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gate count 1625 number of cells 538 number of library cells 179 number of used cells 54 max fanin 17 max input capacitance 214 max internal fanout 34 critical path 0fF 2111 critical path 6fF 2497 |
Now an x8 drive strength is added for those functions where its size is not too big:
an2v0x8 an3v0x8 aoi21v0x8 nd2v0x8 nd2av0x8 nd2abv0x8 nd3v0x8 nr2v0x8 nr2av0x8 oai21v0x8 or2v0x8 or3v0x8 |
a total of 12 new cells.
The x8 cells give a 1.0% speed improvement at the cost of an area increase of 0.9%. The x8, x6, x4 and x3 drive strength usage is:
x3 x4 x6 x8
an2 0 0 0 2
aoi22 0 1 - -
cgi2 17 - - -
iv1 3 6 10 4
nd2a 0 0 1 0
nd4 1 - - -
nr2 1 0 1 0
nr2a 0 1 0 0
oai21 13 5 2 10
xaon21 1 - - -
xoon21 2 - - -
xor2 8 1 - -
+----+----+----+----+
TOTAL 46 14 14 16 |
17% of the cells have a drive strength bigger than x2. As before, the bulk of the x8 usage is with the oai21v0x8 cells.
The speed of the critical path is limited by the carry generator inverting cells, cgi2, which have a maximum drive strength of x3. The parallel critical path of oai21 cells has been buffered up so that it is faster than this one. This path though has some x8 drive strength cells which contribute to it being slightly faster than the previous experiments.
x 2 17 182
1 iv1v0x12 24 a->z 303 121
2 nr2v0x6 1 b->z 360 57
3 xoon21v0x3 1 b->z 455 95
4 xor2v0x3 1 b->z 540 85
5 cgi2v0x3 3 c->z 646 106
6 iv1v0x6 1 a->z 695 49
7 cgi2v0x3 3 c->z 793 98
8 iv1v0x4 1 a->z 848 55
9 cgi2v0x3 3 c->z 954 106
10 iv1v0x6 1 a->z 1002 48
11 cgi2v0x3 3 c->z 1107 105
12 iv1v0x6 1 a->z 1156 49
13 cgi2v0x3 3 c->z 1252 96
14 iv1v0x3 1 a->z 1315 63
15 cgi2v0x3 3 c->z 1422 107
16 iv1v0x6 1 a->z 1471 49
17 cgi2v0x3 4 c->z 1581 110
18 xnr3v1x2 1 b->z 1790 209
19 cgi2v0x3 2 c->z 1879 89
20 iv1v0x6 1 a->z 1928 49
21 cgi2v0x3 2 c->z 2016 88
22 iv1v0x6 1 a->z 2065 49
23 cgi2v0x3 2 c->z 2147 82
24 an2v0x8 2 b->z 2250 103
25 an2v0x8 2 b->z 2361 111
26 xaon21v0x3 0 a2->z 2497 136
r 15 |
| Table of synthesis results | |||||||
| critical path (ps) | gate count | cell count | porosity | library cells | used cells | ||
| synthesis 1 | 4279 | 1561 | 923 | 43% | 9 | 8 | basic inverters, NAND & NOR gates |
| synthesis 2 | 4236 | 1472 | 792 | 45% | 15 | 12 | AND & OR gates |
| synthesis 3 | 4157 | 1357 | 696 | 46% | 19 | 16 | AOI & OAI gates, 2/1 and 2/2 |
| synthesis 4 | 4157 | 1357 | 696 | 46% | 20 | 16 | mxi2 2-way inverting mux |
| synthesis 5 | 3983 | 1343 | 668 | 48% | 21 | 16 | cgi2 carry generator inverting |
| synthesis 6 | 3948 | 1352 | 668 | 48% | 28 | 18 | inverters with multiple drive strengths |
| synthesis 7 | 3061 | 1433 | 666 | 51% | 70 | 27 | x2 drive strengths for all functions |
| synthesis 8 | 3056 | 1456 | 666 | 52% | 70 | 30 | BOOG with x1 drive strengths |
| synthesis 9 | 2960 | 1476 | 666 | 53% | 70 | 32 | BOOG with x05 drive strengths |
| synthesis 10 | 2963 | 1480 | 666 | 53% | 76 | 34 | nd2a and nr2a cells |
| synthesis 11 | 2963 | 1480 | 666 | 53% | 79 | 34 | nd2ab type of 2-OR |
| CyHP library | 3778 | 1539 | 832 | 46% | 18 | 17 | Minimum size library |
| synthesis 12 | 2908 | 1362 | 553 | 54% | 91 | 38 | AND/OR into XOR/XNOR |
| synthesis 13 | 2893 | 1378 | 551 | 55% | 103 | 39 | aoi211, aoi31, oai211 & oai31 |
| synthesis 14 | 2931 | 1400 | 562 | 55% | 104 | 38 | 3-XOR gate, 1/2 stage delays |
| synthesis 15 | 2886 | 1390 | 536 | 56% | 109 | 40 | 3-XOR/XNOR gates as 2×2-I/P gates |
| synthesis 16 | 2665 | 1514 | 538 | 60% | 136 | 46 | x3 drive strength cells |
| synthesis 17 | 2567 | 1571 | 540 | 61% | 155 | 49 | x4 drive strength cells |
| synthesis 18 | 2523 | 1611 | 540 | 62% | 167 | 49 | x6 drive strength cells |
| synthesis 19 | 2497 | 1625 | 538 | 62% | 179 | 54 | x8 drive strength cells |
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