[Docs] Added Syntax Coverage Draft

Added documentation which describes the set of SDC syntax we are hoping
to support for this test suite.

This is a first draft and is subject to review.

Author: AlexandreSinger

docs/syntax/README.md

@@ -0,0 +1,167 @@
+# SDC Syntax
+
+## Timing Constraints
+
+### create_clock
+
+```
+create_clock -period <float>
+            (-name <string>)?
+            (-waveform {<float> <float>})?
+            (-add)?
+            (<pin_list>)?
+```
+
+### create_generated_clock
+
+```
+create_generated_clock (-name <string>)?
+                        -source <pin>
+                       (-master_clock <clock>)?
+                       (-divide_by <float>)?
+                       (-multiply_by <float>)?
+                       (-add)?
+                       <pin_list>
+```
+
+Note: There are other options. Should confirm if we want to support them.
+
+### set_clock_groups
+
+```
+set_clock_groups (-name <string>)?
+                 (-logically_exclusive)?
+                 (-physically_exclusive)?
+                 (-asynchronous)?
+                 (-allow_paths)?
+                 -group <clocks>
+```
+
+Note: VTR supports a flag called "-exclusive". Should check if we want this or not.
+
+### set_false_path
+
+```
+set_false_path (-setup)?
+               (-hold)?
+               (-rise)?
+               (-fall)?
+               (-from <from_list>)?
+               (-to <to_list>)?
+               (-through <through_list>)?
+```
+
+Note: There are some extra to discuss.
+
+### set_max_delay
+
+```
+set_max_delay (-rise)?
+              (-fall)?
+              (-from <from_list>)?
+              (-to <to_list>)?
+              (-through <through_list>)?
+              <delay: float>
+```
+
+### set_min_delay
+
+```
+set_min_delay (-rise)?
+              (-fall)?
+              (-from <from_list>)?
+              (-to <to_list>)?
+              (-through <through_list>)?
+              <delay: float>
+```
+
+### set_multicycle_path
+
+```
+set_multicycle_path (-setup)?
+                    (-hold)?
+                    (-rise)?
+                    (-fall)?
+                    (-from <from_list>)?
+                    (-to <to_list>)?
+                    <path_multiplier: float>
+```
+
+### set_input_delay
+
+```
+set_input_delay (-rise)?
+                (-fall)?
+                (-max)?
+                (-min)?
+                (-clock <clock>)?
+                (-clock_fall)?
+                <delay: float>
+                <pin/port list>
+```
+
+### set_output_delay
+
+```
+set_output_delay (-rise)?
+                 (-fall)?
+                 (-max)?
+                 (-min)?
+                 (-clock <clock>)?
+                 (-clock_fall)?
+                 <delay: float>
+                 <pin/port list>
+```
+
+### set_clock_uncertainty
+
+```
+set_clock_uncertainty (-from <clock>)?
+                      (-to <clock>)?
+                      (-rise)?
+                      (-fall)?
+                      (-setup)?
+                      (-hold)?
+                      <uncertainty: float>
+                      <clocks, ports, pins>
+```
+
+### set_clock_latency
+
+```
+set_clock_latency (-source)?
+                  (-rise)?
+                  (-fall)?
+                  (-min)?
+                  (-max)?
+                  <latency: float>
+                  <clocks, ports, pins>
+```
+
+Note: VTR has `-early` and `-late` flags. Should decide if we want to support.
+
+### set_disable_timing
+
+```
+set_disable_timing (-from <from_port>)?
+                   (-to <to_port>)?
+                   <cell, instance, port, pin>
+```
+
+# Query
+
+get_ports
+
+get_clocks
+
+get_pins
+
+get_cells
+
+get_nets
+
+all_inputs
+
+all_outputs
+
+all_clocks