD |
6 |
2 |
6 |
2 |
| SUB |
6 |
2 |
6 |
2 |
| SUBR |
6 |
2 |
6 |
2 |
| MUL |
6 |
2 |
10 |
3 |
| DIVR |
38 |
17 |
66 |
31 |
| SQRT |
60 |
17 |
118 |
31 |
| SIN |
146 |
~50 |
292 |
~100 |
| COS |
140 |
~50 |
285 |
~100 |
| TAN |
188 |
~60 |
340 |
~110 |
| EXP |
179 |
~60 |
401 |
~130 |
| LOG |
171 |
~60 |
365 |
~120 |
| F --> ASCII |
1000 |
N/A |
1700 |
N/A * |
| ASCII --> F |
1100 |
N/A |
1800 |
N/A * |
* rough average of the timings given for different numeric formats by Weitek.
Note that these conversions routines do much more work than the FBLD and FBSTP instructions provided by the
80x87 coprocessors. FBLD and FBSTP are useful for conversion routines but quite a bit of additional code is
need for this purpose.
Information © Norbert Juffa, Karlsruhe, Germany [excerpt of COPRO16A.TXT]
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