关于lib的分析
工艺库分为逻辑库和物理库两类。
逻辑库包括DC综合所需要逻辑信息，时延信息，各单元的面积大小、功耗，互连线RC模型以及运行条件等。逻辑库是一个.lib文本文件，它经库编译器（LC）生成DC可以直接使用的以.db为扩展名的二进制文件。本节所说明的库信息是指逻辑库的库信息。
物理库描述与版图设计相关的单元的物理特性(如：单元的长和宽、层次结构、、天线规则、工艺设计规则、单元方向等)。物理库与逻辑库相对应，即在逻辑库中描述的单元，对应在物理库中也必须有这个单元的物理描述。物理库是以.plib为扩展名的文本文件，经库编译器（LC）生成DC可以直接使用的以.pdb为扩展名的二进制文件。
逻辑库由库分组、库级属性、环境描述和单元描述几个部分组成。下面分别进行说明。
(1) 库分组
库分组定义了库的名字和库的具体描述，建议库文件名与库名一致。库分组描述列出如下：
library(mylib) {
……
<library description>
……
}
(2) 库级属性
库级属性描述了整个库的特性，包括工艺类型、日期、版本和应用于整个库的默认值。库级属性描述列出如下：
library(mylib) {
technology(cmos);
delay_model :table_lookup;
date :“Feb 29,2000”;
revision :“1.0”;
current_unit :“1A”；
time_unit :“1ns”;
voltage_unit :“1V”;
pulling_resistance_unit :“1kohm”;
capacitive_load_unit(1.0,pf);
default_inout_pin_cap :1.5;
default_input_pin_cap :1.0;
default_output_pin_cap :0.0;
default_max_fanout :10.0;
default_max_transition :3.0;
default_operating_conditions :NOMINAL
in_place_swap_mode :match_footprint;
……
}
(3) 环境描述
环境描述定义了模化参数，如：温度、电压和制程，这些模化参数由比例因子（scaling factors）、时序范围模型（timing range model）和运行条件（operation conditions）组成。另外，环境描述还包含线负载模型（wire-load model），这个模型被DC用来估算互连线延迟。
比例因子
比例因子或K 因子用于表示由于PVT（工艺、电压、温度）的变化而引起的延时变化的缩放倍数，部分比例因子列出如下
k_process_fall_transition :1.0;
k_process_rise_transition :1.2
k_process_fall_propation :0.4;
k_process_rise_propagation :0.4;
k_temp_fall_transition :0.03;
k_temp_rise_transition :0.04;
k_temp_fall_propagation :1.2;
k_temp_rise_propagation :1.24;
k_volt_fall_transition :0.02;
k_volt_rise_transition :0.5;
k_volt_fall_propagation :0.9;
k_volt_rise_propagation :0.85;
运行条件
运行条件定义了用于综合时所采用的工艺、温度、电压条件和互连线RC 模型。如果只有一套某一运行条件的工艺库文件，而在综合时却指定了其它运行条件，DC将使用比例因子来修正库单元相应的时间参数。
下面列出几个典型的运行条件：
operating_conditions ( worst ) {
process : 1 ;
voltage : 1.62 ;
temperature : 125 ;
}
operating_conditions ( typical ) {
process : 1 ;
voltage : 1.8 ;
temperature : 25 ;
}
operating_conditions ( best ) {
process : 1 ;
voltage : 1.98 ;
temperature : 0 ;
}
tree_type定义了互连线的RC模型，DC使用这个模型来计算互连线延时。worst_case_tree是指将所有互连线电容集中放在负载引脚一端的极端情况，这种情况使输入单元承担了全部的线电容和线电阻。typical_tree模型是指所有负载引脚均匀分担来自驱动引脚的互连线电容、电阻的情况。best_case_tree模型是指将所有互连线电容集中放在驱动引脚一端的极端情况，此时负载引脚只有连线电容而没有连线电阻。
线负载模型
线负载(wire_load)是根据特定工艺，基于不同设计规模和设计方法，从实际版图中得出的互连线RC时延经验模型，它被DC在综合时用来估算互连线时延的信息。通常，每一个工艺库中都有几种线负载模型，它们分别适用于不同规模的逻辑设计。由于对于不同的设计互连线时延差别也较大，所以建议读者根据自己的逻辑设计特点建立自己的线负载RC模型。
线负载模型定义了单位长度的电容、电阻和面积，扇出负载与线长的对应关系(fanout_length),线性近似斜率(slope)。当扇出负载超出定义在fanout_length上的最大值时，互连线长度可以用斜率slop值根据已有的fanout_length线性化近似得到。wire_load定义列出如下：
wire_load ( "reference_area_2500000" ) {
resistance : 0.00038 ;
capacitance : 0.00025 ;
area : 0.00000 ;
slope : 57.0571 ;
fanout_length ( 1,32.381 ) ;
fanout_length ( 2,80 ) ;
fanout_length ( 3,119.048 ) ;
fanout_length ( 4,175.714 ) ;
fanout_length ( 5,219.048 ) ;
fanout_length ( 6,259.524 ) ;
fanout_length ( 7,288.571 ) ;
fanout_length ( 8,297.143 ) ;
fanout_length ( 9,302.381 ) ;
fanout_length ( 10,328.095 ) ;
fanout_length ( 11,428.571 ) ;
fanout_length ( 12,442.857 ) ;
fanout_length ( 13,447.619 ) ;
fanout_length ( 14,459.048 ) ;
fanout_length ( 15,532.381 ) ;
fanout_length ( 16,659.524 ) ;
fanout_length ( 17,801.905 ) ;
fanout_length ( 18,901.905 ) ;
fanout_length ( 19,953.81 ) ;
fanout_length ( 20,990.952 ) ;
}
(4) 单元描述
在库中的每个单元都有一个单元描述。一个单元的描述列出如下：
cell ( AND2HD1X ) {
area : 13.306;
cell_leakage_power : 0.540865 ;
cell_footprint : and2 ;
pin ( A ) {
direction : input ;
capacitance : 0.00294286 ;
rise_capacitance : 0.00292701 ;
fall_capacitance : 0.00294286 ;
}
pin ( B ) {
direction : input ;
capacitance : 0.00314674 ;
rise_capacitance : 0.00314674 ;
fall_capacitance : 0.00314291 ;
}
pin ( Z ) {
direction : output ;
capacitance : 0 ;
rise_capacitance : 0 ;
fall_capacitance : 0 ;
max_capacitance : 0.226562 ;
function : "A&B" ;
timing ( ) {
related_pin : "A" ;
timing_sense : positive_unate ;
cell_rise ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.058498, 0.069378, 0.5596, 1.20027, 1.60813, 2.4304" ) ;
values ( \
"0.132658, 0.13572, 0.184429, 0.210828, 0.216418, 0.220603", \
"0.234715, 0.237675, 0.290719, 0.321558, 0.333297, 0.344568", \
"0.792694, 0.795275, 0.850812, 0.882457, 0.893892, 0.909202", \
"1.53602, 1.53849, 1.59362, 1.62571, 1.63737, 1.65246", \
"2.00032, 2.00245, 2.05805, 2.09008, 2.10162, 2.1164", \
"2.9285, 2.93095, 2.98578, 3.01854, 3.03025, 3.04543") ;
}
rise_transition ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.058498, 0.069378, 0.5596, 1.20027, 1.60813, 2.4304" ) ;
values ( \
"0.0864, 0.0864, 0.0928, 0.1056, 0.12, 0.1264", \
"0.2552, 0.256, 0.2648, 0.2728, 0.2808, 0.2944", \
"1.4344, 1.4344, 1.4352, 1.4368, 1.4384, 1.4432", \
"3.0232, 3.0232, 3.0256, 3.0256, 3.0272, 3.028", \
"4.0184, 4.02, 4.02, 4.0192, 4.0224, 4.024", \
"6.0096, 6.0104, 6.0104, 6.008, 6.0144, 6.016") ;
}
cell_fall ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.052446, 0.0824, 0.5592, 1.20013, 1.60613, 2.41933" ) ;
values ( \
"0.143626, 0.152282, 0.266736, 0.366397, 0.418983, 0.513028", \
"0.221282, 0.228051, 0.352769, 0.458738, 0.514917, 0.616055", \
"0.586788, 0.59427, 0.719505, 0.829946, 0.888611, 0.994143", \
"1.06431, 1.07178, 1.19716, 1.30821, 1.36643, 1.47228", \
"1.36312, 1.37058, 1.49612, 1.60655, 1.66504, 1.77053", \
"1.96028, 1.96777, 2.09331, 2.20336, 2.26244, 2.368") ;
}
fall_transition ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.052446, 0.0824, 0.5592, 1.20013, 1.60613, 2.41933" ) ;
values ( \
"0.071987, 0.071488, 0.0896, 0.1032, 0.1096, 0.124", \
"0.1736, 0.1768, 0.1832, 0.2024, 0.2096, 0.2208", \
"0.832, 0.8312, 0.8352, 0.84, 0.8424, 0.8496", \
"1.744, 1.744, 1.7464, 1.7472, 1.7504, 1.7512", \
"2.316, 2.316, 2.316, 2.3184, 2.3192, 2.3208", \
"3.46, 3.46, 3.4608, 3.4624, 3.4616, 3.4664") ;
}
}
timing ( ) {
related_pin : "B" ;
timing_sense : positive_unate ;
cell_rise ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.060154, 0.074798, 0.560133, 1.20013, 1.60813, 2.43027" ) ;
values ( \
"0.128169, 0.127024, 0.199365, 0.238135, 0.25307, 0.268721", \
"0.229865, 0.228965, 0.304938, 0.347712, 0.365036, 0.389908", \
"0.787456, 0.786799, 0.863978, 0.907405, 0.925125, 0.951696", \
"1.53077, 1.52981, 1.60608, 1.65, 1.66857, 1.6947", \
"1.99502, 1.9936, 2.07113, 2.11542, 2.13293, 2.15915", \
"2.92294, 2.92204, 2.99977, 3.04354, 3.06143, 3.0869") ;
}
rise_transition ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.060154, 0.074798, 0.560133, 1.20013, 1.60813, 2.43027" ) ;
values ( \
"0.0864, 0.079992, 0.0936, 0.1152, 0.1152, 0.1288", \
"0.2544, 0.2552, 0.2656, 0.2728, 0.2784, 0.2944", \
"1.4344, 1.4328, 1.4344, 1.436, 1.4368, 1.4424", \
"3.0248, 3.0248, 3.0264, 3.0272, 3.0272, 3.0304", \
"4.0184, 4.0208, 4.0216, 4.0208, 4.0232, 4.0248", \
"6.0072, 6.0104, 6.0128, 6.0104, 6.0112, 6.0144") ;
}
cell_fall ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.052451, 0.0824, 0.559333, 1.20013, 1.6064, 2.41933" ) ;
values ( \
"0.126639, 0.132641, 0.242935, 0.329603, 0.376793, 0.460927", \
"0.2063, 0.213754, 0.327784, 0.424606, 0.47516, 0.564781", \
"0.570069, 0.577186, 0.694979, 0.796279, 0.848888, 0.944099", \
"1.0475, 1.0546, 1.17276, 1.27353, 1.3264, 1.42242", \
"1.3462, 1.35294, 1.47096, 1.57188, 1.62489, 1.72057", \
"1.94298, 1.95042, 2.06831, 2.16854, 2.22243, 2.31789") ;
}
fall_transition ( delay_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.052451, 0.0824, 0.559333, 1.20013, 1.6064, 2.41933" ) ;
values ( \
"0.075245, 0.072279, 0.0816, 0.1112, 0.1152, 0.1224", \
"0.172, 0.1712, 0.1832, 0.196, 0.2064, 0.2224", \
"0.8304, 0.8312, 0.8336, 0.8392, 0.8416, 0.8512", \
"1.7424, 1.7448, 1.744, 1.7488, 1.7496, 1.752", \
"2.3152, 2.3168, 2.316, 2.3184, 2.3192, 2.3208", \
"3.4592, 3.4592, 3.46, 3.46, 3.464, 3.4656") ;
}
}
internal_power ( ) {
related_pin : "A" ;
rise_power ( energy_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.058498, 0.069378, 0.5596, 1.20027, 1.60813, 2.4304" ) ;
values ( \
"0.013386, 0.013365, 0.014318, 0.017374, 0.019457, 0.024357", \
"0.013555, 0.013516, 0.014163, 0.016746, 0.018669, 0.02311", \
"0.013912, 0.01384, 0.014309, 0.016664, 0.018504, 0.02262", \
"0.013991, 0.013899, 0.014389, 0.016764, 0.018596, 0.022649", \
"0.01401, 0.013914, 0.014412, 0.0168, 0.018626, 0.022675", \
"0.014019, 0.013926, 0.014422, 0.016819, 0.01866, 0.022701") ;
}
fall_power ( energy_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.052446, 0.0824, 0.5592, 1.20013, 1.60613, 2.41933" ) ;
values ( \
"0.022462, 0.022574, 0.025149, 0.029088, 0.031833, 0.0375", \
"0.023736, 0.023, 0.024594, 0.028132, 0.030562, 0.03568", \
"0.023918, 0.023266, 0.024768, 0.027961, 0.030185, 0.034954", \
"0.023997, 0.023336, 0.024856, 0.028046, 0.030268, 0.034931", \
"0.024022, 0.023361, 0.024884, 0.028074, 0.030299, 0.034958", \
"0.024049, 0.023398, 0.024903, 0.028107, 0.030327, 0.034984") ;
}
}
internal_power ( ) {
related_pin : "B" ;
rise_power ( energy_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.060154, 0.074798, 0.560133, 1.20013, 1.60813, 2.43027" ) ;
values ( \
"0.013149, 0.013103, 0.015064, 0.018038, 0.020512, 0.025301", \
"0.013259, 0.013487, 0.014353, 0.017285, 0.01934, 0.023808", \
"0.01362, 0.013838, 0.014642, 0.017174, 0.019046, 0.023158", \
"0.013688, 0.013907, 0.014718, 0.017263, 0.019125, 0.023166", \
"0.013704, 0.013913, 0.014749, 0.017295, 0.019155, 0.023183", \
"0.013704, 0.013933, 0.014773, 0.017329, 0.019187, 0.023211") ;
}
fall_power ( energy_template_6x6 ) {
index_1 ( "0.001, 0.02, 0.14, 0.3, 0.4, 0.6" ) ;
index_2 ( "0.052451, 0.0824, 0.559333, 1.20013, 1.6064, 2.41933" ) ;
values ( \
"0.018949, 0.018661, 0.022518, 0.02613, 0.028693, 0.034174", \
"0.020822, 0.020238, 0.021849, 0.025168, 0.027458, 0.032409", \
"0.02103, 0.02051, 0.021907, 0.025016, 0.027147, 0.03174", \
"0.021056, 0.02054, 0.021934, 0.025052, 0.02718, 0.031698", \
"0.021064, 0.020545, 0.021947, 0.025056, 0.027189, 0.031705", \
"0.021081, 0.020551, 0.02196, 0.025062, 0.027197, 0.031702") ;
}
}
}
}
